Say Good-Bye to Spring today…the first day of Summer arrives Saturday with the Summer Solstice arriving at 3:51AM Local Time….High temps in Mammoth will waist no time at all getting into the low 80s by Monday-Tuesday next week….

As we say good by to Spring….The next transition will be from the current Spring like pattern of weak migratory trofs moving into the pacific NW, modulating our local Zephyr, to a pattern highlighted by a strengthening continental high over the four corner states.

It is always fun to watch this transition from a global model point of view, as Climatology points the way, with the models usually following. Currently, the models are showing the first real development of a toasty pattern that brings the warmest weather to the Sierra of the year. The models are timing it to build about July 2nd through the 4th of July Holiday Weekend, as the ECMWF has the toasty 594DM Height isohyet into the Eastern Sierra for the 4th of July holiday itself. I would suspect that the heat will continue well into that following week, unless we get an early season TSRW outbreak.

It is at this time within the first 10 days of July that the highest temps over the Eastern Sierra usually occur.  Why? Not only is the Sun the highest in the sky, The strongest surface heating/convergence and diffluent thicknesses process is occurring to the SE over the Desert Southwest. A strengthening continental upper high is occurring, while SE flow usually does not really established itself in early July. Thus our air mass is initially stable. With a favorable pattern, temperatures can reach into the upper 80s and sometimes low 90s in Mammoth depending on where the core of the upper high sets up. Thereafter, The Desert Monsoon Season kicks in. Easterly waves forming in the underbelly of the continental high, pushing westward or northwestward, occasional moisture advection and most importantly favorable surface convergence over our elevated heat source can trigger thunderstorms.  So while the Cap of an upper high allows heat to build within the air mass, once that cap weakens or shifts east, the lid comes off allowing an outbreak of thunderstorms. Thus the 2nd week of July is most favorable for a heat wave related thunderstorm outbreak pattern over the Eastern Sierra. This is the Climatology of that time here in Mammoth. With that said, that is climatology and what we expect, weather as we well know is what we get. So Thunderstorms may erupt over the July 4th holiday, providing a little of mother natures own fireworks as well.


In the meantime, say good by to Spring today…..1st day of summer arrives Saturday at 3:51AM…..  Highs in Mammoth now in the mid 70s jumping to the low 80s by Monday or Tuesday. There is expected to be one more brief pull back in temps going into the following weekend of the 26-28th….Then Mother Nature cranks up the heat…for the July 4th Holiday weekend and beyond…..


Dr Howard and the Dweebs…………………..:-)


MJO over Phase Four to begin weakening or progressing Toward Phase 5….Robust Trof to shift East out of Area Tomarrow to Insure a warm weekend……Winds To begin to diminish Wednesday………July Fourth Holiday to be a Toasty One from an Interseasonal Perspective…..

Wednesday AM:

This mornings freeze qualified climatically as the last freeze of the season. The timing of that was right on with Fathers Day usually the last freeze. So the Climatology was great!. The Dweebs do not expect any more freezes in Mammoth Lakes at the 8000 foot level until fall now. However, that does not mean that we are done with warming and cooling periods as well as windy periods. There is another moderate trof on the horizon for the last weekend of June that will have wind in store for the high country along with cooler temps…then a warm up through the 4th of July. July 4th should be a bit breezy but well into the 70s…..

At the moment, we are now in a rapid warning trend that will get us into the upper 60s today, then low 70s by Thursday. Mid 70s Friday and Saturday then close to 80 by Sunday into early next week.

A cool down with wind is expected the following Friday into that weekend.


Yes its been windy….And cooler than Normal…but the Dweebs did warn you of all that.   The good news, is that a break in the wind and cool weather is coming up by Thursday. That break should continue through the weekend. When the MJO is in phase 4 this time of the year, the odds are good of pattern of wind and cool for the high country of the Sierra. The progression or weakening of that wave in that area of tropical forcing over the Western Pacific will allow the west coast trof to weaken. So warming with less wind is in our forecast for our region  or the weekend.

Over the long-term, the dynamic MJO model strengthens somewhat the MJO again near this region or a little further east. Thus another trof…..however weaker will move toward the west coast next week bringing another spell of wind and cooling. However, the cooling and wind is not likely to be as strong as the current one.  As we move toward the end of the month some real signs of Summer begin to take hold. At the moment, the Dweebs are expecting a very warm end of the month of June…..well into the 1st week of July. However, with that said, if a real El Nino is shaping up, it may not be long until weather patterns begin to couple with that equatorial warm water near the dateline. That may spell more wind eventually for our summer and not as persistently hot as during the past several summers.



Mammoth….today low 60s…then upper 60s Wednesday.   Lows in the 30s tomorrow AM

Thursday through Sunday will be warm with highs in the low to mid 70s…..while lows will be in the 30s and 40s



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

Monday the Warmest Day…Then Scattered Thunderstorms to Rumble in Response to a small closed low arriving just at the right time Tuesday PM…….The MJO Maybe Ready to Kick Start El Nino Soon!!

Thursday AM:

Wind developed overnight in the higher elevations with the top of Mammoth MT gusting to 55MPH at 7:00AM. This winds will get pulled down into Town later this AM as the daytime heating progresses. However, the winds forecasted for town will not gust much more then 40MPH. The very breezy weather will continue through Friday night.



Note….This is not a forecast…just something to watch for

What kind of weather would we expect to see this summer if a strong El Nino was on the horizon for the next Fall- Winter.

Some signs to watch for:

1. Perpetual weak trofing along the west coast and a displaced continental high South-East to eastward from the four corner states.  A weaker Monsoon Season for the Desert SW.  Not as hot a summer. IE Hot episodes to be either shorter lived or not at all.  A much breezier Summer with much less thunderstorms. The Spring Breezy season continuing into the first week of July with a bit cooler than normal temps.


More later……


The Dweeber




Wednesday PM UPDATE:

An annoying windy period will begin later tonight and last through Friday night. Cooler temps on the way. This nasty trof will be very dry in the high country, increasing fire concerns. Winds up to 45MPH are possible in town at times….

For you locals, the pine pollen is on the increase and so you might want to think about closing your windows to keep the pollen out the next 60 hours….


The Dweeber……………………………………>>>



Tuesday Update:

It looks to be a busy afternoon for Fire Crews as scattered dry thunderstorms are expected develop within the deformation zone associated with a weak upper level low pressure feature coming into Santa Barbara today.  This will create weak divergence aloft over the Sierra. Although our air-mass is currently dry in the midlevel’s, there will be plenty of moist parcels of air that will rise from the surface into an increasingly unstable air mass, by mid afternoon. There is expected to be some residual moisture around Wednesday. However, not much of a lifting mechanism as there will be today.  So expect just isolated air mass TSRWS Wednesday.

By Thursday, a stronger “open trof” moves into the pacific NW with its dry cold front flushing through the sierra during the day. A clash of air masses with gradient driven winds will develop ahead of the front combined with a surface gradient due to the difference’s between the existing ambient heat of our current air mass and the WX front approaching.  Thus it looks windy Thursday here in Mammoth, especially during the afternoon. Fire weather concerns are in the forefront, “if”any new fires are created by todays anticipated lightning strikes.

Post frontal Thursday, it will grow cooler with about 10 degrees of cooling between yesterdays high of 79 and Friday’s 69 degree high.  Night times low will cool to the 30s again over the weekend.

During the first half of next week, all the models bring warming back into Eastern CA. However, there is a big contrast on what happens the 2nd half of next week.  You see the ECMWF Control sets up a classic Summertime pattern with warming over the west followed by a strong continental high setting up over the Great Basin.  Furthermore, the upper height anomaly sets up later over the four corners area in a pattern, suggesting the possibility of an incipient monsoon developing by the end of week 2.

As a comparison, the GFS control over the same week 2 period, has another significant trof effecting our area keeping temperatures seasonal, with periods of wind.  These two models during the latter week two period are about as different as they can be!!


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



After a beautiful weekend…..The Dweebs see some Thunderstorms in our future.  Although the Thunderstorm action has been pretty isolated the past few days, that is getting ready to change as warm ambient temperatures react with a dynamic Vort max coming in Tuesday. This will have the effect of strongly destabilizing the atmosphere Tuesday afternoon and into the evening hours.


The rest of the week will be a bit cooler. The forecast models have been back peddling on the colder scenario for sometime now, for next weekend. It now looks like it will be cooler and breezy Thursday into Friday, but no major Cool down with this system. Temperatures will cool to the low 70s in Mammoth. These are more seasonal temperatures then anything else. However, there looks to be a few others low pressure systems before the end of the month that we will have to keep an eye on as far as cooling and wind.


El Nino>>>> Moderate…Strong or Super!

Here is the process.  Atmospheric Teleconnections>>>>>>MJO>>>>>>Westerly Wind Bursts>>>>>>Kelvin Waves>>>>>>>EL Nino


For the past five to six European weekly forecasts, the model has been becoming more and more aggressive with a developing MJO signature to push across the central-eastern Pacific later in June through early July. In response, we should expect another period of westerly wind bursts over the western-central part of the Basin.  See:

For a more detailed report, check out this timely report from Dr. Michael Ventrice.


The Dweeber………………………………:-)