Slightly cooler weather ahead with stronger Zephyr expected into early next week…Another dry 7 days ahead….Monsoonal flow becomes more likely between the 21st and 27th of July.

Wednesday Evening the 17th.

The global models are making the change to a warmer pattern next week in Mammoth with a strengthening Continental Upper High, retrograding further west. Expect an increase of precipitable water early next week.  The Owens Valley will become more humid with a chance of thunderstorms beginning Tuesday.

The flow becomes southerly in both the EC and GFS early next week which is not the most favorable pattern for thunderstorms in Mammoth. Nevertheless, isolated showers and thunderstorm will develop as early as Sunday, especially areas along the Mono County convergence zone. Areal coverage will increase through mid week next week. Most favorable upper flow for Mammoth is Southeast flow.  So there will be an increase in convection, but mostly areas east, north and southeast of Mammoth Lakes.

So we will have a chance of Showers and Thunderstorms by mid Week. Should the models become more favorable with SE flow, later next week, the odds will increase for better wetting rains here.


Dr Howard and the Dweebs……………………:-)



On Friday the Town of Mammoth experienced its warmest day of the year with a high of 77 degrees. Early morning lows were in the mid 50s Saturday AM.  Late afternoon isolated thunderstorms occurred over the more favorable Bodie Hills north west of Mono lake Friday afternoon. This is a common area for convergence type heat related thunderstorms that happens in July when the flow is light enough out of the west southwest, meeting the afternoon diurnal southerly flow coming up the Owens Valley and Eastern CA.

Convergence type thunderstorms and daily air-mass modification can produce some locally heavy rain in those areas, if dryer air from a stronger southwest flow does not develop soon enough. This year, plenty of episodes of SW flow seem to be the norm.  In fact stronger Southwest flow is Developing this weekend, so today Saturday should be the last day for isolated thunderstorms for this episode. One more note…these thunderstorms are not related to any monsoon pattern which is defined by the seasonal wind. (Synoptic scale SSE upper flow). The earliest opportunity for that pattern to develop will be week two according the the global models…..Or beginning about the 21st……

Expect the weather in Mammoth to remain dry for the next 5 to 7 days…..High temperatures will cool to the low to mid 70s by Sunday and Monday…….lows in the 40s. The Zephyr will strengthen with gusts to 35mph Sunday PM. Thereafter, a warming trend is expected the second half of next week…..

According to ECMWF and GFS models….Longer Range week 2 becomes more favorable for some southerly flow with possibly Southeasterly flow aloft at 500mb. Although the Monsoon has not developed over the west or even the desert SW to a significant degree….climatically, the last week of July is the most favorable time frame, so we are getting closer time-wise in Climo.


i will update on the progress of any Southerly flow or Southeasterly flow the middle of next week for the following week.


Dr howard and the Dweebs…………



Cooler Breezy Weather the next few days followed by a warm up mid week…..A few isolated thunderstorms are possible Wednesday thru Friday…..High temperatures still running below seasonal norms….

Wow! Temps really warmed up today….74 in town.   That may not seem like much, however, the spread was only 6 degrees from the Mammoth AP vs 10 yesterday.   We have lost a lot of the cool air associated with the trof as it is gone.   Expect highs to climb now into the upper 70s this week. The warmest of the Summer so far.  Isolated thunderstorms of the summer time verity are possible beginning tomorrow over the Mono County convergence zone, mainly east of Highway 395. The next trof will bring cooling by the Saturday or Sunday with gusty west winds, especially Sunday!  Critical Fire Weather possible…


Longer Range:


Still Waiting for the Monsoon….

Looking at both the GFS and ECMWF, the is the chance for some southerly flow developing next week.  It mainly affects the Southern Sierra, but it may get up here for a few days for some TSRW action.


More Later….


After a beautiful Holiday and Weekend, toughing at 500MB has extended southward again bringing high clouds and causing about 6 degree of cooling to Mammoth Lakes on Sunday.  I expect this Trof to linger into Monday with it lifting out to the ENE Tuesday AM.  There after, we warm up again into the low to possibility mid 70s.  74 is the normal high for this time of the year so we have a way to go to get there. So far, we are experiencing a much cooler than normal Summer.

Looking at the PWATs over the next week and two….Our air-mass stays pretty dry for the foreseeable future. However there will be periods of weak convergence like on Wednesday and again Friday over Mono County. This means that there could be a few isolated heat and convergence related  thunderstorms, mainly east of Highway 395.


Longer Range:


Long Range 500MB charts from ECMWF has a Easterly displaced Continental High in the mean. This means that the upper flow will have more of a dry SW bias this Summer. It could be one of the driest and breeziest Summers in decades for Mammoth Lakes.

Note; if this pattern should continue into the fall, that would increase the odds for early season snowfall…..


Dr Howard and the Dweebs……………………:-)

Forecast models now delay the demise of the West Coast Trof until the 9th….Transition to much warmer pattern now about mid week next week….

Our persistent west coast trough looks likely to hang on now through the end of this week. This will delay the normal lapse rates between Mammoth and Mammoth AP until early next week. Expect our afternoon and evening zephyr stronger than desired. High temps have been running mid to upper 60s at 8K with afternoon winds in the 15 to 25 mph range out in the meadow. As a comparison. Mammoth AP has been running mid to upper 70s for highs. As soon as the anomalous cool air over the upper elevations associated with this trof moves out, sensibly, there is going to be a huge warm up!  That will begin to take place by the middle of next week.


Expect daytime highs 65 to 70 at 8000 feet through July 4th. Nights in the upper 30s to mid 40s. It will be very dry.  The weekend looks a little warmer with the possibility of some very low 70s. Although the trough off shore is weaker, there will still be an enhanced zephyr. However, not as strong as what we have now.


Temperatures over Long Valley have been running in the mid to upper 70s this week. For July 4th, expect high temps to continue in this range. Early morning lows have been in the  30s and 40s. Don’t forget to bring a  jacket if staying for the fireworks show Thursday night. The temperature at showtime will be near 59 degrees. Winds will decouple by 9:00 pm so they should be lighter for showtime.

Expect a slightly warmer weekend…..



Looking at the Euro and CPC outlook for this summer for our area for Precipitation and Temps, it is apparent that we will experience a Summer of much fewer thunderstorm days with daytime temperatures that will be more normal to below normal at 8000 feet. This means that it will be much less likely to experience our average highest temperature of 88 degrees this summer.

There is likely to be more weak west coast toughing and thus additional cool air in the higher elevation like now, leading to a much breezier summer. Expect an enhanced Zephyr, as compared to the summers of past 5 years. This zephyr will push the Mono County convergence zone well east of its usual position in the mean, and lead to a drier than normal Summer for the high country. As a note, we are not likely to be thunderstorm free, However, the number of thunderstorm days will be much less than normal, west of highway 395. It also appears that the AZ monsoon season will get a later start. As a note, the Southern Sierra will experience closer to a normal thunderstorm summer with more thunderstorm days than both the central and northern sierra.


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