Scattered Thunderstorms the next few days then drier/warmer over the weekend…………………………



Sunday AM Update:

Our first shot of Monsoon Moisture arrived late yesterday afternoon as evidenced by Altocumulus advecting from the SE over the Sierra.  Dew Points are up into the mid 30s now, and with strong daytime heating, extra lift and higher heights, isolated TSRWs will break out from our first SE flow episode of the Summer. Our local air mass will continue to modify this week with the aerial coverage of thunderstorms increasing and high temperatures falling off by Tuesday from the 80s to the 70s. Both today Sunday and tomorrow Monday may be the warmest days this week, as more and more moisture increases within our air mass, and it clouds up earlier. 

Guidance from earlier this morning showed a vort max over Southern Inyo County moving NW. This will have the effect of enhancing instability this afternoon and rainfall chances. With the orientation of the upper high over the Utah the next few days….more instability will enhance rainfall chances over time. Thunderstorms will grow wetter with the possibility of areas of heavy rains and flash flooding. Although the Dweebs will follow the developing situation closely, stay tuned to the National Weather Service for advisories as that will effect your outdoor activities this coming week.  We could have “some” very active weather days this coming week……


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


Here is your July 5th afternoon update for you Weather Dweebs…………………….

First of all……Near record crowds here in Mammoth this weekend.  I though that I would sneak into Vons to shop during the Crowley Lake fireworks show and it would be slow. Not a chance…the line was backed up into the Produce Dept at 10:30PM.

Kudos To Larry Johnson for another very creative Float during the Parade Friday. It was a page out of Jurassic Park with a seeming live Velociraptor chasing down Old Mammoth Road, I guess looking for something to eat. T-Rex was in front of him and A brontosaurus was ahead as well. The neck of Bronto- looked like is was possibly some 30 to 50 feet in length! Otherwise the weather was perfect!  Upper 70s…..and a nice zephyr breeze in the afternoon.

WX Discussion:

Over the next two weeks were going to remain quite toasty with a strong Subtropical Continental Upper High over the Four Corners states. From time to time, a weak trof will flush the Mammoth Pass with drier air. However, today’s guidance showed monsoon moisture pulsing back and thus winning the weak trofing fight for the Sunday through Tuesday Period.

The weak trof that has kept us dry the past few days is now lifting out and a pulse of Monsoon moisture will move back into the area Sunday with more afternoon clouds and a slight chance of some thunder. An increase in dynamics and surface convergence will occur early next week with the best chance for some rain about Tuesday. Thereafter……Another weak trof is expected to bring more of a zephyr Wednesday and Thursday with less of a thunderstorm threat, before the next surge of moistures moves in Friday into that following weekend.

July Outlook:

Interesting enough is that as of this morning….NCEP’s Climate Forecast System Version 2 (CFSv2) is calling for precipitation to be +200% of normal for the Mammoth Area for the month of July. That means that we should get some meaning thunderstorms and rain this Month. As a comparison, August precip is expected to be near normal.


Here is your updated Temperature and *POP forecast for Mammoth Lakes beginning Tomorrow Sunday:

(POP)= Percentage of measure precipitation of at least .01 of More.

As you can see Tuesday has POPs of 30%


56/80       55/84       57/80       57/78       54/77        54/76       51/75
10/20       20/20       20/30       30/20       20/20        20/20        20/20




Weak troughing along the California Coast will provide for moderate zephyr winds and slightly cooler temps the next few days…Daytime highs will cool to normal (78) today Wednesday and remain through Saturday July 5th. However, the AZ monsoon will develop rapidly in that region as the continental high builds west and the upper trof currently off shore is forced north. the Global Forecast System (GFS) shows a Southeast mid and upper level flow developing.  1st over extreme southeast CA Friday, then reaching into Southern Mono County by Sunday. Thus the gates to dynamics and mid and upper level moisture will begin to increase by Late Saturday or Sunday.

Initially, TSRWs will be isolated Sunday. However, as time goes by, our air mass will become more saturated next week as the convective process builds. This will have the effect of adding moisture within the system from the top down over time. The effects of the monsoon process, IE South East Flow should not be focused so much on Moisture Advection….but rather, an increase of Dynamics as small scale features within the upper SE flow create opportunities for enhanced instability. Sure there is moisture advection, however, moisture advection at 700MB without a lifting mechanism is like gasoline without a spark.

Initially, storms will form and be focused within areas of surface convergence. Meaning they will be high based with small areal coverage. As time goes on, our air mass will juice up from within the localized system/process.  Eventually a combination of moisture advection and possibly deeper moisture will arrive, and if a significant trigger (Easterly Wave or Vort Center) moves up from the South or South East; heavier rains “may” occur next week.

I guess you can say that with the advent of the AZ monsoon…the transition to a full on July Summer Pattern is complete.


Sensible Weather:

Dry through Saturday in Mammoth with afternoon buildups Saturday. Highs in the upper 70s today through Saturday with lows in the upper 40s….rising to the 50s by Sunday and well into the 50s next week.  High temps next week will probably begin in the low 80s then cool due to the convective process into the 70s. Isolated “dry thunderstorms” or storms with narrow rain shafts are expected Sunday with the areal coverage increasing next week with the possibility of wet storms as well.  The climatology is good next week for storms with wetting rains…… both 6 to 10 day and 8 to 14 day precip outlook has somewhat enhanced precipitation possibilities for the sierra through mid July.

Have a Save and Sane Holiday Weekend and Remember…..The discharging of Personal Fireworks in Mono County is illegal and especially dangerous this Summer! We have extreme fire conditions here. Mono County will have a great Fireworks display put on by professionals at Crowley Lake, Friday Night at 9:00PM…..As well as at the Village at Mammoth over the Holiday Weekend.


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