1st Chilly Below Freezing Temps this morning in the High Country…..the next Trof is Colder…but not likely to bring Snowfall that is measurable this weekend….Another Chilly trof will swing through next Wednesday…..Say goodby to Summer this Saturday……

Mammoth Lakes had it first low 30s temp readings this morning since June. The next Trof will bring additional cooling…possibly down into the upper 20s by Sunday AM.  There is another slightly deeper Trof expected to flush through next Wednesday…..A full week away.

Precipitation:

Both ECMWF and the GFS have reached a compromise in the depth of the weekend Trof.  500mb Heights will now remain near 570DM as the bottom briefly swings through. The EC has it coming through earlier Saturday morning while the GFS has it coming through after 00Z Sunday. (Saturday evening)

The main upshot is that no measurable precipitation is now expected Saturday in Mammoth Lakes. Although one can not rule out a few showers and snow showers in the high country.  Nevertheless…it will be chilly and breezy for the Oktoberfest Friday night, and especially Saturday with highs in the 50s.  It will feel like Fall even though Fall does not arrive officially until the next day Sunday the 22nd.

Outlook:

With the pattern remaining progressive over the far west and out over the eastern pacific. The eastern pacific high remaining amped over the central pacific,  supported by the MJO in Phase space 5.  Expect additional trofs to  effect the Eastern Sierra next week resulting in periods of wind, below normal temps and the possibility of light precipitation mid week.

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

Typhoon Man Yi Constructively Phases with Westerlies…..Amplifacation Down Stream this week Increases the odds of stronger Fall Trof Effecting Central and Northern California Next Weekend

Monday afternoon update:

 

ECMWF is stronger with upper Trof for Friday night and Saturday….GFS is beginning to trend deeper…….light Snow in Mammoth Lakes????

After today….say good-by to the Summer 70′s as a series of Gulf of AK trofs migrate through the west coast bringing shots of cooling along with gusty winds.  Although currently active…..the AZ Monsoon will wind down this week as well. High temperatures will cool to the 60s Tuesday with 30s beginning for many areas by mid week….even some 20s possible diurnally for wind protected areas below the inversion.

Now for the fun stuff!

The Autumnal equinox arrives as 1:44pm next Sunday the 22nd. The 1st trof, strong enough to bring precipitation to the Mammoth Area, around the Equinox, the Dweebs consider’s the Equinox storm. This is folklore of course like the Farmers Almanac not Meteorology…….But in Climatology there may be some supporting stats on that. As Jan Null, retired Lead forecaster for WSFO SFO says….Climate if what you expect…weather is what you get.

With a wave train of short waves already taking aim on the west coast…it’s time to look upstream to the western pacific to see if there is anything that might cause extra amplification that may support any global model differences. Low and behold we have a Typhoon Man YI that has recently recurved to the NNW and is now over Japan. Is this what the ecmwf has latched on to….To increase the amplitude over the American GFS Model. A few more days will tell in comparing the two global models. I think that the EC is right because it is better at long-range modeling.

The ECMWF paints between .25 and .50 of precip in our local Mts Saturday and Saturday Night.  Light Snowfall is a possibility as well.

The Next few days will tell if the GFS comes into agreement and the EC stays consistent. Additionally, the Western Pacific is becoming more active and so I would expect several more systems with strong upper jets through months end. Now with this said, western pacific energy may not always phase beneficially for precipitation for the central west coast, so it is on a case by case basis.

The information above may be useful if you are planning a trip to the back country this week as the current forecast is a mostly fair one at this time with just a slight chance of showers Saturday and night.  It looks to be windy at any event for Friday night and much cooler with highs in the upper 50s Saturday in Mammoth Lakes. The Dweebs believe that there will be snow in the back country and possibly Mammoth as well!  So plan on stuffing some thermals in your lederhosen….Friday night and Saturday for Oktoberfest.

More Later…………………………

 

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

Upper low over Nevada to back wash some showers and thunder to the Eastern Sierra….it will be warm and dry this weekend…..1st in series of Fall Trofs to make there way to the Pacific NW by mid week…..Cooler possibly windy weather 2nd half of next week for Mammoth Lakes……

Saturday PM:

 

LI index is -.5 now with .7 PWAT

Convergence along sierra crest is evident with Cu popping.

Some chance of some showers is in order today.

 

Fair and Breezy Sunday

 

Saturday AM update:

Only change this morning is a little extra residual moisture around and plenty of sunshine.  Looking at the SPC, there are no areas of Divergence/Convergence couplets regionally. Just a little extra sun and moisture today as PWATs are up from yesterdays convection. LI are in the plus range. It is going to take a lot of heating to pop a few showers.

Forecast is for isolated TSRW’s but that looks pretty scanty.  Tomorrow will bring clear skies but breezy weather by afternoon. The forecast GFS Proggs are consistent in developing a long wave trof SE of the Gulf of AK and deepening the anomaly to -275DM west of Prince Rupert in the day+ 8 means.  The EC is not as deep.  The GFS also has good upstream amplification north of Hawaii. If the EC jumps on the GFS wagon…..get ready for lots of hype from the media!

As previously mentioned…this is worth keeping an eye on as around the 21st of September is the notorious “equinox storm”. A climo curiosity that seems, but not always….in the cards annually.  One thing is given, it will be much cooler by next weekend………..Prost!

 

Dr Howard and the Dweebs……………………….:-)

 

Thursday AM Update:

No Surprises this morning…. two more days under the influence of the upper Nevada low for a slight chance of TSRWs then a fair weekend. Deep southerly moisture flow out of Mexico affecting the desert SW will shift east as large scale changes initiates stronger trofing in the Pacific NW. So the death blow to summer monsoon is coming soon…..

Long range GFS and GFSX has long wave trofing growing stronger in the pacific NW with eventual amplification upstream. Will keep an eye out for any TS activity in the western pacific as that can either Amp the down stream pattern or weaken it due to constructive or destructive phasing….

Equinox trof now in sight as we move from Summer to the fall……..first dusting may occur during the first week of Fall……..get ready to rake some pine needles that following weekend.

Todays snapshot of the CFS “Climate Forecast System” has normal start to wet season with no early winter.

See: http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/htmls/usPrece3Mon.html

 

Wednesday 5:30 PM

Upper low continues to rotate over SE NV.  “SPC”, shows good divergence over Western Nevada, and an 850-250mb couplet along the Ca/NV border near Bishop Ca later this afternoon.  PWATs are as high as 1.3 over SE Inyo while the moisture gradient thins pretty quickly to .7 over Mammoth Lakes.  Radar has echos over Northern Clark County into Nye County and across the border into SE Inyo County. A few hours ago, there were heavy rains between Desert Rock Nv and Vegas.

Over all it is interesting to note that spokes of divergence at 300mb were rotating around the center of the low…many coupled with areas of lower level convergence. Lifteds were -1 to -3 between western Nevada and southern Inyo county.

The Dweeber……………………..:-)

 

Wednesday AM:

Upper low over Nevada now with counter-clockwise flow at 700mb back washing some moisture into the Eastern Sierra over the next few days. Yesterday there looked to be a storm over the Yosemite valley. For those that want an update on the Rim fire, here is a link to a good blog that will help:  http://northcasmoke.blogspot.com/

High temps the next few days may be a bit cooler, just because of the added moisture and cloud cover with highs closer to 70 in Mammoth Lakes. Lows in the 40s.

The outlook finally shows the upper low moving east by Friday night so that the weekend is clear and dry of moisture. High temps will rise again into the weekend back into the mid 70s with lows in the 40s.

Longer Range:

There appears to be major changes to the larger scale features over both the eastern pacific and far west that will put an end to…the persistent hose of monsoon moisture moving out of Mexico and effecting the desert southwest about the middle of next week. The first series of Fall like Trof’s that have been advertised for over a week now by both the Climate Forecast System and GFX would begin to move into the great basin about Tuesday or Wednesday. This may be a bit fast but it is significant change and about time. The Climo is favorable for a series of Trof’s to begin their march in the Pacific NW about the 3rd to 4th week of September.  The GFS advertises for the Central Sierra,  thickness cooling, gradient, stronger winds and cloudiness, all from the Gulf of Alaska…… and snows for the Cascades!

More Later…………………….

 

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