Archive for year 2014

Dry Weather is expected over the Eastern Sierra through Monday with a Warming trend through Sunday……Monsoonal Flow Resumes Tuesday with an increasing chance of Rainfall for Mono County…

After a couple nice days of rainfall the weather will be dry here in the high country with a strong warming trend Through Sunday.  High Temps by Sunday and Monday will be in the upper range of the mid 80s with lows in the low 50s. South-East flow and dynamics will return Tuesday through Thursday next week along with Rain Showers and Thunderstorms.

Enjoy the Wine Fest…..Later today and Saturday…..Two of the best wineries will be attending from the Howell Mt appellation in the Napa area. “Saunter” and “Outpost Winery’s” are some of the best from that region!

 

Discussion:

This mornings guidance along with the water vapor loop shows a weak trof of low pressure off the CA Coast at 135W, ushering in a drier SW flow into California. With the drier air, comes a more stable air mass, more sunshine, rain free conditions and slightly warmer temps. The upper low will not come inland, but instead, lift north along the same longitude in response to increasing heights from the east over the weekend. The result will be that the continental high over our countries mid section will retrograde west over Nevada and California by Sunday.  This westward shift will challenge the warmest temps so far this Summer here in the Eastern Sierra Sunday, and again Monday.

Next week the guidance suggests that the upper high will begin to weaken and a SE flow develops again out of the Desert Southwest. A Rich Moisture source is currently in place over NW Mexico. This in time will be drawn north into AZ then NW into Eastern CA Tuesday through Thursday. This South East flow is the Monsoon, (seasonal wind) which will be accompanied by a more dynamic, unstable air mass….And the possibility of additional rainfall for the Sierra.

If you remember, the Climate Forecast Systems forecast for the eastern sierra for July posted here in the Dweeb Report had indicated that precipitation for July would be in excess of 200% of Normal. Normal is probably about an inch of Rain for the month of July here in Mammoth. Yesterdays Rainfall tallied between .2 and .4 inches over the Town of Mammoth Lakes.

Kelvin Wave:

Another robust kelvin wave is located over the Maritime Continent and is progressing east along the Equator. In the front of this system is a down welling component that showing up, evidenced by the warming of the subsurface ocean waters between 160E and the Dateline.  In my opinion,  this looks like it will effectively re-energize the Nino Basin later this Summer and Fall. You can track this Kelvin Wave at the following link and watch its progress this Summer and Fall.

SEE: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/anim/wkxzteq_anm.gif

ENSO:

The latest advisory from the CPC indicates that there is a 70% chance of a Weak to Moderate by the end of the Summer.  Furthermore, those odds increase to 80% by Fall. The Dweebs believe that a Weak to Moderate El Nino will have an affect on California’s weather pattern next winter and Spring.

The ONI index is used in the following study for determining El Ninos effect upon precipitation over California. This research has been a work in progress by Meteorologist Jan Null a current CCIM and past lead weather service forecaster in the Bay Area.

You can review his work here at this link:  http://ggweather.com/enso2014/

Also since there is likely going to be a lot of rumors flying around the next 6 month about El NINO, I though it would be appropriate to include Jan Nulls List of Myths, some of which you may actually hear from someone this Summer or fall…

SEE:  http://ggweather.com/enso/enso_myths.htm

Have a great weekend

 

The Dweeber………………………:-)

Current Episode of Moist SE flow to begin diminishing by Friday leading to a fair warm weekend……In the meantime, High Country Showers and Thunderstorms possible, shifting a bit east Thursday…Then Dry Friday through Sunday

There has been a nice moist SE flow pattern over the Sierra the past few days…however little in the way of a trigger for heavy rain until today…Today looks to be the best day for some substantial rain over Mono County….With POPs as high as a 60% Chance!

Scattered Thunderstorms will redevelop Wednesday…..However, without as big a trigger as today. Nevertheless, storms may form again and areas of heavy rain possible tomorrow.  A weak trof of low pressure will begin to back the upper flow from the SSW Friday with even more SW flow Friday night into Saturday. The weekend looks fair and warm with highs returning to the low 80s by Sunday.

 

Outlook for next week:

The Subtropical upper high builds back into California by Sunday and remains the dominant feature next week. A combination of light flow aloft and daytime heating will result in the typical air mass thunderstorms with forcing mainly the typical high elevated heat source of the Sierra in addition to the usual surface convergence that is moves about on a diurnal bases. At this point, I do not see another Strong SE flow set up….that is not to say that one could not develop between today’s model runs and the end of the weeks runs for next week.

 

ENSO:

The latest numbers for the Nino 3.4 and 4 region are pretty anemic. The very strong Kelvin wave that moved across the pacific has run its course. This is at least, part of the system that created the very warm SSTA’s, South East from Pt. Conception to San Diego where sea surface temps are as high as 78 degrees off the San Diego Coast and positive SSTAs are also found south along the Baja Coast.

The latest weekly Nino data shows that during the time period of June 25th through July 2nd, all Nino regions of the Nino Basin have cooled with the exception of Nino Region #3. This was a direct result of the rear upwelling phase of the Kelvin Wave.  As of late, a new but weaker Kelvin Wave is beginning to increase the sub surface temps and thus making an effort to renew the heat in the NINO basin over the next few months. The Down Welling phase in its nose is warming the subsurface heat content at longitudes of 160 East to 180 West.

SEE:  http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/anim/wkxzteq_anm.gif

At this Time…it is the opinion of the Dweebs that it is highly unlikely that we will have a “Super Nino”, one which SSTA’s are at, or above +2C in the Nino 3.4 region. However, even a weak El Nino (.05C) can bring a normal amount of Precipitation to Southern CA and a winter that is 80% to 90% of normal to the Central Sierra Crest. There are a lot of Split flow systems in a Weak El Nino and so coastal areas of Central and Northern CA can get a lot of rain while interior sections can get much less.

There is no real way to predict with much certainty what the winter will be like until the Early Fall, as by then, well have a better idea on how the Nino regions are doing heat wise as well as the other teleconnections that will be effecting the weather for the upcoming winter.  One thing is known at this time….The PDO is positive and the QBO is negative which argues for another cold winter east of the Divide.  The big question will be…Will the stronger than normal subtropical upper jet be strong enough to flush out the cold air from the Hudson Bay > east out over the Atlantic next winter…..

 

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

 

 

 

 

 

Dry SW Flow to Continue Thuough July Fourth With Moderate Zephyr Winds…..South-East Flow Develops later in the weekend as the AZ Monsoon Rapidly Shifts into High Gear Next Week……….

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%

 

MAMMOTH LAKES:
PTCLDY   PTCLDY   TSTRMS   PTCLDY   MOCLDY   MOCLDY   PTCLDY
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

 

 

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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………………………………..:-)