North East Wind Subsiding over the Crest Today….Might be a bit of haze Thursday….Friday into the Weekend looks a bit unhealthy Air Quality Wise….MJO Presenting some interesting possibilities….

As highlighted….Our NE winds are subsiding as high pressure from the west spreads into CA. At the sametime, the upper low over the Desert SW is moving east.  So the NE gredient weakens and terrain driven wind systems can allow the smoke and or haze to move back into the south county, as early as Thursday, but a better chance Friday and Saturday.  It is diffacult to say how much haze or smoke will return to Mammoth as lot will depend upon fire behavor. At the moment, the was still quite a bit of smoke moving WSW over the San Joaquin valley this morning.

Over all the forecast shows warming today with highs in the low to mid 60s at resort levels and 20s and 30s at night through the weekend. The weather pattern is dry through the 5th of November.

Although both the 6 to 10 and 8 to 14 day outlooks are dry for Mono County, there are some interesting developments in the MJO that “may have an affect on our dry weather pattern.  The MJO is an air sea coupled system that creates upper divergence and upper convergence as it travels eastward, Just north of the equator. The MJO can modulate the westerlies if strong enough. In November and through the Borial Spring, the MJO can contribute to some very benifical storminess for CA if in the right areas geographically. During the LA Nina base state, colder than normal SSTAs exist between 160E east to Central America. This base state of colder than normal sea surface temps inhibits convection. (lack of thunderstorms) This La Nina is regarded as moderate and possibly strong by the time we get to December.

The La Nina Base state can distructivly interfear with the MJO and can rapidly weaken it. This is important because of the signifacant precipitation events that the MJO usually contributes to each winter in California. A winter without a few MJO induced patterns can end up drier than normal to some extent.   That is why La Nina has a bias I think, for being drier than normal.  Since 1950, Moderate to Strong La Ninas accounted for 7 out of 11 years with normal to below normal precip for our region.  And the stronger the La Nina beyond moderate, the greater the odds of dryness in some studies.

Getting back to the MJO, the Phase Space, RMM 1 and 2 is showing a progression of an envelope of convection, from phase space 5 to 8, over the next two weeks. There is some some suggestion of a Phase Space 1 which is back over the Indian ocean, according to the GFS model. The ECMWF has a spurious signeture. IE there is something wrong with it. I need both to get confirmation; Otherwise,  I think we will have a pattern change from out of the west by mid month, (Nov) or a little sooner. This means that an envelope of tropical convection will move through the LA Nina region and eventually re-emerge over the indian ocean……”Possibly”   Why is that imp[ortant? The MJO over the Indian Ocean often teleconnects to a -PNA. (Trof in the mean over the far west or over the extream eastern pacific)

 

Stay Tuned!!

 

Dr Howard amnd the Dweebs………………………:-)

Mono Wind Event Set for the West Side of the Sierra Sunday Night…..Smoke to Begin Clearing Sunday Morning…However, Models are slower with NE flow developing…Now not untill this evening……Colder Weather Ahead…

Sunday 11:40AM

12Z WRF is slower to back the flow out of the NNE today.  The latest guidence pushes it back to between 5:00PM and 8PM Sunday tonight.   Good news is that once the NE flow sets in, It should be around through Wednesday Evening…

 

Looking at a cold night tonight with lows in town between 10 and 15 degrees.  For the most part, the Dweebs do not think it will be much colder, except for the lowest elevations in town, where the coldest air usually is.

 

Outlook is Dry Dry Dry!!!

The Dweeber…

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Saturday 1:00PM

Still Smoky in Mammoth with Hazardous Air Quality.   Air Quality expected to be greatly improved by Mid to Late Morning Sunday.

La Nina now expected to be Moderate to Strong this winter. Atmosphere over the Tropical Pacific has coupled to the cold phase. A Full Basin La Nina is forecasted to last all Winter.   Cold SSTAs now stretch from the Central American Coast to 160 East.   This will most likely confine The MJO’s strength to the Western Pacific,  as once it moves over the anomalously colder waters of Central Pacific, tropical forcing will tend to weaken rapidly, due to the cold La Nina base state with Destructive Phasing the most likely outcome. This pretty much keeps any significant modulating effect of the MJO of the westerlies, well short of where it needs to be to benefit California. So the MJO will be working against us this winter.  Although there are other teleconnections that can bring California Precip, the biggest events by far are usually MJO related.  As a result, many storms will be fighting a ridge resulting in Split Flow Blues for CA.   More Later…..

 

Dr Howard and the Dweebs…………………….:-)

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Mono Wind Event is a Katabatic, Down-Sloping winds much like a Santana Wind for Southern CA.   It does not have much effect on Mammoth Lakes other than to bring colder temps and in this case, to clean up our dirty air. Expect improving Air Quality late afternoon Saturday and into Saturday night with good air quality by 1200pm Sunday.   High temps that have been in the 60s will cool to the 50s on Sunday and upper 30s by Monday, low temperatures will be in the upper teens Monday AM.  This will be followed by a warm up Mid Week into the 60s again.

 

Long Range: No significant precip expected for the next two weeks…..

 

MONO Wind Event: (West Side)  From the NWS

What are Mono Winds? Mono Winds are a localized wind that blows across the western slopes of the central Sierra Nevada and into the foothills below from the northeast. The name Mono Winds was given to these winds because they blew into the central Sierra Nevada from the direction of Mono Lake. The word “Mono” was derived from a Native American tribe who once resided in the area. Mono Winds are strong winds that blow downhill across the western slopes of the Central Sierra Nevada from the northeast. In an ideal atmospheric pattern, air moving from the northeast and flows up and over the high peaks of the Sierra Nevada. As this air rushes several thousand feet downhill, it increases in speed and also dries out. The rugged topography of the Sierra Nevada also causes the air to be funneled through tight spaces which further increases its speed. This results in winds that can reach speeds of 50 mph or more. Mono Winds form when an area of high pressure sets up over the Great Basin. Air flows in a clockwise direction around high pressure. In some situations, the air is “squeezed” better than others because of the differences in pressure in the atmosphere. The more air is squeezed, the faster it blows.

In a typical Mono Wind event, winds reach speeds of at least 50 mph while stronger events can see winds exceed 100 mph! A common set-up in the atmosphere for a Mono Wind event shows a high pressure system over the Great Basin and the direction in which air flows around it. The strength of Mono Winds is also determined by the jetstream, which is the band of winds several thousand feet above the surface of the earth. When the winds in the jetstream are in the same direction as the winds closer to the surface of the earth they can “mix down” or more easily and be transported towards the ground. This enables the very strong and powerful winds that typically blow well above the surface of the earth towards the ground. Jetstream winds are often in excess of 80 to 100 mph at over 20,000 feet in the atmosphere. In ideal situations, these winds speeds will be felt by you (or anything else) on the ground.

Mono Winds are part of a family of winds that known in technical meteorological terms as katabatic winds. The term katabatic winds originates from the Greek Word katabatikos which means “going downhill”. In the case of Mono Winds, air is blowing down the mountains of the Sierra Nevada. Many people who have heard of Santa Ana winds are familiar with how these winds also blow downhill. However, while Santa Ana winds can reach speeds of 50 mph or greater easily, they differ from Mono Winds in that they are winds that rapidly heat up as air descends downhill. Mono Winds conversely are cold wind. They typically form just after a cold front has passed through the region and temperatures have dropped off significantly. Santa Ana winds, owing to their warm, dry state are part of a family of winds known as foehn winds. Foehn winds are winds that are forced down a hill and warm as they do so.

In California, the Santa Ana is the most well-known type, and is the name given to a foehn wind in Southern California. However, other parts of California can experience foehn winds. In the Santa Barbara area, foehn winds are known as sundowner while in the Bay Area, they are known as Diablo winds. Foehn winds are known for bringing a high fire danger with them because of their hot, dry nature. In the case of Mono Winds, the cooler state of the air mass helps to allow for “higher” humidity values. However, because of the speed of the winds, they can still help to spread fires. With the exception of a sundowner, Mono Winds as well as Santa Ana winds and Diablo winds typically occur in the cool season months from October through April due to the seasonal variations in weather patterns.

Its the end of the 70s…..And welcome to the big chill? Best throughts would be to clean up Mammoth’s Air this weekend!….Before it gets warmer again!

Were on the home stretch ending the month of October.  The MJO is stuck in phase 5, and for this time of the year, because of where the tropical convection is over the far Western Pacific, the Rossby Wave train is up and over the top of the “far west”. Actually, the fact that the MJO has been struck in phase 5 for pretty much the entire month of October is pretty remarkable. The results have been an extended fire season over California which is ongoing.

This weekends weather shows’ a cool down. But not the rumored temperatures crashes down into the single digits in Mammoth. We may get into the upper teens at best by Monday AM. You see there is more then one global model, and, they do not agree on how much cooling there will be.  So lows in the 15 to 20 degrees for Monday AM is the most likely range.  Not the single digits rumored.  Daytime highs in Monday will be possibly in the upper 30s? Monday.    As a note, when looking at the forecasts for Mammoth Lakes, it is EZ to get confused about the temperature forecasts.  When reading the zone forecast for Mono County, the low temperatures during (Still Air) are for elevations along Highway 395. It is often up to 10 warmer in the TOMLs,  than those forecasts. Here is the temperature forecast for the next 7 days for the Town of Mammoth. The temps reflect the lows for that morning first.  As you can see, the present forecast calls for lows in the 20s for the most part, early next week.

Note, The weekend system is pretty dry coming in. The upper jet is mainly to our east with downward vertical motion. So do not expect a lot of precip,  just light amounts “If any” Sunday/Night  Best feature of this system is to help with the Creek fire and for home owners to order their wood and purchase wood pellets!!  🙂

Thursday Friday Saturday Sunday Monday Tuesday Wednesday

40/67    35/66    35/61    33/50    19/40     22/52     29/59

 

What the Dweebs see in the longer range is a warm up that following week into the first few days of November. Then a few migratory short wave trofs from the west. The upper jet at the moment, is forecasted too far north to do much good for Central CA. Just wind and cooling and clouds and possibly some showers.  We need the MJO to get into the Phase’s 8, 1, 2, and 3 to get into a stormy pattern.  That will be hard to do with the current La Nina base state at this time. Later in the season the trofs will be stronger. Nevertheless they will be fighting the tropical convection displaced westward and the destructive cool base state of La Nina.  There are other teleconnections that can help…more later….

 

The Dweeber…….:-)