Archive for October, 2012

Snow Showery Conditions This Morning and Breezy Weather Developing as upper Jet backs from the Northwest……Slow Warming trend into the weekend now….The weather next week should hold though Tuesday…..

Thursday Update:

Some over running this morning from the NW….  A brief look at 700mb RH for 12zNAM shows an area of 70%Rh over Mammoth this AM, so with the cold air in place would not be surprised to see a few flakes around. With the ridge building in stronger this evening 700RH should diminish and we’ll experience some pretty cold temps over night. The weekend will will warm up. (See discussion below)

Next upstream system begins to move into the area All Hallows Eve and the EC is back with the chance of Rain and Snow. I think that the EC is doing a better job now in the outlook. So plan for the little Trick or Treaters to be extra warm as we may get light snow…..

 

Dr Howard and the Dweebs……………………:-)

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As forecasted…there were snow showers this morning with breezes on the increase.  Based upon the latest vapor wave loop…the bottom of the upper trof has shifted into Nevada while the upper jet has backed to the Northwest. Little moisture is available this far south and so some light snow showers or flurries will continue for a time this morning…mainly over the crest and slightly east. Temps today will moderate into the mid to upper 30s in town while nighttime lows drift down into the teens Thursday AM.

Mammoth MT picked up 17 inches of snow storm total, according to Alex Clayton who manages snowfall amounts for the Mammoth Mt ski patrol. According to Cliff Man of Mammoth Mountain, the snow guns will begin shortly to add to the snow pack as Mammoth Mountain makes plans with their 2012/2013 season opening Thursday, November 8th!

The forecast models over the next several 5 to 7 days indicate that the present trof will continue to progress east while the off shore upper ridge slowly builds into California by Sunday. So expect a slow warming trend through Sunday. Initially, it will be chilly and breezy the next few days with fair conditions over the weekend and very light breezes. Temps may reach the upper 50s in town by Sunday with the ridge axis over us. Night time lows will be mostly in the teens and 20s through Friday then soar over the weekend over the higher terrain as strong subsidence and inversion conditions develop. The 0C isotherm at 700mb takes a hike well north of the area Saturday and Sunday with +6C at 10,000 feet Sunday at 12z.  That will allow nighttime lows at 8,000 feet back into the 30s Saturday and Sunday. Lower elevations will be cold in the teens and 20s.

Outlook:

The upper ridge progresses east while the upper flow coming in from the pacific flattens early next week. The next upstream system Tuesday will bring precip to Northern California and eventually the Northern Sierra by All Hallows Eve. The latest ECMWF 00z Wednesday run has backed off the idea of some light snowfall for the Mammoth area around the 31st/1st for the time being….keeping the storm to our north. So well play a wait and see if that changes…….

MJO:

The Madden Julian OCC is in phase 2 now which for this time of the year highlights a bit warmer then normal temps. However with the present snow cover, that is probably a bit unlikely for our area. There is also a slight bias to the positive side for precip. However, at this time of the year the signal is very weak.

Notes on the QBO:

Here is some interesting notes about the QBO and how it relates to its phase, strength, what it means and where it may go.

The QBO quasi-biennial oscillation (QBO) is a high level stratospheric wind at the very top of the atmosphere  ( 30 mb)   that exists over the  Equator that oscillates from East (negative  QBO) to  West ( Positive  QBO). A full cycle can take anywhere from 18 to 30 months.The strongest positive values are usually around +15.00 or so while the strongest negative values will exceed -25.00 or so. The QBO winds work there way down into the Lower levels and affect weather patterns. Strongly POSITIVE QBO values correlate to Non Blocking  weather patterns in the Jet stream. Strongly Negative QBO values in the cold season Months =  +AO and +NAO patterns

However, QBO values that are “weak” (-10 to +10)
Strongly favor Blocking Patterns over the Northern Hemisphere in the cold season months of November through March.

The Dweeber……………………..:-)

 

 

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Orographics on Steroids was why Mammoth Mt Picked up so much snow….More then twice as much as expected…..Unsetteled weather to continue through Wednesday with Snow Showers today and again Wednesday…..

Many Forecasters forget early in the season, especially after a long warm Summer,  a drier then normal winter, that Mammoth Mt and its immediate area have a very special relationship when 700MB winds blow from the WSW. This storm was a classic case in point of how special local topography (land features), and Orographics (Mountain Effects upon moist winds) can play in forecasting snowfall and QPF. The wettest model, the ECMWF last Sunday, forecasted an inch of precip,(water EQ) just to the west of Mammoth Mt and Mammoth Pass over a 72 to 96 hr period ending Thursday AM. HPC forecasted about .5 to .75 of an inch and several forecasters indicated that was considered wet for the storm who’s upper jet favored the Northern Sierra.

What was actually recorded was close to 2.00 inches up on Mammoth Pass (1.72 according to CRFC), (subject to verification), and at 9000′ (unverified by manual means) 1.8 inches at the Main Lodge.  (18 inches of snowfall); .87 inches W/10 inches of snow on Hillside Dr. near the village. Areas east of Highway 395 had little precipitation to speak of.

Mammoth Pass did not get anywhere near the amounts that some west side, Northern Sierra remote stations recorded. It received about double the amount compared to areas like Yosemite Valley (.89).  Bridgeport on the other hand received .15 of H20, indicating how shadowed areas to the east were.

Currently:

Winds were still westerly this morning at 700mb (10,000ft) and RH at the same level was about 60% to 70% but will decrease to 50% by this afternoon….so snow showers will continue over the higher terrain this morning but will diminish this afternoon.  The next and last wave comes in early Wednesday morning. The flow at 700mb begins westerly but quickly shifts more northwesterly during the mid to late morning as the long wave Trof shifts into the Great Basin at the same time. Thus we loose our orographics pretty quickly after Sunrise Wednesday. The best chance of snowfall with this system will be around Sunrise, as later in the morning the upper flow becomes more northwesterly.

The weekend outlook is for partly cloudy but fair weather under a northwest flow. In that the upper high (500mb), remains well to our west, and apparently does not come in anytime soon, it will remain breezy over the upper elevations with highs in Mammoth in the 50s…lows in the 20s.

Next Trof about All Hallows Eve

Although it is about 10 days away…The Euro is saying that it will bring about 6 to 7 inches over the crest by November 1st.  Lets see how well it does from a distance! 🙂

 

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

 

————————————————-
Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Looks like the Euro Model will be the Winner as far as Snowfall here in Southern Mono County……as of 9:00AM Monday, 8 Inches has fallen at the “Main Lodge” and more coming down!!

10:00PM Update:

“Orographics on Steroids”

10.5 inches at Mammoth Weather.com (8200)

18 inches of new at the main lodge with approx 1.88 of H20 according to the Plot. (not adjusted)

The crest working on possibly 2 feet by Morning…….

Mammoth Pass reporting approx 1.62 inches of H20 eq.

It is still snowing with light to at times moderate snow showers.

Lets face it……All forecasters blew this one.

But who cares! 🙂

 

4:00pm update:

Mammoth Pass received .92 inches as of 3:00pm.  It is quite possibe that Mammoth Mtn got about a foot today.

There still may be a few inches more to come over the next few days. However, the majority is on the gound from this storm.

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The placement of the upper jet was critical for the snowfall forecast here in Mono County. As was the case, the upper jet axis according to the 300mb analysis on the NAM this morning, was right over Southern Mono County at 12Z Monday. That was a good 100-150 miles south of the 24 hour earlier forecast. That’s not good for a snowfall forecast!

Additionally, the system moved in quicker as the heavier precip moved in early Monday AM. It looks like the ECMWF will be the winner with its wetter scenario in forecasting an inch of QPF over the next few days. The Dweebs may even have to update it a bit higher!

What is exciting is that the Dweebs have for the first time, subscribed to the EC and have good access to all the significant parameters effecting our local weather! This should make it easier to dial in a snowfall forecast for the Mammoth area after spending sometime with the model.

As of 9:00AM Monday, it is estimated that close to 9 inches has fallen at the main lodge with between 4 and 5 inches here near the Village at Mammoth. It will be a few more hours before the front moves through so a few more inches is certainly possible! I see no reason why we will not see 5 to 6 inches here at the Village at Mammoth now by this afternoon.

Over the next few days a few more impulses will be coming through. One Tuesday evening and another Wednesday at 15Z (8:00am)

So it is time to do a little homework and see how much more this pattern has in store for us.  Will update this evening after taking a look at the new 12Z ECMWF out this afternoon.

Dr Howard and the Dweebs……………………:-)

 

————————————————-
Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.