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Archive for December, 2011
Colder next week and unsetteled…snow showers a good bet early then again Thursday…..MJO still active and moving east….
Saturday December 10, 2011
I guess it frustrating being a snow farmer here in the high country. Often times we either have too much snow or not enough. When you Ol timers talk about the dry years of 1976 and 1977 remember, that Mammoth MT did not have snow-making back then.
At this time, skiing continues to improve as more and more trails open. Mother nature is cooperating with colder then normal temps over the far west. Mammoth Mt will be able to lay it down even quicker next week. Realize that the bases of snow in most ski resorts in most areas of the country are quite deficit of normal snowfall for this time of the year. Some may not even open! So enjoy the holiday. The skiing will be good and quite possibly the best….in the far west!
I. Weather
A. Next Week
Two systems….the Monday system will dig south down the coast and effect Mainly Southern Ca and then the Mts of Arizona.
The second system may surprise us as the EC is a bit wetter then the GFS. That one will be Thursday and would probably give us several inches before the weekend. 2 to 6 possibly (just a guess at this time as it dives south over the State). Otherwise nothing much to get too excited about at this time through the end of next week.
II. MJO
In Phase Space V. Defying the models as far as its strength and in relation to its location. This might be the game changer for week 2. There could certainly be a transition and during the transition, a storm might sneak in here.
Teleconnections:
Effects? One scenario It may be that it just turns wet in the Pacific NW and eventually brings back the cold to the East. (+PNA) However, with time, it may help begin the blocking process over Greenland and cause the shift from a strong +AO to one that goes negative. That would have good implications for us later in January as the shift back to a -PNA with a -AO would be just what we need.
Comments by the Dweeber on the December 1st Mono Wind Event.
There have been lots of questions the past 10 day about the Mono Wind event that blew down some 500 to 1000 pine trees some of which were 20 to 30+ inches in diameter I am told.
The most simplistic explanation has to include the WX conditions before and during the event.
The antecedent conditions were highlighted by several days of above normal temperatures here in Eastern California with highs as warm as 60 in Mammoth and the 70s recorded in Bishop.
Mammoth WX had high temps of:
Nov:
27th 58.7
28th 55.5
29th 59.6
30th 45.9 (beginning of event)
So the antecedent conditions were anomalously warm
before the event.
On Wednesday Nov the 30th, we had a dry cold front
come through early in the afternoon, the high for that day occurred
about 12:00pm.
On December 1st the high temp peaked at 26 degrees
in snow showers.
During the event, As the developing short wave moved south it became closed in nature at 500mb over or just west of Vegas. The upper flow then veered to the ENE over Mammoth Mt early Thursday Am as the upper jet of 140knots became more ENE orientated during the morning hours. It was estimated that the best Wave Breaking occurred after midnight with the wind shift from NW to NE. The time about 4:00am (12z Dec 1st) the winds were especially strong.
During the peak of the event.
300mb winds were 140knots out of the NE
500mb temps
were aprox -25F
I believe that 1000-500mb Thicknesses bottomed south of 534dm that day.
Winds were
65Knots sustained at 700mb out of the ENE
Tree Damage most likely due to wave breaking on west
side…..*Where strongest winds surfaced on Mammoth Mt’s Back side
from time to time over a 2 to 3 hour period around 3AM to 6AM.
Note: Wave breaking is Akin to the upper jet briefly
surfacing. In this case on the back side of Mammoth Mt.
Over the top of Mammoth Mt, Winds were report by recording equipment at 150mph, pegging limits of
equipment for about 3 hours.
WSFO-RNO forecaster estimated in their AFD, gusts possible between 170 and 180mph over the crest. Some of that could have surfaced in the affected areas although at lower speeds.
Note: In forecasting Mammoth Mt winds on top, the formula is to use the sustained winds at 700mb and double it for the
top. So winds were forecasted by the models to be at 65knots at 700mb, Doubled would be 130knots or 150mph. Often times, Winds tend to be higher over the top of Mammoth Mt when out of the east or Northeast. That may have accounted for the higher speeds.
Other wind events have occurred in areas like
Crowley Lake:
Where a 140 to 160 knot northwest upper jet, slices through North Central Ca. Then combined with precip on west side of the Sierra, resulting in strong down sloping winds with recorded speeds of up to 140mph across residential sections of Crowley Lake out of McGee Canyon. Wave breaking and down sloping no matter how/where
it occurs has had serious effects upon areas of Mono and Madera
County’s over the years.
The Dec 1st event was a classic Mono Wind Event!
However, possibly more like on steroids
The Dweeber……………………………….:-)
*According to Scott at Mammoth Mt.
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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.