Archive for November, 2011

Snow Showers possible Thanksgiving Day….Then Fair…Breezy…But Dry Over the Holiday Weekend…….

 

Wednesday morning update:

CRFC QPF update this morning gives Yosemite .01 of an inch of precipitation Thanksgiving Day. So the idea of some snow showers is ok. Mammoth Mt might pick up a trace to an inch or two. That would be the most that I can see. I do not expect much more then a trace or an inch for the town in snow showers Thursday.

Medium Range:

The next system will split further west around 138W. A Cut off low develops well off shore on Sunday….that system will aid in ridging us up over the weekend.

Next Week:

The next short wave to effect the west will approach the pacific northwest on the 1st of Dec. This is beginning to look a bit more interesting from the prospective that this mornings ECMF had this system splitting up over the Pacific NW dropping a cold upper closed low down over Ca. Wednesday night/or early Early Thursday for some light snowfall and much colder temps. The new Wed Nov the 23rd 12z GFS has now come round similar to the ECMWF’s scenario but is about 12+ hours slower, bringing it in more like Thursday the 1st. Back to this mornings EC. Ecmwf moves the split over the far pacific Northwest, brings a southern branch of the polar westerlies down the coast next Wednesday night and then cuts off a deep closed upper low (543dm at 500mb) over SFO at 00z Fri the 2nd….IE Thursday late afternoon. It is then ejected late Friday into the Rockies via the Sierra. The next upstream kicker is shown to have a better over water trajectory coming SE into Ca the following Saturday the 3rd of Dec.

The point is…the EC scenario would produce snow for the sierra both with the 1st system and with the 2nd. The new 12z GFS handels it differently though…..in that it brings a weakening front to the Sierra early Thursday evening then washes it out as an upper low forms over the Central Ca interior (over land). It then drops it SE right down the San Joaquin Valley during the day Friday the 2nd. By Friday night, it is pretty much cut off over Southern Ca Friday night:

This scenario gives Mammoth:

1. Snowfall with the upper low itself.

2. a 2nd chance of up-slope flow and possible some up-slope snowfall Saturday.

In that there is no short term upstream kicker like EC, the cutoff remains over So-Cal until early the following week. The GFS’s kicker is pretty much worthless unlike the ECMWF. The EC’s kicker has better potential for more snowfall in Mammoth the following Saturday the 3rd.

 

So, here are my thoughts:

1. In that we are in a transitory pattern the faith an any scenario a week away is not particularly good.

2. However, with that said, there are two global models that are suggesting more snowfall the 2nd half of next week!!! Say tuned! and Think Snow!!

Next update Monday the 28th.

Have a Happy Thanksgiving Holiday to All!

Dr Howard and the Dweebs……………………..:-)

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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.

Weakening system to bring some snowshowers to the high country Thinksgiving……Global Pattern going through Major Transition…..+Phase PNA pattern the likely result……

OK….this is where we are at….

Over the next few days the split flow pattern over the Eastern Pacific continues with the likely result,  Mammoth getting skunked as far as more snowfall this week. To be sure, I will update one more time tomorrow. This is not to say that we will not get some snow-showers….However a replay of last Sunday is not likely.  The reason why I say this is that non of the models including the global ones bring the splitting system close enough to the coast to bring a front into the Sierra. However, there could be some showers as the storm shears some moisture east.  At the moment, the Dweebs feel that nothing measurable is likely…..but I’ll look again tomorrow AM.

Beyond Thursday….we ridge up…..

The Key Teleconnections for the GFS ENSEMBLES show the Positive Phase of the PNA. IE Far Eastern Pac Ridge/Eastern Trof.

However, The AO is positive so lower pressure is expected to continue over the far northern Latts

The NAO will be neutral to positive as well….not good for any extended term east coast long wave trof.

The Dweebs sense is that we will be going through a dry transitional period over the far west into early December or even, some what beyond. Some of the models bring some energy through the ridge and some down its back side as an inside slider over the next week or two. We can always get snow showers from such systems but those will not get us where we want to be. 

 

The Good News….

The SSTA foundation is solid.

Lots of cold water over the far Eastern Pacific. All the warming that occurred in the late Summer and early Fall is gone. There is a nice warm water pool centered about 170W. It extends east to north of Hawaii, and west to Japan. So the PDO is strongly Negative….good for west coast storms. The QBO has transitioned to its weakly negative stage. Winds above the trop/equator now east to west is some areas…….suggesting a weaker Hudson Bay low if the QBO continues to strengthen in the negative phase.

Most of All, there is “little sign of Blocking in the Greenland Area!!”. Persistent Blocking Near Greenland, Intensifies the Hudson Bay Low which can support a persistent West Coast long wave ridge. If the east stays mild…..it is only a matter of time before winter returns to the high country!

I think that Blocking will be the key over the next Few Weeks or should I say the absence of blocking over/near Greenland. 

 

MJO Update later today…….

 

The Dweeber………….:-)

 


 

————————————————-
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.

Beautiful Clear Day in the High Country with 12 inches of new at the Main Lodge with additional over the Crest……Next Splitting System Turkey Day!

Quick Update:

 

Not much new this morning except the snow that fell over the weekend. Expect a couple of nice days ahead with a slow warm up…then the next splitting system moves SE Wednesday afternoon into Thanksgiving. There is no confidence in any new snowfall forecast until we get closer in time to Thursday. 

Some Highlights though….. The last month of October showed more precipitation then the precious year (2010). However we will be far behind for the month of November if we do not get a lot more snow for this month.

1. Big late season Hurricane now moving west off the coast of Mexico!

2. Very cold Temps over the state of Alaska. (-40 in Fairbanks) This cold is headed for the Northern Gulf of Alaska by Thursday…

Will have an Mjo Update Tomorrow…….

 

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.