Archive for October, 2012

UPPER LEVER LOW TRACKING SE DOWN THE COAST THEN INLAND THURSDAY……

 

Wednesday PM update: Wednesday 2:55pm mst

 

The latest update shows the upper cut off still dropping SE off the south central coast. latest guidance shows that it taps into a fairly rich source of subtropical moisture. The upper center comes inland south of Santa Barbara Thursday morning. With good divergence developing in east to north quad.   Most of the precipitation for the Mammoth area is expected beginning by Thursday afternoon with highest RH expected beginning later afternoon then into the night.

freezing level will lower Thursday to 10K then to 9500 by Friday with the snow level about 1000 to 1500below that level.   Mammoth above 9000 may pick up a few inches of wet snow…..and over the crest as much as 3 to 5 inches.

the dweebs still on vacation but will update now and then………

 

The Dweeber…………..

Blocky patterns especially in Oct are fickle. This one is no different. There have been enough runs the the guidance is in agreement to take the cut off down the coast then inland across Southern Calif Thursday. The Dweebs feel that the majority of the precip will occur as upslope over the Sierra from moisture circulating around the upper low.  700mb RH and 0c isohyet flirts with Mammoth for a few days beginning Late Tuesday. So a few inches of wet snow possible latter Tuesday through early Friday.  The weekend should be fair with warmer temps…..that are seasonal for mid Oct. There after the westerlies take a hike to the north fora while.

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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.

Confidence is high that a cooling trend will continue through Tuesday Next Week…Cut off low under Blocking high in the Gulf of AK will be slow to progress out of Ca next week…..Snow showers over the higher elevations is a possibility Monday Night into Tuesday Night……

Well its time to say good by to the 70s….at least until the 3rd week of October 😉

The developing REX block will take its good old time in releasing its better half!  That’s the upper cut off low currently off the west coast.  Today Thursday will be the last of the 70s at resort levels for at least a week. Highs cooling to the 50s by Sunday and even low 50s by Monday-Wednesday. Nigh time lows headed for the 30s or ?  The 00Z Friday GFS has the track coming in with the center south of Monterrey Bay. Mammoth gets into the Front Left Quad……Divergence Aloft, WU! WU!   The ECMWF is still pretty wet for early next week and the GFS is growing a bit wetter. So..as cut-offs go, and although it is a bit early at this time…..we may see a few inches of snow next week on O’l Woolly. I say that, as the 0C isotherm at 700mb grows as the upper low approaches the coast. (slight deepening) The freezing level will drop to 10,000 feet or so. The upper cut off may slow or stall over Southern Ca for a day allowing some up-slope as well.   The longer range is consistent in damping the pattern across the eastern pacific into the CONUS….which will allow the system to scoot off to the ESE.

Behind it, possibly a weak short wave…more showers please. It will be cooler then normal a good part of next week but the longer range guidance does eventually warm it up again…..Indian Summer anyone?

Enjoy the 1st real taste of Fall!!!!

Adios Amigos…………………………………:-)

The Dweeber…………………:-)

 

PS: The update on El Nino today from NCEP is indicating some back peddling. There are doubts now whether the atmosphere will ever couple up, El Nino Style to the slightly warm waters over the central pacific. The forecast is for very weak to neutral conditions this Fall/Winter. This is “one” reason why this winter will be so hard to predict.  The issue is that there are few strong signels to go with.

 

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Research on the effects of the -AO and +AO on West Coast Weather:

The Dweebs know that there was/is a lot of chatter over the past year on the effects of the Arctic Oscillation, its Phase and the resulting weather across North America.

The big problem for us out west is that the response for the far west is “Nonlinear”.

A nonlinear relationship is a type of relationship between two entities, in which change in one entity does not correspond with constant change in the other entity. This might mean the relationship between the two entities seems unpredictable or virtually absent. However, nonlinear entities can also be related to each other in ways that are fairly predictable, but simply more complex than in a linear relationship.

In the case of the AO teleconnection, for the west, it appears that it is “the strength in the phase of the AO” that is needed to bring about a more a linear response out west. This is not the case for areas east of the Continental divide where the response of the Arctic Oscillation is more linear to the Eastern half of the country. In other-words, in the case of the negative phase of the AO, and for example its effects upon the Great Lakes region of the country, odds are pretty good that it will be both colder and stormier than normal.

 

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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.

Its October 1st…..Its warm and the weather to remain that way through Midweek…..Cooling Starts Thursday, Then into the following week…..Showers still a Possibility Early Next Week…..Fall Color Beginning to Come On Stronger Now in the High Country……Plan Your Eastern Sierra Fall Color Trips Soon!

Nice Block developing over the Eastern Pacific with Banana shaped subtropical ridge giving us some pseudo Summer Weather to enjoy.

Current developing block is being forced by a deepening Aleutian low with the Canadian model 500mb heights down to 511dm by Friday AM….While the 00z Monday GFS is not nearly as deep with heights same time about 100DM higher. Both the Canadian and GFS guidance shows the pattern out in the pacific to become progressive with time as the upper ridge now forming near 140west moves into the inter mountain west later next week. However, looking that the 00z ECMWF, the pattern remains blocked on the deterministic run. However its ensembles are slowly progressive at the least. The Dweebs feel that a slower progression is probably the way to play it for now.  The means that longer term forecast is based on the assumption that the Cutoff low will hang around a bit longer next week and may actually come further south like the EC……It will be fun to watch.

Through the process….we get at least one, possibly two low pressure system’s that will all bring cooling and the chance of showers…maybe that dusting?   After all, the first system does have a (500mb-1000) thickness pool in the 550s. There maybe a sheering system effecting the area about mid month.  After that….it looks like we may ridge up and warm up again to above normal by mid October standards.

PS…Fall Color is beginning to come on strong now in several areas of Mammoth and June Lake…

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Research on the effects of the -AO and +AO on West Coast Weather:

The Dweebs know that there was/is a lot of chat over the past year on the effects of the Arctic Oscillation, its Phase and the resulting weather across North America.

The big problem for us out west is that the response for the far west is “Nonlinear”.

A nonlinear relationship is a type of relationship between two entities, in which change in one entity does not correspond with constant change in the other entity. This might mean the relationship between the two entities seems unpredictable or virtually absent. However, nonlinear entities can also be related to each other in ways that are fairly predictable, but simply more complex than in a linear relationship.

In the case of the AO teleconnection, for the west, it appears that it is “the strength in the phase of the AO” that is needed to bring about a more a linear response out west. This is not the case for areas east of the Continental divide where the response of the Arctic Oscillation is more linear to the Eastern half of the country. In other-words, in the case of the negative phase of the AO, and for example its effects upon the Great Lakes region of the country, odds are pretty good that it will be both colder and stormier than normal.

 

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.