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…


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.