The first real shot of Great Basin cold air this Fall will head into the high country Tuesday morning as a North-Central Great Basin Slider moves into the Rockies by Mid-Week. No doubt this will bring some good snows to the Central Rockies. Light to moderate winds will pick up in Mammoth Monday with Breezy WX continuing through the night. The system is moving more to the east (progressive) and not deepening all that much, and so the NE up-slope from it will be short lived and benign. Nevertheless…..some of the coldest temps this season will develop over the Mono County Valleys, with lows well down into the teens by Wednesday AM. Strong inversions will develop as well by Mid Week as heights rise again over the cold air trapped in the valleys Wednesday into Thursday.

The following Eastern Pacific System will split as it approaches the west coast. The timing of it coming through California is the 29th. The biggest problem is see is that:

1. The Dominant upper level high has been centered about 160E…well too far east.

2. The energy coming off Asia continues to be split with dual storm tracks.

3. This mostly results in the energy coming into the west coast split as well.

4. This is forecasted to continue into Early November.

Some forward thinking….

Now even with a split flow pattern, the Sierra can get some snowfall. That is if the resulting split is in the right spot to put the south Central Sierra in the Bulls-Eye. That is always critical.  We want the upper closed low to be centered very close to us!  Are the Dweebs asking for too much? Never! Will that happen? Not according to both 6 to 10 day and 8 to 14 day outlooks. However, that level of skill is always diffacult time wise that far out and especially this time of the year.

What’s MJO up to?

MJO is currently in Phase Space 2. (Indian Ocean) and favors the current storm tracks; IE Split Flow

Where is it headed?

Through the end of the month it will be pretty much stalled out and weaken in Phase Space 2.


When will it be in a more favorable position?

Hard to say as the ensemble members have a wide disparity as seen in the chart below, and MJO is forecasted to weaken substantially, so its effects may not be relevant. However with that said…it does move weakly into Phase space 4 by the 2nd week of November.  So it may be that a storm of significance moves in to the Mammoth area the end of the 1st week of November or the 2nd week of November. Will update when we get closer to that time frame.



It is interesting to note that the large pool of Warm SSTA’s that spent the Summer north of Hawaii redeveloped westward at 168E.

( That happened last Fall) Coincidentally, that is near the mean position of the highest heights over the pacific.. The rest of the warm water pool has disapated north of Hawaii with some of it along the west coast from Northern Calif northward to the Washington Coast. There is a very cold pool along 140W between 40N and 50N. And of course there is plenty of warmer then normal water from Japan to Kamchatka, Russia. As a note the warm water pool west of the date line is a bit west of where it was Fall of 2010 this time.

More comments…..

In conclusion…the overall the weather for Mammoth Lakes will continue to be highlighted by above normal heights and warmer then normal temps into the month of November with a quasi eastern pacific split flow pattern at times.

There is a slight chance that the end of the month system (29th) may bring a few light showers or sprinkles but not much more if any.

Tomorrow Sunday will be the last Sunday of temps in the upper 60s in Mammoth… some 15 to 20 degrees of cooling will arrive this Tuesday into Wednesday…then moderating temps back up to near 60 by the following Saturday.

Be sure to finish all outdoor painting/staining this weekend…..then blow out sprinkler systems by this Monday… hard freeze conditions will develop Tuesday/Wednesday.

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.