A weak upper level trof in the mean shall continue over the west coast through the end of this week. The remains of last weekends storm (trof) is expected to come through today, initiating scattered showers and possible thunder. Freezing levels are about 11,000 feet, so it should be rain showers in town and snow showers up on Mammoth Mt later this afternoon and evening.  As temps come up this week, that will steepen lapse rates and so afternoon convection and diurnal showers may occur just about any day this week. Normal temps for Mammoth at 8000 is 70 degrees now. It is obvious that we have been well cooler then normal since Winter. That may be about to change!

La Nina is dead….However the negative phase of the Pacific Decadal Oscillation (PDO) is very much alive and going strong!

The PDO effects California WX differently depending upon the phase that it is in. Warm water over the central pacific (+SSTA) and persistent cold water  (-SSTA) along the west coast and Northeastern Pacific are classic signatures of the negative phase.  The negative phase brings more storminess to California, often times making for longer cooler wet seasons that persist even into June. The upper trofing that we have been experiencing will likely continue to some degree through June. However it will eventually pull to the north as the westerlies weaken through the month of June and July. It is expected that we will remain in this Cold Phase for some time now. Highlights will be a longer June Gloom season this Summer for Southern California, possibly much like what happened last Summer.

Will we turn warm next week?

Here is what the Dweebs are looking at:

First of all Summer has really returned to the mid south, south, then eastward to the Southeast sections of the CONUS for sometime now.

For several runs now the American Global Forecast System (GFS) was been trending toward a large scale change in the pattern for the far west. They weaken the westerlies, and at the same time, lift the long wave trof that has been over the far west seemingly forever, NE over the northern plains. The westerlies actually retreat up into Canada by the 16th! At the same time the Northern Mexican continental high retrogrades while building northwestward into the California the 18th into the 20th. This suggests that temperatures will remain much below normal this week to just somewhat below normal by the weekend. I am expecting low to mid 60s this weekend at 8000 feet. Temperature will actually approach seasonal highs in about a week. (70). 

Thereafter, it gets interesting as the GFS longer range shows 1000-500 thickness building to 582DM by the first day of Summer. That is low 80s in Mammoth and a 100+ in Bishop on the first day of Summer. 

With all this said, the ECMWF ( European) has been much slower or at the least, much less aggressive toward the trend to Summer temps.  However the Dweebs will say that the ECMWF is just beginning to trend that way in the last few days.

From the CPC…..both 6 to 10 day and 8 to 14 day charts are sticking with persistence showing the weather cooler then normal through nearly the first day of Summer for much of California. However with that said, they are giving their forecast only a 3 on a scale of 5 for confidence at this time. (Average)

At the moment, the Dweebs even though we are in a -PDO are banking on a FAB Father’s Day!

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.