A Northern Great Basin slider will bring the first shot of synoptic scale cooling to the Eastern Sierra as the stable weather pattern of July and early August gives way to a strengthening Polar Jet in the more Northern Latts…..Fall like weather has set in over many areas north of 60 N.  The weather over the eastern sierra the next 5 days will be highlighted by periods of warming and cooling. The timing of the 1st shot of cooling will be associated with the slider later today and tonight where winds will precede the cooling this afternoon and tonight. Highs Friday and Saturday in Mammoth will cool to the upper 60s and low 70’s. Nighttime lows will drop to the 30s Saturday and Sunday AM.   The further outlook shows the Trof progressing east Monday and in it wake, a subtropical high will build back into the high country rapidly Tuesday with an equally rapid warm-up Tuesday through Thursday.  By Thursday, high temps will rise well into upper 70s. There is no rain in the outlook for Mammoth through this Thursday.

Labor Day Weekend:

Although tropical storms will track NW far off the Baja Coast over the warmer than normal SSTS, our weather should remain dry through the Labor Day holiday. Temperatures will continue to remain cooler than normal through this Monday then warm rapidly Tuesday through Thursday.  The latest guidance shows TS activity actually aiding the warm up this mid-week as the release of latent heat from it’s precipitation process helps to build the subtropical ridge north-westward through CA. This will have the effect of returning daytimes highs over Mammoth to the upper 70s by Thursday the 28th.

Both ECMWF and GFS Ensembles favor a similar TS track and upper level wind flows that are not conducive for the advection of “mid level” subtropical moisture into Central California through at least Friday….   After which both global models differ with the strength of the subtropical ridge over CA. The GFS actually try’s to break down the upper ridge Saturday into Sunday. While the ECMWF hangs on to it longer.  With that said, there may be plenty of high clouds Sunday and Monday (Labor Day) from both TS remnants/weak dynamics. especially over Northern CA if the GFS is correct.

In the longest outlook……….The CFS shows the possibility of a wet fetch of subtropical moisture between the 5th of September and the 12th of September into Central CA.  More on that at month’s end……


Have a great week and a fun-filled Labor Day holiday weekend……..


Dr. Howard and the Dweebs……………………………:-)





Will discuss the Labor Day holiday weekend outlook Sunday….