Weather update shows a nice day today with minimal daytime convection in the late afternoon…  Highs in the mid to upper 70s…Then cloudy weather developing Friday with showers and thunderstorms possible in the afternoon and evening hours….Upper jet and its front left exit region will focus lift over the Owens Valley Friday afternoon. Thereafter, a cold front will move through Saturday with showers, and some thunder possible. Gusty winds will increase Saturday and high temps will cool to the 50s. Snow Showers possible above 9000 to 10,000 feet Saturday with lowering snow level to elevations in town, Saturday night and Sunday AM.  Sunday will be the coolest day with highs in the 40s….Be ready for a freeze Monday AM with lows in the 20s…..

Remember….In Mammoth, climatically speaking…the last freeze is usually Fathers Day.  That’s why Fathers are so Cool!!! 😉


Latest 12Z Monday, NAM shows an upper trof off the coast of California today along with the Rt Rear entry region of the the upper jet focused upon the Central and Northern part of Mono County’s Sierra. So today’s chances of rain, thunder and showers will be from about June Lake/Mono Lake, NW along the Sierra, then east across Alpine County to the Nevada border. The 3 KM RRRR shows this well.

Expect about 7 degrees of warming Tuesday and another 2 to 3 degrees of warming Wednesday.  Wednesdays weather looks more interesting than Tuesdays with more instability due to a combination of warmer temps and some upper divergence from the upper Cut Off off the coast of Northern Baja. Thursday convective outlook is presently weaker….

The Cut Off Low:

This Monday mornings 500MB 12NAM shows the upper trof being cut off in its base from the westerlies by 00z Tuesday.  This cut off will remain quasi stationary late today, Tuesday and Wednesday. Wednesday should be the warmest day of the week for Mammoth. There is at least weak upper divergence over the Southern Sierra, and SE flow, northwest to Southern Mono County….Thus I expect a more active afternoon for convection.   Thursday’s 500MB GFS shows the upper flow backing to the south while the upper cut off begins to be picked up by an approaching GOA trof.  Friday might be the day!!  Upper Cut-Off lifts NE into CA with Stronger Upper Divergence along with showers and thunderstorms and much better areal coverage.  However, a lot depends upon where the Cut Off moves inland.  If it lifts NE toward Santa Barbara, then good rains and thunder will develop. If it move inland near the CA/MEX border, showers will be considerably less.  Stay Tuned!!….  Remember, a cut off low is a weatherman’s woe…


Longer Range:

We usually get one good cold system in June, before the Summer Weather really sets in…  This year looks to be on target for the same.  The upper kicker that boots in the cut off will begin to affect our Sierra Weather this weekend. It will breeze up and cool down.

The big question this Morning, is which model is going to be correct during the week 2 period. (Next Week)  The GFS has a vigorous cold trof capable of producing at least very light amounts of snowfall Later Saturday Night or Sunday AM……ECMWF has some reference to that but not as strong…..130Knot  upper jet comes in Early Sunday Am so breezy and quite cool for this time fof the year Sunday followed by Freeze Monday AM….>>>>   Stay Tuned!!!!


Expect rapid warming next Tuesday and Wednesday…


Dr Howard and the Dweebs………………….:-)