Archive for June, 2020

Last week of Spring begins with breezy conditions Monday through Tuesday and ends on a calm note with above normal temperatures next weekend as Smooth Spring hand-off expected to Summer……

Fathers Day:


It’s the first full day of Summer and it feels like it.  Temps today should hit 80 degrees in Mammoth.  At 12:00PM a light zephyr had begun.  For those that have never experienced Mammoth in the Summer, I can say without reservation, that Summers in Mammoth are nothing short of heaven on earth!  For the most part, Summers are dry, with low humidly.  Days are sunny with the exception of a handful of thunderstorm days.

The weather outlook this upcoming week will be fair with high temperatures some 10 degree above normal. As pressures build aloft this weekend, there will still be an afternoon Zephyr, A subtropical high will build aloft over the state for lighter afternoon breezes Monday and Tuesday. Afternoon convection will drive mainly isolated late afternoon thunderstorms Mid Week.  In the longest range, an early Summer Trof will bring some 10 to 15 degrees of cooling the end of the month into the first few days of July. This Trof looks to bring gusty winds fire weather concerns.  Nighttime lows may back down into the 30s for a day or two. However, highs will still reach upper 60s and low 70s.  All the global models have this Trof for the 29th, 30th and first few days of July.


The westerlies continue to their recession to the north this week as Spring shifts to Summer this weekend. These are the very longest days of the year……  Sunset averages about 5:39 PM with Sunrises at 5:30 AM. Saturday’s daylight is 15 hours and 18 minutes. The Summer Solstice occurs at 2:44 PM Saturday Local time.

500MB charts and progs show a slow migratory short wave over the Pacific NW  Monday and Tuesday with 130 knot upper Jet NW/SE through far Northern CA. Expect breezy weather today through Tuesday. Wind advisories are hoisted for Mono County Lakes,  3:00PM Monday through 10:00PM Monday night. However, because the weather system is so far north, little if any cooling is expected the next few days….  Last weekends storm look to be the last of the season as the westerlies continue their retreat to the north….


Cut off lows may still enhance afternoon convection, the next few weeks for afternoon thunderstorms, however, afternoon temps likely to stay warm!!  70s….


Dr Howard and the Dweebs…..:-)



Weather pattern of variablity likley to continue another week…It will be cooler this weekend after a Troughs Passage…Then warming Sunday into following mid week….Another trough is likely the 2nd half of next week….

Seasonal temperatures are expected the next two days as short wave ridging build over the area.  Another late season trough descends from the GOA Friday bringing gusty winds and cooler temps Friday through Saturday.  Winds may reach advisory level Friday afternoon and night.  Temperatures will cool some 10 to 15 degrees between Thursday and Saturday. However, this cool down is not as strong as last weekends.  Lows at night are not expected to reach freezing over the weekend at resort levels but may get close to that in some remote areas along the highway 395 corridor Sunday AM.

Looking at the climate signals, there is a slow moving Kelvin Wave entering the western pacific. This is thought to be causing a false MJO signal by its air sea coupled convection over the western pacific.    Week two models sill show a slight weakness in heights at 500 mb over the far west during that period, meaning that temperatures will average closer to normal at resort levels as opposed to the coastal sections where it may get toasty next week.  Normal highs for Bishop are upper 80s now and for Mammoth and June Lake, upper 60s.  Seasonal temps are expected today.


Expect windy weather to develop Friday and especially Friday night as a short wave Trof moves through the area. Highs will cool to the low 60s on Saturday and this system is accompanied buy some initially-dry air. So Fire weather concerns are highlighted Friday and Friday night.  The is a 20% chance of showers Saturday over Mono County. expect rapidly warming temps Sunday into Tuesday next week.  Longer range guidance is still flirting with the idea that next weeks Trof  may be the last of Spring.  The ECMWF has hot subtropical ridge over us by the 25th of June while the GFS has a digging trof coming out of BC, Can.   So…. too soon to say Spring is over.

Dr Howard and the Dweebs……….:-)






The weather will be variable this week….Chance of Showers and Thunderstorms…..Then Breezy and Cooler over the weekend….Even a slight chance of some snow showers late Saturday or Sunday AM….


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………………….:-)