Mammoth Weather Outlook

Storm winds down today…Moderate AR still on tap for Monday….Pattern beginning to show signs of Fatigue…


Storm system over night has brought about 4 to 7 inches in town with 6 to 14 inches on the mountain.  Snowfall rates will taper off this afternoon with mainly light amounts. Next storm is the biggie with some 5 to 6 feet possible over the crest by Wednesday AM.  Up to 2.5 to 3 feet is expected in town. The snow level will rise to 8000 by late Monday afternoon and so it looks to be all snow or a period of very wet snow for the Town of Mammoth during the warmest part of the event.

The outlook shows a more moderate storm after the Monday AR-Tuesday storm Friday night into Sunday, followed by another stronger system with multiple feet possible with a moderate AR, late Sunday through Tuesday.  A break is possible the 18th Wednesday with a weak short wave ridge. Then a more significant change in the pattern is touted by this mornings Deterministic 12Z GFS with significant ridging developing at 140 to 145 west turning the pattern into more of a NW  slider pattern. This usually brings lighter snow fall amounts and colder weather for the 18th and 19th then a longer break possible. There after, more of a drier pattern with NW sliders beyond….


This is an outlook subject to change…………………


Detailed update later today from the Dweebs!

Beautiful Day Friday with very light snow Saturday….Massive Storm with 1-2 punch beginning Sunday with strong AR Monday…..Snow Levels tricky!!



Quick update:

No change in the forecast for today. Flat light conditions, no significant snow today. Winds picking up over the upper elevations.

Next wave comes in tonight with light to moderate snowfall.  Expect about 6 to 12 inches over the upper elevations by mid day Sunday. About 3 to 6  inches in town. Wave should be through with diminishing winds aloft early Sunday afternoon. Decent travel in the afternoon. High today 35 low 25.  High on Sunday 35…

Next storm is the wet AR for Monday.  Moist surge moves on shore about mid night Sunday night and increases early Monday AM. Snowfall rates increase Monday AM after midnight Sunday.  I have questions in regards to the snow level Monday afternoon as the freezing level goes up to 8000 to 8500 feet near Yosemite. The Snow level forecasted by NWS is at 7000 feet.  Possibly the AR does not get that saturated air this far east?  Will update snow levels tomorrow afternoon for Monday.  FYI;  California Nevada Forecast Center (CNFRC) is forecasting shows that during the AR and including the cooler part of the storm Tuesday, Yosemite gets 6.62 inches of water and Huntington Lake gets 7.15 inches of water. That’s about that 4 to 5 foot storm for the upper elevations for that storm. Add on the Sunday system for about a foot…..5 to 6 more feet!


For the outdoor enthusiasts,

It is estimated that a break in the weather may occur mid-day Wednesday through possibly Friday with Sun, periods of wind and mainly periods of very light snowfall.

Longer Range;   (Outlook, highly subject to change)

The pattern is beginning to change a bit later next week in that pressures aloft are increasing over the Rockies. This will slow the advance of weather systems later next week as well as weaken a few including the Friday night system into Saturday night. 14th and 15th.

Beyond that weekend the storm track is shifting more to the north, and so snowfall will be less with each storm, beginning around the 18th of January. Again, this is subject to change…  (See Day 8 Means below) See Split Flow Day 8.



Dr Howard and the Dweebs…………………….:-)



Beautiful Blue Bird Day!   Weak ridge of high pressure that moved in last night will be with us today and ensure a wonder day for Skiing and Boarding.  Mammoth Mt now Boasts 11 to 15 foot base. 37 inches of new fell over the past 3 days.

Weather pattern continues active with a small system for Saturday, bringing an inch or two of snow and moderate wind.  Winter storm warning are hoisted beginning Saturday at 4:00AM mainly for wind. The tempo for snowfall will increase Saturday night and especially Sunday as a moderate storm moves into the area for Sunday. The NEXT STORM is a powerhouse.  It contains a strong atmospheric river (see Graphic’s below), beginning Monday morning through Monday night. Copious amounts of precipitation are expected to fall with the snow level rising to 8000 feet Monday.  3 day Snowfall amounts will be in the 4 to 7 foot range over the higher elevations Sunday through Wednesday AM. There looks to be a break Wednesday into Thursday.  Another storm is possible late Thursday through Friday.

As a note, there are several surface lows rotating counter clockwise around the mother low early next week. However, there are two surface lows that make it onshore early Monday Evening and another later Tuesday AM of significance!



Next AR moving in tonight with Heavy Snowfall expected toward midnight into Thursday AM….There will be a break Friday/Ngt with light snow first half of the day Saturday…..

This appears to be the year of the AR as the Scripps graphics shows 5 ARs between today and mid month. (See graphics below) of course the data can change but this is today’s snap shot.   The screaming message this mornings says that there are still a series of storms out there that have the potential of dumping a lot of rain and snow over Central and Northern CA. Snow levels will fluctuate and there most likely “will be periods” of rain or very wet snow in town over the next two weeks.

Now that soils are saturated in many areas of Central and especially Northern CA, the possibility of significant flooding along main stem rivers will be increasing as we head toward mid month.

For Mammoth, our history shows local street flooding to be the main issue during especially warm wet ARs along with avalanches. At the moment, the ARs appear to be cold enough for snow in town.  Lets hope it stays that way! However, it is a very good idea to make sure that drainage in the lower elevations of town is free from ice and snow as best as possible. Historically, areas especially susceptible are in the Sierra Valley Sites subdivision and parts of Old Mammoth along the Mammoth Creek.

Below is a snap shot of the graphic from Scripps on the AR forecast. The strongest AR’s can be associated with the warmest temps. Another graphic is from the GFS ensemble from last nights run covering the period today through first week of February for the quantitative precipitation forecast

Additionally, precipitation is 155% of normal on the west side of the our portion of the Sierra.


This mornings deterministic run for the gfs/ 12z 1-4-2023