Major AR Event to pretty much Lock in a Miracle March for the High Country Mid-Week…Snow then rain then Snow for the Town of Mammoth…..

9:20am Thursday:


Back edge of the AR has moved through the Bay Area and progressing east.  As of 8:00AM, Mammoth Pass has picked up 3.5 inches of water EQ with another 3 inches in the bucket expected over the next 24 hours.

Colder storm off the coast of the pacific NW is digging SE and becoming negative tilt. It has picked up the southern stream trof and is the kicker that will bring in its remains tonight…The current AR is now pushing into Southern CA increasing rainfall rates there.

By early Friday AM a dry slot comes through, diminishing cloudiness and gives us a pretty nice Friday afternoon except for wind. The upstream cold core kicker trof will open and come through Northern CA Saturday night. Ahead of it will be light snowfall for our area. Amounts look lighter than my previous post. RFC has backed off and now reports .59 inches of QPF for Yosemite. Even at 15:1 that would be about  9 inches over the crest. Best guess for the Saturday storm….2 to 4 inches at 8000 feet and 4 to 7 inches over the upper elevations by late Sunday AM. Snow showers may persist for a while into Sunday afternoon but little if any accumulation is expected Sunday PM.

Longer Range shows ridging building in Mid-Week with Gusty Easterly Winds over the Mammoth Crest Tuesday into Wednesday with quite a bit of warming Wednesday into Thursday. It looks dry and warmer Tuesday through the following weekend.


It will be cold over the weekend with highs in the low to mid 30s in town and lows in the single digit and teens across the county.


The next possible stormy period will be beginning about April 5th or 6th….


Dr Howard and the Dweebs……………….:-)





9:30Am update

New guidance from the California Rivers Forecast Center shows the freezing level dropping quickly Thursday morning and that precipitation will be all snow to the lower elevations of town by Noon Thursday. If this is true then heavy snowfall can be expected to all elevations of Town Thursday afternoon.  The same forecast shows between 5 and 6 inches of water EQ over Mammoth Pass between today and by Thursday night. This is in addition to the nearly an inch that has fallen so far.

Other changes; Moderate storm Saturday with up to a foot of light powder on Mammoth Mt and some 3 to 6 inches of snow in the Town of Mammoth as the freezing level lowers to 3000 feet Saturday. Light snow showers are now expected Sunday. Dry Monday…milder Tuesday….

Friday looks dry…..

The snow level in the Mammoth area will be mainly 8000 to 8500 today and up to 9000 feet for a time tonight. The snow level will come down during the day on Thursday and into Thursday night. The snow level will lower to between 6500 and 7000 by Thursday night.


Change in weekend forecast;

The models have been consistent since yesterday in deepening the northern stream trough enough to bring light snowfall to our area now….Saturday and into Sunday. Expect much colder temperatures over the weekend.

Next week look dry and milder at the moment.


Dr Howard nd the Dweebs………………:-)





Tuesday AM:

Here is the latest…..

In summery…There is a lot of moisture coming to all of the sierra

In the Town of Mammoth there could be between two and 3 inches of water equivalent.

Over the lower elevations of town (7500 ft)  I am not expecting a lot of snowfall. It will be mostly rain or rain snow mix. It may start as snow but will change to rain pretty quickly as the AR rushes in Wednesday so not much accumulation.

At elevations “Between 7500 and 8000” there could be up to a foot of sloppy wet snow.

At elevations between 8000 and 8500 there may be somewhere between 1 to 3 feet of wet snow. It is very difficult to tell whether it will be a 1.5 feet or 3 feet. You are only talking about a temperature difference of maybe 1 degree.

The main snowfall with this storm will be above 8500 feet where 3 to 6 feet is possible. The 5 to 6 feet is above 10,000 feet. (Sierra Crest)

The not so good news is that there is a large dry slot coming in behind this storm Friday and that will cut the moisture off pretty quickly Friday. So….not much influence is expected from the northern storm for Friday into Saturday night with only light snowfall expected.

What we have here in Mammoth is a weather pattern that is primarily an Atmospheric River with not much follow though with moisture from the northern branch.

It will be wet and wild the next few days!


Temperatures will be in the low to mid 40s today and mid 30s tonight…then highs in the upper 30s on Wednesday and mid 30s Wednesday night with little change in temperature for Thursday. I am expecting a freeze by Friday Morning with lows in the 20s.


Saturday there is a chance of snow showers and it looks to be a Blue Bird Day on Sunday..


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





The First major Atmospheric River event this year is shaping for Southern CA and the Southern and Central Sierra, for Mid-week. A wide swath of rich Precipitable Water will stream into Southern and Central CA beginning Tuesday night and will increase in its intensity Wednesday into Thursday. this is part of an Omega Block over the Central pacific and the eastern portion with its cut off low spinning at 140west and some 1000 west of the central coast tonight.  The Duration of the event along with its intensity suggest that orographically favored areas on the west side of the southern sierra could get up to 10 inches of water from this storm. Here in the Eastern Sierra, the west side will take the brunt of the storm, squeezing some 5 to 7 inches of water over the Mammoth Crest for a good 5+ feet of snow.  Snowfall amounts in town will vary greatly where the Mammoth Slopes area above 8000 feet will get a lot of snow through the period ending Saturday while the lower elevations of town get a lot of rain at times and not as much snow. So at times it will rain and at times it will snow at 7500 to 8000 feet.  The Nested Grid model shows the snow level lowering into town by Thursday morning….This is Faster than predicted on Sunday Morning. We still have another 24 hours to follow its progress, as the storm is still developing…. By Thursday night, the AR should be south of the state while the colder portion of the pattern with its cold GOA low digs south into Northern CA. This will bring colder lighter snowfall to the high country, Friday and especially Friday night into Saturday.



Dr Howard and the Dweebs………………….:-)



Storm System Currently moving into high country looks wetter for tonight…..Heavy Snowfall expected Tonight and most of the day Wednesday……Weekend shaping up to be cold but drier now into Monday….More snow possible next week….

Traveling over the weekend…..will update Monday night…..

Platinum Powder Alert” for this Saturday Morning

Thursday night….everything on track….. Heaviest snow fall will occur when upper flow back from the WSW Tomorrow afternoon……Eastern Sierra Blizzard….

Storm Warning through 1100AM Saturday.

Now the rest of the story…..Significant Atmospheric River possible for next Wednesday….




Wednesday AM:

After a break this morning, snowfall rates will increase again this afternoon in a colder air mass through about midnight tonight. The Dweebs expect another 5 to 7 inches in town by 1:00AM Thursday. Expect another foot on Mammoth Mt. This snow will be lighter than last night sierra cement.

On Thursday, the main cold core low will be along the North Coast as the upper jet pivots NW/SE. This sets up a windy blustery pattern here in Mammoth Thursday afternoon/night until the upper flow backs from the west or WSW Friday. Snowfall rates pick up later Thursday night and continue through Friday night. A winter storm warning is in effect for this period. Keep in mind that snowfall will be of very light density and any wind can blow it around and create poor visibility creating dangerous driving conditions. Friday is not the day to travel heading north from Mammoth.  A Platinum Powder Alert is in effect for Saturday AM with a foot or better of snow on Mammoth Mt at 10,000 feet at ratios of 15:1.  The forecast is for up to 2 feet of “Angelic Powder” for Saturday Morning.  Highs in the 20s in town and teens on Mammoth Mt.

All toll….Mammoth Mt stands to pick up 5 feet of snow over the crest….The multi storm total for the Tuesday night through Saturday AM period

Sunday may be a blue bird day. Fair as well Monday…  New storm moves in Tuesday night and the hits keep on coming….:-)


The Dweeber…………….:-)




New twist this morning in the pattern will provide for rain changing to snow later this evening then heavy snowfall expected tonight through Wednesday.  Although a Winter Weather Advisory is in effect officially, full on winter storm conditions will develop by Midnight tonight well into the day Wednesday. Snowfall amounts look to be 12 to 18 inches in town at the 8000 foot level by Wednesday late Afternoon and between 2 and 3 feet of snow on Mammoth Mt by Wednesday Night.  This is a change in the thinking from yesterday where only 4 to 8 inches was expected in town.

The “QPF”  Quantitative precipitation forecast output from the models put less emphasis on the Thursday Night-Friday storm now as far as the amount of snowfall as compared to the period late tonight through Wednesday Night. However, the Thursday Night Friday system will have lighter density snow and gusty winds,  so travel conditions may be impacted Thursday night into Friday due to blowing and drifting snow. Thus a winter storm watch is warranted for Thursday afternoon into Friday Night.

The good news is that the weekend looks pretty good weather wise. For those that want to get some light dry powder, you may find pretty good weather with some snow showers mainly Saturday. Be sure to carry chains during your Friday night trek, as the snow level will be quite low into Saturday AM.

The Dweebs expect a good 2 feet plus in town over the next 72 hours and between 4 and 5 feet over the crest….

The First half of next week should be Fab!


More snowfall is expected next week as early as mid-week…..


Dr Howard and the Dweebs……………………..:-)



New Long Wave Trough developing over the Eastern Pacific likely to persist for sometime….First system will begin Tuesday then linger into Friday with long wave reloading thereafter….

Late Sunday Night:

It is subtle, however the newer models runs seem to be developing more southerly flow with this first system Tuesday into Wednesday AM as the system is taking on more of a negative tilt.  So as a result, there is likely to be more shadowing with less snowfall east of the sierra crest. The National Weather Service has dropped the WSW to a winter weather advisory.  The main shot of this precipitation is likely over the sierra foothills and along the south facing exposures, according to this evenings guidance.

A Winter Weather Advisory has been hoisted for Tuesday afternoon beginning at 1:00PM thru Wednesday at 4:00PM

4 to 8 inches of snow is expected in the Town of Mammoth with 12 to 18 inches on Mammoth Mt by Wednesday evening.

Westerly flow returns later in the week with better orographics and heavier snowfall later Thursday into Friday.

This will cut back to some degree the snowfall totals over the next 7 days, however amounts will still be impressive….


Saturday’s light rain and snow did little to enhance the snowpack over the Eastern Sierra. However, that should change as a cold upper low sets up residence over the Eastern Pacific.  Looking the Sunday 18Z GFS, the upper tough was located about 145west with the cold core very large and expansive. So not only is this system cold but it also has a large enough pool to last several days once it gets to the central west coast.

500 MB temps now are at  up to -40C with 700Mb temps into the mid -20sC   Lots of energy!

The upstream ridge behind the cold Trof builds over the top of the system for a while and acts to cut it off. However, not before it is sets up close enough along the west coast! All forecast models indicate that Southwest to westerly flow will dominate the pattern into next Friday! So this storm becomes stationary for a while and that makes it quite unpredictable as far as the timing of the more significant waves of moisture that flow into the sierra at this distance in time. There is a lot of energy indicated by the models behind this trough (trof). The whole pattern is highlighted by a persistent long wave Trof that may last through the upcoming week or longer.  The main message here is that forecasters have been watching this storm for sometime now and confidence is increasing that we will be in quite cold and snowy pattern through this Friday or possibly longer depending upon which model you believe. a good 3 to 6 feet is possible on Mammoth Mt this week with between 1.5 to 3 feet in town by Friday

GFS has next weekend cold and sort of showery Saturday and dry weather possible Sunday.

The ECMWF (Euro) Ensemble has the Trof reloading time and time again with almost non stop snowfall through the 24th. Wowie Zowie!


Here is the long range QPF by both Models for the Central Sierra on Sunday’s model run in inches of water with snow to water ratios of at least 10:1, and at times possibly 13:1 or greater.

  1. GFS:  deterministic 18z Sunday Run the upcoming 10 day period.   7 inches of water in the San Joaquin drainage
  2. ECMWF: 12Z Deterministic has 7 to 9 inches in the SJD
  3. Sundays 12Z ECMWF EPD Control has 7 to 9 inches in the SJD while the 15 day shows some 15 inches!
  4.  The ECMWF 12Z EPD Ensemble mean has about 7 inches

The upper jet approaches our area Tuesday AM and so expect the winds to begin cranking in the early morning.


It is likely to be quite chilly by Wednesday with highs in the 30s but the coldest air will arrive next Friday into Saturday with highs in the upper 20s.


Dr Howard and the Dweebs………………….:-)