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………………….:-)

Fair Weather Ridge will provide warming the next two days with the next weather system taking a trek a bit further north……Weekend looks unsettled and breezy with light snowfall…


(Get ready for the storm that will not die)

Amounts over a 6 day period beginning Tuesday will range from 2 to 5 feet. The storm will begin on the warm side but will chill through the week….

This is a series of waves attached to a mother low that will park off the coast next week.

Still keeping the faith for a miracle March!   (176 total inches)



Thursday AM:

The Subtropical jet is dominating the WX pattern with periods of gusty winds and unsettled weather. This is expected through Sunday. Although snowfall in the Town of Mammoth will not be heavy, there may be 3 to 5 inches of snow with some 6 to 12 inches over the sierra crest between Saturday afternoon and noon Sunday. The snowfall will be heavier and more moisture leaden than recent storms.

The mid-week storm is still looking good with both subtropical and polar jets being coupled. I expect several feet of snow during the second half of next week. Although there are still several storm’s in the picture this month, the 15 Day ECMWF EPS shows up to 7 inches of water or an average of 70 inches of snow by 23rd. We will need quite a bit more to get close to the 176 inches so not looking all that promising but still possible.  The good news is that the bulls-Eye for the 15 days is over the Northern part of the Southern Sierra……


The Dweeber……………………..:-)


Wednesday PM:


Here is the latest QPF update for the next 10 days from the Deterministic models for the area around or just west of the Mammoth Crest:


GFS:       5 inches  10:1   50 inches of snow

ECMWF: 7 inches  10:1  70 inches of snow


PS: The official snow total at the main lodge from the weekend storm was 50.5 inches.

So 125.5 more inches of snow to tie the miracle march of 1991. That may be tough…we need at least 2.5 more storms like last weekends to get close or more smaller storms!


Tuesday Afternoon:

ECMWF (European Model) Coming in pretty wet now for the Monday night-Friday storm next week.  QPF suggests 6 to 7 inches of precip…..or 5 to 6 feet over the crest by Friday the 16th.  Again, the Trof and its associated polar jet to become confluent with subtropical jet and its environment Monday night, then on and off through Friday. Should make for some explosive Jet O’ Genesis!  Yes..this is another slow-moving developing pattern.  This system is not as cold as last-weekends storm but may finish some what cold…  The Dweebs still think the Miracle March is possible…. Need 176 inches at Main Lodge in March to tie it….


Mammoth will enjoy a few days of spring like temps with highs well into the 40s today and Wednesday. As the upper ridge pushes east, subtropical high level cloudiness will overcast our skies Tuesday night and Wednesday. The next few systems this week look weaker now with only some light snow showers expected Thursday evening. Temperatures will cool this weekend back into the 40s and there will be windy periods over the Sierra Crest.  Snow showers are possible Friday through Saturday with the most organized system heading more north now and weaker at that. Expect anywhere between 3 and 6 inches of snow top to bottom through Sunday night with 1 to 3 inches in town.

Next storm will be early next week and it still looks strong with the possibility of footage in the high country. Some of the new model solutions tend to phase both subtropical and polar jets together by Mid-Week.


Dr Howard and the Dweebs…………………….:-)

The new week is highlighted by a change in pattern leading to more seasonal temperatures as our cold weather gives way to the Subtropical Jet…It will be very breezy over the higher elevations Wednesday and Thursday with the slight chance of some light snowfall Thursday and a better chance Saturday Night…..

Monday AM:

Only changes this morning to the discussion below is to highlight the potential of “AR” moisture from the subtropical jet later this weekend.  There is a trend in the GFS of pushing a portion of this off shore AR further north up into Central CA. At the moment it is too soon to forecast any significant AR with any certainty other than to say that a more dynamic system will tap deeper moisture from an AR off the Southern CA coast this weekend….The Dweebs well keep a wary eye on that.

The other change is in the timing of the main precipitation push, which now highlights Saturday Night into Sunday instead of Sunday night. This late weekend storm has the potential of bringing several feet of wetter snow to the upper elevations through Monday with nearly non stop snowfall possibly between its exit and the timing of the passage of the main mother low which may slow down through the 15th and not come through until Friday night the 16th.  We could see another 5 to 9 feet over the crest should all of that happen……Miracle March anyone?

Another comment…..Some times patterns will repeat themselves…Watch for another cold Low that may form off the coast of the pacific NW tapping Arctic Cold that may try to repeat what happened last weekend for around the 19th of March. It is later in the year but well see what shapes up….

For those interested in the snow level….It looks to range from 7500 to 6500 feet later this week. The following week looks to be colder with lighter fluffier snow toward mid-week with lower snow levels.


Dr Howard and the Dweebs………………..:-)


After last weekends monster….The weather will be more tranquil the next few days. There will be periods of wind, clouds and some showers possible by mid-week.  Daytime highs will moderate well into the 40s Tuesday and Wednesday with nighttime lows in the teens and 20s.

Tonight’s new model runs show an interesting analysis at 00z Monday.  Namely, an upper height anomaly that stretches from the Philippine’s, northeast along most shores of the western pacific eastward across the dateline to the Gulf of Alaska.  I see no significant troughing anywhere over the pacific at this time. The pattern highlights two distant polar and subtropical jets. The Subtropical jet is being enhanced over Hawaii and the polar jet around 50 to 55 north just north of the Aleutians, Hawaii looks to be in for some good rain the middle of this week!

The upper polar jet looks to be doing some wave breaking Wednesday and this will cause the current cut off low along 140 west to become stretched out over the next 3 to 4 days. This process will enhance the subtropical jet in its underbelly and extend it to the California Coast by Tuesday/Wednesday. Precipitable water does increase with isotropic lift expected over the colder air. So the chance of mainly light precipitation is expected Thursday into possibly Friday. Again it appears to be quite windy Wednesday over the Crest.

The pattern by the end of this week does become more amplified. The key positive height anomaly amplifies near the dateline and becomes positive tilt over the weekend. This allows the deepening of a significant trough over the Eastern Pacific which kicks out the remains of the old cut off low next Sunday night and Monday. The suggestion is that some decent snowfall will result from that storm. Nothing like what we had last weekend, nevertheless the chance of some moderate snowfall.

Longer Range:

Eventually the large scale Trof that develops later this week comes though itself about the 15th of March with the possibility of a major storm.


Dr Howard and the Dweebs………………………:-)