Wet portion of storm still on its way with high freezing levels well advertised.  Freezing level remain about 9K Thursday Mid Morning through 4:00PM then fall rapidly over night.   In a saturated air mass, the snow level is about 500 ft to 1,000 feet below the freezing level.  Uptown will have the best chance of accumulations tomorrow PM with snowfall likely Thursday night. Downtown Mammoth will most likely see rain or rain snow mix until about 9:00PM -10:00PM Thursday.



Improving weather Friday PM with fair weather Saturday.   THe is a smaller system that will bring more snowfall Monday with generally light accumulations.

Long wave hemispheric pattern shift to positive phase of PNA, with Retrogressing of upper high to the Dateline and Eastern pacific Trof north of Hawaii;  Ridge over the west and Trof in the east….:-{



Winter Storm Warning above 8000 feet 400pm Wednesday through 4:00AM Friday. Accumulation’s 1 to 2 feet in the upper elevations of the Town of Mammoth 8000-8500 between Later Thursday Morning and Friday AM.

Between 30 and 50 inches is expected on Mammoth Mt above 9000 feet by Friday.

Snow level lowering to 7000 over night Thursday and 6000 Friday AM


From Tuesday:

Here we go again!   What a difference 24 hours makes!  Yesterdays small “AR” has grown in size over the past 24 hours aided by a tropical low along 20N and 130W.  This system’s moisture is being picked up by all global models to add to the fetch from Hawaii. It all adds up to a forecast for a Bonanza of snowfall for the higher elevations. This will certainly kick-start the ski season for Mammoth Mt as up to 4 feet of sierra cement is expected over the Sierra Crest between Wednesday Night and Thursday night.

Here are some of the details:

  1. PWAT up to 1.5 inches is expected in the Bay Area Wednesday night.
  2. 500MB/850MB winds are forecasted up to 50-60 Knots. (Orographics will be maxed out!)
  3. Thus, this is no longer a small AR


The snow level will range from 9000 to 9500 feet Wednesday night and come down Thursday morning to between 8000 and 8500. Snowfall amounts in the upper elevations of town may be in the 12 to 18 inch range. The snow level will lower into the lower elevations of town by Late afternoon Thursday.  If by chance the storm slows down Thursday night and continues into Friday AM, the Town could pick up quite a bit more. (I will have more certainty on this Wednesday AM)

Best guess is that Mammoth Mt between the Main Lodge and the crest will be in the 2 to 4 foot range. If by chance the European model is correct, there would be more snow top to bottom.


There is another AR or two looming in our future for Monday of next week and the following Wednesday/Thursday.  Looking at the current GFS set up vs. The ECMWF next week, I noticed that the upper ridge position is currently at 158W. During the next AR, the upper ridge retrogrades about 10 degrees westward to about 168W. The short wave in question begins to split but then consolidates and lifts north as it comes on shore. That would effectively shift the colder portion of the pattern, well to the north of us, leaving us with a Small to Mod AR.

The New12z ECMWF has a different set up and has less emphases on the AR for Monday but instead makes a big deal about what is to follow the day before Thanksgiving. By comparison, the ECMWF shows Mondays system less about major moisture and more about colder air, as the trof in fact does split. Its solution is all about shifting more energy further south so that LA may get rain.

Now I will just mention a bit about the Wednesday before thanksgiving system.  Potentially it is a Major AR! In the subtropical branch, the upper STJ extends back to the dateline this early Tuesday and both the polar and subtropical jets are confluent west of Northern CA Tuesday with Jet O’ genesis to 180 knots!.

The AR comes in underneath the subtropical portion assisted by the Rt rear entry region. Preliminary PWATs are showing up as 1.75 inches near Monterey, CA….close to 300% of normal and STD of +5 Wednesday evening.   This is a long way out but fun to see this Forecast run.  The Freezing level is about 10,000 which is not too bad considering….


Stay Cool…Winter is just beginning!


Dr Howard and the Dweebs……………………:-)