While Strong High Pressure builds off the west coast today bringing near record warmth, the next system is now looking better for a more favorable track for precipitation into the Northern and Central Sierra….Weather to become very windy for the high country Saturday into Sunday….

Friday 8:30AM Update:

Main changes to the forecast for the weekend include the slowing of the storm, more emphasis of precipitation for the Central Sierra now instead of the Northern Sierra.  QPF for Yosemite is about 1.5 inches of H2O eq.  Mammoth Mountain is store for at least a foot of freshes over all. The upper mountain may experience some rain-snow mix with the onset of the storm’s precip Sunday. The freezing level is quite high at 11,500 at 10:00am Sunday, but will fall to 10,000 feet by 4:00PM Sunday. The snow level will be about 1000 feet below the freezing level. Expect precipitation over the upper part of the mountain will change to all snow during the afternoon Sunday while the lower elevations will experience most likely either rain-snow mix or very wet snow by late in the day….  The strongest winds will be Sunday.  These winds will be strong enough in some areas to cause some damage along the highway 395 corridor Sunday.   The colder portion of the storm will arrive for the most part after midnight Sunday with the freezing level crashing later Monday morning. Snow will begin to accumulation in the Town of Mammoth Monday morning with a plow needed during the day Monday. Between 3 and 6 inches is expected in the Town of Mammoth Monday. Highs in Mammoth Monday will be in the upper 30s in town.

Storm behavior:

  1. Storm will be moving into a record warm air mass,  Pressure gradients will be very steep and winds will be strong Sunday as a result.
  2. The trof will begin splitting Sunday with a closed center forming Sunday night well west of the Bay Area. The split will have the the effect of developing the bulls-Eye of precip further south over the Central Sierra. The closed center will come on shore over Monterrey and Mammoth will end up on the NE quad of its upper divergence. So Mammoth will greatly benefit from this change of the behavior of this storm. It would not surprise me if we got 1 to 2 feet on the upper mountain, but the forecast is for a warm storm 1st that will begin as rain on top of the mountain then change to snow within hours. The slowing of the storm and its closed center will allow a period of upslope Monday which will favor the Town with its easterly flow, and could prolong precipitation well into Monday.
  3. It will be much cooler after this storms passage with seasonal temps for Mammoth. Highs in the mid 40 and lows in the teens and 20s.

 

Longer Range:

Another splitting trof will effect the high country mid-week but will be dry. There is the chance that a closed low will develop from this storm off the Southern CA coast and become stationary, only to be picked up by a stronger Trof the end of next week…..Stay Tuned….the Dweebs got you covered………:-)

 

 

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Although the Thanksgiving Holiday will be much milder than normal with a late November Heat Wave for the southern half of California, the next storm system this morning is showing up to be a potentially better storm than what was indicated the past 5 days for the period Sunday through Monday. The upper jet’s right rear entry region now favors the Central Sierra later Sunday night into Monday morning and the QPF by both ECMWF and GFS has this system showing the potential of bringing significant snow over the upper elevations later Sunday into Monday night.  Additionally, both Global models the ECMWF and the GFS  are more in line with the storm coming through in two parts. The first part with feature a warmer system Saturday and Saturday night with strong winds and the second portion colder for late Sunday afternoon into Sunday night. The models are also consistent in showing the snow levels falling rapidly behind a strong cold front early Monday morning. Although this system is still some 4 to 5 days away, moderate amounts of (6-18 inches) are showing up as a possibility for the very early next week period by the two global models this morning.

Again the Dweebs want to emphasize that the antecedent conditions of near record warmth prior to the weekend will precede this systems arrival.  Thus, exceptionally strong winds are possible to develop Saturday into Sunday over the high country.

In the meantime, enjoy the beautiful holiday weather this week. Expect highs in the upper 50 to low 60s, with lows in the 30s Wednesday through Saturday with winds coming up Saturday and rain turning to snow Sunday through Monday AM.

 

Happy Thanksgiving to all from

Dr Howard and the Dweebs……………………..:-)

High pressure will build over the far desert southwest for a dry stretch of weather for the Central and Eastern Sierra…The following week (Mon-Tues) looks unsettled with the possibility of more snowfall….

Tuesday AM:

Models Weakening southward push of Mondays weather system. Wind, Cooling  and showers likely with light accumulations if any…..expected this far south.

 

Monday PM:

 

After a week that will become increasing warmer then normal over the state, the best chance for some snowfall will be next Monday and Tuesday. The system is likely to be very windy given the antecedent conditions of super warmth by that time. At the moment a blend of the models suggest that the storm will likely favor Northern CA. Its effect upon the South Central Sierra is expected to be light to low end moderate. No AR is expected with this system and thus it should be a much colder storm.

 

Dr Howard and the Dweebs…………………:-)

 

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A strong ridge of high pressure currently over California will continue to build this week with some very warm temps by Thursday. The unusually warm weather will cool the following weekend with a storm nearing the central west coast toward mid-week.  The longer range and even interseasonal outlooks are laughable as it appears that the Hemispheric Pattern is still trying to figure out what it wants to do or be.  I know that this is driving the long-range forecasters crazy!  🙂   Just reading their long-range week 2 to 4 discussions are Entertaining to say the least!  They keep trying to force a pattern that does not want to be.  This is a transition from season to season that has got to be so frustrating for the experts!

The teleconnections keep changing all the time!  The European shows an -EPO developing toward the end of the month and the new 12z deterministic  GFS today shows a -WPO and cutoff high in the Bering Sea with a break through of the westerlies underneath.  This obviously sets up two different patterns!  Will update later….enjoy the great snow in the upper elevations…..:-)

 

The Dweeber……………….:-)

 

Moderate to Strong AR to effect the Central Sierra Wednesday night and Thursday with heavy snowfall expected over the higher elevations…..Weekend looks to be Dry…

WEDNESDAY PM UPDATE:

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.

Outlook:

 

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….:-{

 

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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.

Outlook:

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……………………:-)