Cold Winter Like Weather to bring snowshowers over Mammoth Mt today along with Mid Winter Temperatures…..After a break early next week another wetter storm moves in Friday……

Tuesday AM the 10th:

Beautiful morning with Mammoth snow covered.  Cold with morning lows in the single digits and teens.

Weather pattern this morning shows NW flow with short wave bringing high clouds to our area. Precip in Pacific NW with sheering trof and energy forecasted mainly east over the Northern Rockies.  A warm air advection pattern follows with gradually rising snow levels over the weekend. This next system to effect the Mammoth area is expected to bring mainly light amounts of snowfall, up to 4 tenth of an inch H20 EQ currently forecasted. So a few inches possible.  It may begin as snow in town but turn to rain later in the weekend at elevations below 8K.   Warm air advection pattern can be trickier with snowfall est.  Models do not do as well as dynamically induced precip.  Feel comfortable in the 3 to 6 inch range between Friday and Sunday at this time over the Crest.  Much less in town with rain/snow mix at the end. Next WX system Tuesday or Wednesday next week.

 

Longer Range:

Based upon NCEP’s tropical discussion today,  the MJO weakened as it moved over the colder waters of La Ninia. It will enhance upper divergence over the far Eastern Pacific and Caribbean this week, before it emerges over the Indian Ocean.   As it moves over the warm waters of the Indian Ocean, expect strengthening. With strengthening, comes a signal for the mid latitudes. This is expected to set up -PNA (Trof over the far west) and Ridge in the east, further delaying Winter for the east with a stormy period out west. This is expected later week 2, (2nd half of next week), through the following week)   (so about the 20th through the 29th).

Expect odds for moisture leaden storms to increase for the west coast later week 2 through most of the remainder of November.

More Later……

Dr Howard and the Dweebs………………..:-)

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Of note, it has been below freezing in Mammoth for the last 24 hours.  Snowfall will wind-down today with possibly a few more inches to add to the 12 inches that has accumulated at the Main Lodge the past 36 hours.  The air is clean and fresh!  Just the way we like it!   The Cold Low is currently sliding SSW and will back door us today.  Dynamically, the main focus will be the Southern Sierra south to Southern CA for precipitation today….Highs today will be in the mid 20s with a bone chilling 4 degrees expected by Monday Morning.   Currently, Snowfall amounts on Mammoth Mt are within forecast, (10 to 15) inches. A few more inches may fall mainly this AM with just some light snowshowers the remainder of the day.

The Storm, (Pattern Wise) that brought snowfall to our region is classic in a La Nina Winter.   Cold Great Basin Long Wave trof with energy entering CA from a short distance off the west coast. This pattern is cold with usually light to moderate snowfall with any individual storm (Short Wave)……

Outlook:

The next weather system appears to have an small AR connected to it….That would be next Friday.

WX Pattern:

The Pattern later next week as shown in the 5 day means, 500mb heights, shifts the current long wave now over the Great Basin and Inter mountain westward, well off shore.  The upper jet relative to CA has currently little over water trajectory, however, is strong dynamically with lots of cold air aloft.

Again…The day 5 means shows the long wave trough retrograding over the next 5 to 7 days.  There is deamplifacation in the process where-by an almost zonal upper jet develops with lots of over water trajectory from the North Pacific to the Northern and Central CA Coast.  The longwave shifts westward to around 125 to 130 west. The upper jet also lifts northward up into the Pacific NW.

There has been an atmospheric river of modest intensity shown in the models the past few days for next Friday. The storm and pattern later next week is one of mainly warm air advection, whereby moisture coming in from the pacific is being lifted over the existing cold surface, like what we have at the moment over California. There is not much in the way of any dynamics  (vertical motion)  from a pattern like this. However, the forecasted winds at 700MB along with significant moisture advection can produce a fair amount of precipitation, well south of the anticipated upper jet position.  Snow levels will undoubtedly rise….Possibly up to 8,000 or 9000 feet.

This is what we need at this time of the year, good old fashion Sierra Cement, not cold dry powder, like what we just received!

I see more storms later in the month…..November looks Marvelous and setting up December for the holidays…………….

Dr Howard and the Dweebs……………….:-)

Another 3 to 4 days of Mild Weather then Major Pattern change this weekend to one of which is much colder with…….Snowfall……30 degree drop in temperatures expected by Sunday…..

10:00AM Wednesday the 4th of November….

Not much change to the forecast other than the Sunday system may be a little colder.   System one is slowing a bit which is a good point. Most of the precip will be behind the front.  CRFC is painting between 4 and 5 tenths between Huntington Lake and Yosemite.  That’s good for at least 5 inches of snowfall over the crest from storm one. Storm 2 is more of an inside slider type and so the crest usually does better than the west side.   All in all we may end of with around 12 to 15 inches on top of the Mountain by Sunday night.   However…theres still time to adjust.  Remember, the 2nd system is colder and snow to water ratio’s will be higher Sunday and Sunday night.   It will really be cold too with highs in the 20s on Sunday!! Lows in the single digits.   More unsettled weather next week!

Dr Howard and trhe Dweebs……………………………:-)

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Although the details have yet to be ironed our as far as snowfall amounts on Mammoth Mt,  it does appear that at least light amounts of snowfall will occur this weekend and there could be more.  Light amounts (1-6) inches. Moderate  (6 to 18 inches)

  1. The Major PNA teleconnection goes negative for at least a week, meaning that a Trof in the mean is expected to set up over the inter mountain west, over the 6 to 10 day period. This pattern is highlighted by much colder than normal temperatures and light to possibly moderate snowfall. The key will be how much upper jet gets off the coast this weekend. At the moment, the first system is expected to be a fast mover and so only light amounts are expected. However, the second system is slower and colder.  It could very well end up being a good snow producer for the sierra. Again, these storms are going to be quite cold with the 2nd system capable of producing snow to water ratios of 15 to 1, over the higher elevations Sunday.

Model Differences;

  1. Where we are at the moment is that this mornings GFS jogged a bit east with its initial short wave and was quite fast on moving it through. That’s a drier scenario.  The Euro seems to be more consistent with plenty of off shore upper jet support.  As for-mentioned, the 2nd system for Sunday seems more interesting today.

Pattern Change and Teleconnection;

  1. Change in the PNA teleconnection to negative through mid month, suggests that these weekend storms are not likely to be the last and that more snowfall is possible that following week.   Again, it is too soon to take a guess at how much we may get….  Better visibility on that subject by this Wednesday.

Dr Howard and the Dweebs………..:-)

Beautiful Sunny Mild Days and chilly nights on tap through the Weekend…..Forecast models continue to hang on to the ENE flow a bit longer…..So Smoke to remain west for another day….MJO on the Move…..

10:40AM Saturday; All Hallows Eve

Mother Nature is giving us a nice day today as winds at 10,000ft (500MB) increased out of the ENE to 25MPH after 5:00AM this morning. Those ENE winds will continue today. This will give us a steller day with clear skys and warm temps by early afternoon. Winds will continue from the the east Sunday but will be much lighter and may give way to more terrain driven breezes. This may allow some haze to move back into the Mammoth area.  These are very subtle changes and may or may not allow any haze to return. By Monday and Tuesday, the upper high as depected by this mornings GFS is centered over the top of us. However, it is a flat ridge that will give way to increasing westerly flow by Friday.  Can’t rule out some haze next week depending upon the fires behavor.   As far as temperatures are concerned, sensibly, there is not expected to be any notable changes expected through Thursday, with highs in Mammoth in the low to mid 60s and lows at night in the 25 to 30 degree range. It is a dry 4 to 6 day outlook.

Windy weather will develop Friday morning as a vigorious cold front approaches. The Dweebs expect mainly light precipitation from this system Friday afternoon into Saturday with strong winds and colder temperatures. This is not expected to be a major precip producer, however, with another system Sunday, amounts may add up. More later on this….

MJO:

The Madden Julian Oscillation is expected to weaken substantually as it moves over the colder waters of the LA Nina Base state next week. So although it does proppagate through the Western Hemisphere, then out over the Indian Ocean, it is very questionable how strong the pattern change for the weekend will be as the MJO will lend little support.  More time is needed to see how it all develops. and how much snow we will get.  One thing is for sure, its convective envelope is likley to light up the Caribbean again and so Huirracane Zeta that hit New Orleans Wednesday, is not likley to be the last Hurracanne to affect The Caribbean in November!

 

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

 

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4:30PM

Looking out at Mammoth Mountain late this afternoon. it is evident that something is going on over the higher flight levels. That is smoke folks. However it is at Flight levels of 250MB or about 36,000 feet.   Looking at the 250mb flight level charts, the winds are south westerly…While the winds at 700mb (10,000 ft) are East North Easterly. That is why we continue to be smoke free!  Tomorrows winds at 700MB are forecasted to really lighten up during the day. So do not be surprised when the smoke or haze rolls in again.  Sorry for the news, but we have had some great air quality. However, most likely, it will worsen during the day Friday.

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This mornings models runs seem to keep enough ENE flow at 700mb to keep the majority of the smoke to the west of the Crest today and “Possibly Friday” Now…..There seems to be variable periods of NE flow into Sunday. In between are the diurnal terrain driven breezes that can creep the smoke back over the crest into Mammoth.  So it may be that if we do get some haze or smoke,  it may not be a major problem, or like all the time over the weekend….Forecast indices light winds the next 7 days with above normal temps. Highs in Mammoth will be in the mid to upper 60s with lows between 33 and 25 degrees. The colder temps will be over the lowest elevations of town, just below the inversion.

MJO:

  1. Equatorial Rossby wave activity over the West Pacific, and increasing destructive interference with the La Niña base state may be playing a role in the slower evolution of the signal.
  2. Despite the recent slowdown of the intra-seasonal signal,  dynamical models continue to favor robust propagation of the MJO across the Pacific over the next two weeks. The GEFS brings the index to the Western Hemisphere by Week-2.
  3. Due to the ongoing destructive interference, confidence in robust MJO activity over the next two weeks is low; however, should the signal reach the Western Hemisphere, it could help bring about a pattern change from our currently dry pattern to at least some precipitation for California, between the 6th of November and the 12th. The GFS and ECMWF are just picking up on the pattern change for the week 2 period. However, with that said, there is no significant confidence at this time. The MJO will have to make it through the Central Pacific, in this case, the (DEAD ZONE) 160 East then hold together strong enough to modulate the Westerlies. Its forecast remains a moderate Phase 8 into 1, In Early to Mid-November.  There is a decent signal for precipitation in phase 8/1 (undercutting of the westerlies)  In January, this phase when strong can bring us those magnificent Pineapple Expresses. However, phases 2 and 3 (Indian Ocean) are by far the best phases to be in For Central CA this time of the year.  This is probably 3 weeks away.  See the teleconnections for the MJO precip to phase in November.
  4. SEE: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/Composites/Precipitation/

The Dweeber…….:-)