Current storm system continues to dump snow on Mammoth Mt Saturday, while next AR takes aim on the High Country Tuesday…..Several low pressure systems expected to migrate through our area Wednesday through Friday…..Colder air on the way for Friday…….MJO starting to be affected by ENSO….Diving into the circle of death…..

Wednesday 9:40AM

The snow plot at 9000 Feet showed about 3 inches of water and at the ambient temperatures at the summit in the mid 20s

that would translate to at least 2.5 feet of new snow at the summit. Another 2.5+ inches is expected through mid day Friday and so we may hit that 5 foot mark of new snow yet at the summit.  Officially at this time, up to 17 inches of snow has fallen at the main lodge.

Our AR has shifted south into Southern CA. cooler temps are on the way for Mammoth.  The latest model simulations show the present trof shifting south today through Thursday with more showery weather expected Thursday. A NW slider will keep the snow showers going Friday AM.    The next upstream system for Saturday seems to want to remain off shore far enough to keep most of the precipitation west of us. Although the upper jet is over Central CA Saturday, the vertical motion field is too far west. That is progged to change late Saturday night and Sunday as the system both nears the coast and shifts south down the coast……Precipitation chances should increase again in our area.

 

The Dweeber

 

 

 

 

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Monday AM

No changes this morning….mid latitude low and associated AR, are forecasted to begin bringing rain and snow to the region Tuesday. The snow level Tuesday my go up to as high as 8000 Tuesday morning, before coming down to between 7000 and 7500 Tuesday afternoon.   Winter storm watches are in place beginning 10:00AM Tuesday by the NWS. 1 to 3 feet is expected above 7000 feet by Wednesday night. The Dweebs believe another foot or two expected by Friday.  Models are changing their tune for the weekend. It may not be all that sunny, with another storm possible. With MJO diving into the circle of death and El Niño now coupling to  Larger scale planetary flow, will westerlies react according.

Sunday AM. 1050AM

Only changes to the Tuesday AR is that the polar and subtropical jets are only partially coupled. However, I am not concerned about the heaviest amounts for our area as the hose is pointed NE through the Inyo-Mono county boarder Tuesday. I think that unless there is enough vertical motion which is looking more unlikely Tuesday, it will be mostly rain or snow-rain mix for the Town of Mammoth until Tuesday night when the freezing levels drop.

Up on Mammoth Mt, it will be all snow at the main lodge and above with good base building SIERRA cement Tuesday and Tuesday night. This storm along with other colder systems next week should bring and additional 5 to 6 feet over the upper elevations by the following weekend. The longer range is showing signs of the winter machine getting tired.  The MJO goes into the circle of death. Whether or not this happens is another story for a later time as the low frequency base state of El Niño may be getting ready to exert more influence upon tropical forcing…Remember this El Niño is a Modoki and may bring a dryer pattern to CA in the not too distant future. Some of the ENSO models predict El Niño to strengthen over the Summer. I would be cautious buying into all that as the Spring Barrier is not all that far off.

 

The Dweeber………………..:-)

 

 

 

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The vertical motion in the current storm is rapidly increasing as the main Vort max is expected through our area by 03Z.   Lots of yellow lighting up the radar near Fresno at 2:00 PM…Thus it is becoming prime time for this storm. The current heavy snowfall will be tapering off to showers after 6 or 7 PM. Mammoth Mt reported up to 12 inches for overnight amounts in their morning update.  Up to another 12 inches is expected by this evening…. Storm total should be in the 12 to 24 inch range. Heavy wet snow was falling in the Town of Mammoth Saturday afternoon..

There will be a break in the action Sunday into Monday with only snow showers expected Sunday….It will be dry and a good travel day Monday.

The next series of storms will begin this Tuesday. There is an AR attached to it with the AR pointed just north of Point Conception.  The upper low coming in will draw up that subtropical moisture and point most of it into the Southern and Central Sierra. Mammoth appears to be right on the border of the richest portion of the AR, benefiting well from the AR. For the day Tuesday, there is little Vertical Motion indicated and so do not look for heaviest amounts on the east side. Amounts on the West Side will be heaviest because of the orographics. The Snow to Water ratios will be low on Tuesday as the AR moves in, with the freezing level as high as 8000 feet on Tuesday. It may be rain snow mix in town.  The Freezing level will begin to come down late in the day on Tuesday and into Wednesday. As the vertical motion field really cranks up Wednesday mid morning…  The Town of Mammoth should have its heaviest accumulation of snows late Wednesday AM and into Thursday as several low pressure impulses systems spin up into the high country. Although the AR will be pushing south by Wednesday,  the vertical motion increases for Mammoth and will deliver increasingly heavier amounts of snowfall beginning mid to late morning Wednesday as the colder air moves in as well. Heavy accumulations are expected in town late morning through Wednesday night. The vertical motion field stays strong through Thursday night.

Upper Jet;

Saturdays 18Z run of the gfs shows the polar upper jet over Northern CA within the Subtropical Ridge and both the polar and STJ coupled well off shore. This is supporting the AR as it comes into Southern CA. Over the following hours, the coupled polar jet drops south quickly Wednesday morning while still coupled.  WOW!!  The AR moisture gets sucked up over the Southern and Central Sierra Wednesday for a real Snow Day!! This continues through Wednesday night and into Thursday as the coupling continues into Thursday!  The freezing level goes from about 8000 feet mid day Tuesday to 7000 feet mid-day Wednesday to 6200 mid-day Thursday to 4200 feet Friday AM. By 4:00AM Friday, the upper low will be just to the south of us and so as of this time, it looks snow showery Friday and dry Saturday.  Looks like between 2 to 3 feet in town and some 3 to 5 feet on Ol’ woolly by Friday.

The next storm in the longest range for whatever it is worth,  looks to be the following Wednesday the 13th.

 

MJO;

The RMM phase space for the MJO shows it is currently in Phase Space 2 and into phase 3 over the next few days….These are all wet phases for Mammoth. However, the GFS has the MJO retrograding back to phase one and very weak by . The CFS has it back to 8-1 and week. Might this finally be the EL Nino coupling that we have been waiting for? More later on this, this Tuesday or Wednesday. By around the 15th the MJO looks pretty weak.

 

Dr Howard and the Dweebs………………………:-)

 

 

Main Upper Jet continues to be aimed at Northern CA with its Moderate AR….Snow for Mammoth to begin late very tonight into Thursday…..Unsettled weather likely this weekend and next week…

2/27/2019. 5:00am

The AR has weakened and moved south into Mono County this morning and light to moderate snow fall can be expected through Thursday. Amounts above 7500 feet including the town will vary between 4 and 12 inches by Thursday afternoon.  There will be a break Friday with a small storm Saturday.  There appears to be a bigger system in the eastern pacific with a sizable AR will affect Mono County next Tuesday and Wednesday. With the AK block breaking down and a higher amplified upstream ridge taking shape, The pattern begins to favor areas more to the south again as the next week progresses.

At this time, the longer range shows no let up in the series of storms for the month of March….

 

the Dweeber……..

 

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Hello Fellow Dweebs!..   I have been asked several times about the Snow Phone and why it has not been working since the end of last month.   Well, it got lost in my move at the end of January, meaning that the phone company was not been able to get the phone line set up mostly due to the weather. That changed today. Hopefully, the weather phone will be in operation this weekend.

Mammoth sure has had an interesting winter so far.  There are actually two full days left of Meteorological winter as March first is the first day of meteorological Spring. This is different than the astronomical seasons by the calendar. The differences in this case, lie more in the behavior of climate in March than the three month previous.

The Past Week;

The forecast has worked out well.  It was indicated that a pattern change would be initiated by the Madden Julian Oscillation some 10 days ago as it was forecasted to move from phase 7 to 8 then cross into Phase 1, (East of the Date line). The tropical convection of the MJO continues strong. In my opinion, it initiated the (-EPO) and that was the cause of the change.  This change happened last weekend and here we are with a Closed Blocking high over Alaska, a strong trof over Eastern Russia and the EAJ forcing itself upon the block, splitting short wave energy under the block in the form of a negative height anomaly between the GOA and NE of Hawaii. The persistent upper low off the coast of the pacific northwest is phased with the flow coming northeast north of Hawaii. This is your moderate AR into Northern CA. Although the bulk of the energy as far as precip is focused from the Bay Area NE to Tahoe as expected, the winds have been horrendous. The cold air left in place from last weeks cold wave initially added to the gradient, then combined with over running warm air advection creating a downslope signature along the Lee of the Sierra Front. Most of the serious winds have been between June Lake along Highway 395 north to Reno. Gusts to about 100 miles per hours toppled several 18 wheelers along the highway Monday afternoon. The Down Slope signature is still there so be careful when traveling. Not only do to the Winds create problems for high profile travelers, but due to ground blizzard conditions, visibility can be reduced to zero at times as well.

Looking Forward:

The AR is shifting south and weakening. Best snowfall for the high country will be Wednesday morning into Thursday with amounts in the Town of Mammoth at the 8000 foot level between 10 and 20 inches and over the upper elevations about 20 to 30 inches between midnight Tuesday night and Thursday evening.  There will be a break Friday with the next system coming in Saturday into Sunday.  The models have been steadily weakening this storm and on the 18Z GFS dampening it out. There is not a lot of confidence in how much snowfall we will get but as time goes by it is looking less and less. Best guess get 4 to 6 inches in town and some 6 to 12 inches on the mountain.  I will update on amounts again on the weekend storm Thursday. I am sure amounts will change.

 

Longer Range:

The MJO is on the move, quickly going from Phases 1 to 3.  According to the MJO composites for March, these are still wet phases for Mammoth.  The pattern seems to become more progressive later next week with the break down of the block. It still looks like we will have the chance for another strong storm about mid week.  For what it is worth, both the 6 to 10 day and 8 to 14 day outlooks from the CPC are wet for Central CA.   In that the pattern goes into transition again next week, I will hold off on any serious outlook until later this week.

 

Dr Howard and the Dweebs……………………:-)

 

 

 

 

Cold weather to remain this week with light snowfall Wednesday night and Thursday……Pattern Transition likely next week….

Thursday AM the 21st…

looking at the 00z ecmwf and gfs…they come to agreement at this time of bringing the bulk of the precipitation with the initial AR to Northern California with the biggest push of precipitation for Mammoth beginning about March 1st through that 1st weekend of March. There after, there will be a series of storms affecting the central sierra as the upper jet favors our area again. Theses systems are likely to have subtropical connections as well.

In that the upper jet will be up in Oregon early next week, the best forcing will be closer to the jet.  Copious amounts of rain and snow seems destined for the northern part of our state beginning early next week with lighter amounts for the Central Sierra. The central and the northern part of the Southern Sierra is likely to benefit better about the 1st or 2nd of March with another possibly stronger forcing period early the following week.  So….The first good opportunity for Dynamic forcing will be about week away  A second storm after the March 2nd storm at this time looked even stronger as it is further south. There are another two systems possible afterwords…..  More later…..

 

will check on the longer range QPF after the weekend….

 

The dweeber……..

 

 

Wednesday night;

The second storm dropping south on Sunday will stall out some where north of highway 80 to the Oregon border with polar jet being confined to OR/CA border early next week. The polar jet is also parallel to the upper flow so this looks to be a stationary boundary. This area of bounty sets up with mild moist pacific air mass flowing in, under the polar jet. It appears that there is some confluence of the flow at 500mb between the mid pacific air and the polar jet just a few hundred miles off the Northern CA coast Monday. It also appears that either the right rear entrance region of the polar jet and or possibly a weak extension of the subtropical jet will become active next week as well.

So initially, the best forcing looks to be over Northern CA early next week. However, this mid pacific moisture can produce light over running snowfall here, as there is plenty of cold air around the central sierra.

The GFS also has a modest AR moisture tap that begins over Northern Ca Monday and slides south to the Central  Sierra Tuesday into Wednesday. So the likelihood of precipitation is increasing with snowfall a possibility as early as Sunday or Monday, however better chances toward mid-week. At the moment, although the first AR has a moderate Moisture tap, it does not look like a major storm as there is little vertical motion.

It should be noted that AR moisture usually needs strong vertical motion for it to become a heavy precipitation producer. At this time those features may come later in the week like the following weekend with the possibility of a stronger looking AR in tonight’s 00z GFS.

By this Monday, there should be plenty of ensemble members for a much better idea what kind of animal we are looking at next week.

The tempo is picking up…….⛷🏂

 

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Wednesday the 20th

The prospects for another AR as touted in several posts prior to this one are increasing now as last nights 12z Euro has come in step with the GFS idea of a strong eastern pacific oscillation in the negative phase. (-EPO)

The global models have followed the MJOs movement from phase 8 which it is into now, to phase 1, which moves it to the east of the dateline. This transition often, but not always creates, 1. Fast meridional flow (n/s) with the results of building a big blocking high over Alaska, followed by the undercutting of the westerlies. The trick for the forecasters in this case is to determine which global solution is the correct one at distance, between the euro model which is deeper with the newly formed eastern trof or the shallower gfs solution. The shallower trof is more progressive and moves quicker to the east and thus opens the AR door quicker to the west coast.

Timing between the models is at the soonest….about a week away, to as late in the ecmwfs case the end of that weekend.

This pattern has the potential to be a major event for CA…..

As always…..patterns can change….So the Dweebs will keep you all in the loop…..

 

Dr Howard and the Dweebs…….

 

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The month of March often has two faces for the forecaster as the first half of the month is more like winter while the second half is more like spring. The second half of that month is much less reliable for longer range forecasting so the Dweebs will take note accordingly….

After an exceptionally cold February, there appears to be relief on the way for next week. However, This week will still be exceptionally cold as the persistent western trof dominates through this work week. The latest GFS 12z run along with its ensembles still shows a -EPO set up by the next Wednesday. This is highlighted by strong positive height anomaly over the state of Alaska. The westerlies naturally under cut this block this time of the year.

The differences between the EURO and the GFS are seen week two as both models move the western trof east.  However, the euro has a much deeper eastern trof and further south. This models solution would cause stronger height rises along the west coast while the GFS is more shallow and east west with its eastern trof and more progressive. Both models have a belt of westerlies under cutting the AK high, however, the GFS is faster moving it into the west coast while the EC solution is slower because of the deeper eastern trof solution.

Additionally, the GFS has the MJO in phase 8 Longer than the  EC.  The storms off the west coast early next month are likely to have an AR connected to them and so they will be good Percip producers when they come in, sometime during the first week of March.

In the meantime expect the cold weather to continue this week with temperatures becoming much milder as we get into and progress through the following week.

snowfall tally’s from the Wed/Thur storm will be 1 to 3 inches in town and 3 to 6 on the Mt.