Cold Upper Low to slowly head south the next few days….Eventually bringing Mod to Hvy Snowfall to the Eastern Sierra Sunday/Ngt…..After a small break by Thursday and Friday…. Another system affects the west coast by weeks end…..A series of storms look to bring more snowfall to the Sierra through months end….

5:30pm  Sunday

This storm is certainty the creeper. Although yesterdays forecast below indicated that the front would be near Mammoth at 00z Monday. (Sunday at 5:00PM),  the updated forecast shows it will not come through until about 11:00AM Monday.  So do not expect snowfall to become heavy until well after midnight tonight…Heaviest snowfall will probably be Mid Morning Monday…. Expect good snowfall Monday into Tuesday…

 

Although currently closed now, Mammoth Mt reported 7 to 10 inches of snow today Sunday.

 

Dr Howard and the Dweebs……………………:-)

 

______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

This Afternoon’s Analysis had a cold Low off the Oregon coast with a front pretty much stationary over Northern CA. Heavy precip was falling over Northern CA with strong winds buffeting the Eastern Sierra. Light orographical precip was being lifted over the Sierra in the strong SW flow.  As the upper low drops south Sunday from Northern CA, snowfall will pick up with a FROPA expected by late afternoon or early evening Sunday for Southern Mono County. Strong Vertical motion fields are indicated Sunday night into Early Monday AM.  In that the Closed Low continues south and becomes a bit cut off….it is difficult to know where the features will come east through Southern CA. Most models take it east through About San Diego but the EC had it coming east further north.  These considerations would determine the possibility of up-slope for the Eastern Sierra, Tuesday or Wednesday….

 

The highlights of this storm for the Sierra Are;

1. The front is progged to stall near Tahoe for some 18 to 20 hours giving them the big dump….”today into Sunday AM”. By Sunday at 500PM the front is near Mammoth Lakes.   So our heaviest snowfall will be Sunday afternoon through Early Monday AM. At some point the upper flow becomes southerly and that cuts off the orographics…. But by When???  And as mentioned earlier, will the Eastern Sierra get into a good up-slope pattern Tuesday? All these things determan how much snowfall we will get in Southern Mono County. 2 to 3 feet by mid week not unreasonable thinking….

 

Stay Tuned…………….:-)

Mammoth Mt adds 2 inches to its base with another light snowfall expected for Monday – Wednesday…Main focus of next storm targets Southern CA, with best precipitation expectations……Change in Pattern comes later next week as short wave energy returns, closer to the west coast with moderate snowfall potential and colder than normal temperatures….

3-10-20

9:00AM

Just to be brief….Although areas of Heavy Rain are expected to develop in the southern portions of the Owens Valley late today and this evening, Expectations is that this continues to be a light snowfall producing system for the Mono County High Country, with 1 to 4 inches expected above 7000 to 8000 feet.

Of more interest, is a pattern change now developing over the Gulf of AK (-EPO) with a strengthening positive upper height anomaly (High Pressure aloft at 18000 ft) providing high latitude blocking in that area. There does not appear to be any undercutting forecasted by the models. However, the screaming message this morning is that all 5 global models that I have seen, including the outlier GFS from yesterday, now have the upper center forming off, or just off the coast of Northern CA over the weekend as it tracks SSE.. The system may slow down as well. At the same time, the upper flow becomes natural to the Sierra, thus there should be good orographical enhancement with this weather system. Considering the storm motion….Potentially moderate to even heavy snowfall, of the likes we have not seen since last December may develop, beginning Saturday then into Tuesday. So far the Northern Sierra is targeted for the Bulls-Eye with greatest snowfall potential in their high country.

 

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

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

12:25 PM 3/9 Update:

 

Latest model runs show the Ecmwf  having a good snow producer for the Central Sierra Later Saturday into early the following week.   However the GFS has more of an inland track which severely limits the snowfall. This model solution give us all the cold and wind, but not much more than light amounts.  The Canadian Model is more like the ECMWF but quicker getting into Mammoth on Saturday and slower to leave on Monday. Looking at the 12z UK, its trof axis is on the coast and the JAMSTICK has over water trajectory as well. So the message this afternoon is that the vast majority of the models give us a good snow storm later Saturday into Monday AM.   The GFS is currently the outlier, but its Ensembles are more optimistic….

 

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Our forecast models continue their trend of over forecasting snowfall amounts at distance, then back peddling within 3 days before an event.  For our particular area, as evidenced by the 2 inches received yesterday.  What appeared potentially to be more of a moderate snowfall producer for Mammoth Mt for the first half of this new week, now has been down graded to one of light exceptions…..1 to 6 inches.  So far, nothing appears in our two week outlook that resembles anything like a Miracle March. However, looking down the road, there are still some interesting possibilities worth considering beginning next weekend and the following week.

 

The Low pressure system that was due west of the Bay Area area this morning and may I add well off shore, is headed for Southern CA, where it will in counter a rich source of PWAT. This gets en-trained into the system and is expected to bring moderate with isolated areas of heavy rains to LA, between Monday and Wednesday. This storm stalls some-what during the day Wednesday before heading down the coast, thus not the more eastward through LA track like earlier progged.  This southward jog, will have the affect of limiting both the upper divergence, then upslope over our area during the Monday through Wednesday. However, the Owens Valley still looks to do well, especially the southern portion. This is a prime example of why forecasters are leery about precip forecasts 5 days out when you have a closed or cut off low, as higher than normal inaccuracies will exist in the storms track.

Later in the week, the models are converging on a solution of a storm track down the west coast again, similar to what we have had most of the winter. The last storm that dropped a foot on Mammoth Mt a week ago, was from a similar storm track.  However, the trof remained open long enough to get good upper flow through the Sierra. Will this trough remain open or will it wind up and head down the coast?  Only time will tell by the end of this new week. Beginning next weekend, the week two models are converging on a -EPO teleconnection of very strong negative proportions. a -5 to -6 DN.   So this means that very strong blocking will be developing in the Gulf of Alaska around mid month.  The AO Arctic Oscillation will be positive and so the Arctic looks to remain locked up, much like it has been all winter, but the PNA goes very negative.  So what does this all mean? The -PNA argues for colder than normal temps returning to the west and high country. The blocking may have two distant possibilities, one of undercutting of a branch of the westerlies and two, a track over the AK high and down the west coast.  So this is where the models will try to resolve there equations, in time and space…..Lots of possibilities and with any luck of the Irish, we may get a good storm…..;-)

 

Dr Howard and the Dweebs……………………….:-)

 

 

 

Cooler weather expected by the weekend with some light snowfall possible……Series of Closed Lows to slowly take aim on California next week…..Periods of moderate precipitation possible….

3-6-20

TGIF

Focus now  will be the big rain maker getting set up for Southern CA.  There is a rich source tropical plume just north of the dateline associated with the low frequency base state that has connection east, then North Eastward to Northern Baja and Southern CA. next week.   A short wave, in back of the wave that will bring Mammoth some light snowfall Saturday, is currently moving ESE through the G of AK and will drop south and spin up over the next several days as it makes its way toward Southern CA early next week. The Closed nature of the system makes it more difficult to time as compared to the open wave across the pacific.  Our friend the EC ensembles puts it through Southern CA next Wednesday.  As a result, the best forcing will be Monday and Tuesday as a rich tap of tropical moisture combines with both dynamic lift as well as Orographics.  The coastal sections of So-Cal seem to have the best combo, especially areas like Malibu, east and south. This should be a good rain maker from Southern CA east…..

Mammoth Mt;

 

Preliminary est….2 to 5 inches over the crest Saturday. and another 12 to 15 inches Monday-Wednesday.  Dry Thursday.  Highs today fFriday in the low 50s cooling to the 40s on Saturday and low 40s Sunday. Expect 40s for high in town early next week.  This is not considered a cold storm. Snow level will rise to around 6000-6500 feet. It will be breezy this afternoon through Saturday night. Windy over the crest….

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Currently, Mammoth Lakes is under high pressure ridging, We can expect above normal high temperatures through Friday with low to mid 50s. There after, a “long wave trof” will set up over the Eastern Pacific allowing slow moving closed lows to creep on shore. The period Monday through Wednesday next week could bring fresh snowfall to Mammoth Mt. Although the exact trajectory of this system is Unknown at this time. The effects of the next lifting mechanism to boot it in will determine who gets the lion share.  There is the potential of moderate snowfall on Mammoth Mt next week. Moderate  (6-18 inches)  The long range outlooks from both the CFC and CPC show the potential for a wetter March, especially for Southern CA. The CPC has indicated that an area of enhanced convection over the tropics near the Dateline may supply atmospheric river moisture in the weeks to come for Southern CA.

 

CPC: