Two more weather Systems to affect our area through Mid Week….Light to Moderate snowfall possible…..EPO to go positive in April….

3-23-2020 6:45PM

 

Although Mammoth Mt is closed, they reported 4 to 6 inches of snow from the Sunday afternoon/night system. The last in the series will be moving in Tuesday, bringing more wind and snowfall into early Thursday AM   This would be considered a low end moderate storm. The main upper low is more over land now than off shore. However, there is still plenty of upper jet coming in from off shore to give us good west-side up-slope, and possibly 6 to 12 inches over the upper elevations and along the crest. The snow will be cold and powdery by Wednesday.  In town, light amounts are expected with between 3 and 6 inches between Tuesday and Thursday.  This looks to be the last in the series of weather systems to affect our area.  In reference to the discussion below, the Eastern Pacific Oscillation is going positive with lower pressure in the Gulf of Alaska for the first week of April. That usually allows for 500mb height rises along the west coast, and a northward retreated upper jet.  It will be colder that normal through Friday with high temps cooling to the upper 20s by mid week and lows in the teens….

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Chilly Weather with below normal temps are expected to continue through mid week.  High temps will be mostly in the 30s with lows in the teens and twenties.

There are two weather systems that will bring more snowfall to Mammoth.  The one Sunday night/Monday AM is a weakening system that will being light snowfall to town…..Between 2 to 4 inches.  The system Tuesday and Wednesday could bring another 4 to 7 inches in town by Thursday AM. Will Update amounts for the mid week storm on Monday.

The last in the series of storms is expected to bring quite a bit of wind Monday Night through Tuesday Night  Teleconnections show that the -EPO will be going positive. That is usually accompanied by the Polar Jet retreating to our north again. Temperatures are likely to return to near normal during week 2.

The following weekend looks cool with a NW flow aloft. There is a small wave coming through late Saturday that may bring some snow showers.  We’ll see…..

Otherwise, although the GFS has more storminess the following week….The Eastern Pacific Oscillation goes positive.  That means that it will be more difficult for storms to get in here…..But not impossible….

 

Stay Safe…..Stay Healthy…..Listen to your officials….

 

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

 

 

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……………………:-)

 

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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……………………………:-)

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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….

 

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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……………………….:-)