Blustery Northwest Jet will keep weather unsettled this week with cool windy showery weather…….Warm-up expected by the end of the weekend….Longer range shows a nice warm period beginning the first week of May….

For the Dweebs, this is my least favorite time of the year.  It is the transition season between Spring and Summer with the northwest jet prolonged through Northern and Central CA. The Jet is tilted NW/SE as a long wave upper high inside of 140 west is too far off shore to bring warm temperatures and too close to California for any major storms. The front right exit region favors the sierra with “Wave Clouds”, so you wave cloud photographers, will have the opportunity for some good shots this week in the early AM hours and late afternoon mostly areas east of Highway 395.  The NW jet with its front right exit region over the central sierra favors convergence aloft in this sector. Downward vertical motion results in strong winds at times aloft and mainly orographically induced snow showers. 

It will be quite breezy to windy over the upper elevations on Mammoth Mt most of this work week.

There will be nuisance snow showers this week, mainly Monday through Wednesday morning. However, the showers will not add up to much of anything.  I call it nuisance weather!  But it is necessary to get the season along before summer finally hits in June.  Expect highs in the 40s and low 50s with lows in the 20s and 30s.  Winds will Crank at times to 80MPH over the crest with gusty winds in town as well.

Will there be one last storm before summer hits?

Maybe more than one….

I just had a peak at the European Ensembles for week two. (next week) It shows; 1st,  The sharpening of the upper ridge off shore without the progression of it into California. This argues against any big lasting warmup. It shows a cold low dropping SW from Alberta Canada on the 1st and settling in over the Western Great Basin on the May 2nd.  There after, retrogression takes place with the next short wave dropping south down the west coast. Meanwhile, the upstream ridge retrogrades west and builds up into Alaska, (-EPO) style.

So here we go again!!  Remember, this is the Euro, not the GFS.

 

The Climate Models CFS climate forecast system suggest that the 3rd week of May will be colder than normal with the chance of snowfall.  No telling how much though.

 

 


Atmospheric River in process ending Tuesday afternoon by 5:00PM….Then on and off showery weather into Thursday followed by a very warm fair weekend…..

4/19/2017 Update:

 

Our Atmospheric River shifted south late yesterday, leaving 2.17 inches of water in the Rain/Snow melt tip bucket this morning. Mammoth Pass picked up another 4.00+ inches of water and Mammoth Mt reports a storm total of 18 to 26 inches of fresh snowfall.  A big story this morning is that Mammoth Mt crossed the 600 inch mark for snowfall for the season with 605 inches.   However, the bigger story is the amount of snow and water that has fallen out of the skies over the past 6 to 7 months. That is 98.57 inches of water. This is most likely a record.  Crossing the 100 inch threshold is going to be the biggest news when it happens!   Sure a 600 inch snowfall winter is note worthy, but a 100 inches of water from both snow and rain is nothing short of amazing!

I am expecting a few showers tonight followed by a beautiful sunny warm weekend!   It will be windy next week with a slight chance of showers…..

 

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

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The Great winter of 2017 continues to wind down. The upcoming week shows the likelihood of light to possibly moderate precipitation at times through Thursday. There is a weak to moderate AR in process. This is acting to keep the snow level closer to the freezing level which is more common during air masses that are very moist. The freezing level will be on the high side today Monday and through Tuesday night.  As a result, precipitation will fall mostly as rain or snow or in town as the freezing level remains well above 8500 to 9000 ft.

Monday night and Tuesday would be best chance of accumulating snowfall at 8000 to 8500 feet. But being that the roads are so warm, there will likely be just some slush to deal with over the higher elevations of town.  Snowfall amounts will be in the 1 to 3-inch range Monday night into Tuesday, mainly the Village west. It will be especially breezy to windy, through the middle of this week.

On Mammoth Mountain, the guidance suggests that between the period of Sunday the 16 and Thursday the 20th, the upper mountain may get 2 feet plus at elevations above 10,000 feet. It will be wet snow at the main lodge with amounts more in the 8 to 12 inch range This is not from one storm. Rather the combination of three between Sunday night and Thursday evening.

It is important to mention here that this week’s storminess will be followed by a beautiful Spring weekend with much above normal temperatures. However, the European model runs still favors more unsettled weather the following week. The American Model the GFS is dry for the same period.   Whether a storm for week 2 shows up or not, expect an update on that later this week. Comment: (Does it not usually storm on the fishing opener?)   As a note, the Dweebs feel there will be a few storms in May and possibly June as well. We have yet to see the Cut-Off lows over the Great Basin develop this season. They will show up eventually!

 

Weather Discussion:

The blocky pattern over Alaska currently in process suppressing the upper jet stream south over Central CA will be retrograding westward later this week.  This change in pattern usually signals a northward shift in the upper jet stream and an extended period of fair weather for California. There is even the possibly of our first real Spring thaw for the Eastern Sierra this upcoming weekend into early the following week with highs near 70!  In the meantime, it will be windy this week until that change in pattern mentioned above kicks in.  I expect high temps to cool to the upper 40s through mid-week then a warm up through the weekend.

Unsettled Weather Pattern To Continue this Week….Ramping up next week with “Potential” for AR….

Snowfall Forecast for the Wednesday Night Thursday system:

2 to 4 inches in Town with 4 to 8 inches over Mammoth Mt

Best Accumulations will occur by early afternoon Thursday.

Light accumulations through Thursday night with snow showers.

*Climate Forecast System Shows potential for significant “AR” next week

While European Model forecasts another 4 inches of water possible over the crest by the end of next week.

*

 

 

From Mondays Mornings Weather Letter:

In writing this Mondays Weather Letter, I cannot help to think back to the beginning of fall in October, when the first storms hit the Eastern Sierra. I find it so fascinating that the drivers of the great winter of 2016-17 are still ongoing now since last fall. “Except of the change of ENSO”. I still see the same Teleconnections driving the storm track into California today. The same ones that brought us the big sierra storms of yesterday. I know that if it were January or February now, today, instead of April, we would be getting hammered by the same pattern that has been with us all Winter and most of the Fall.

I am beginning to think about next winter. In doing so I will focus more on ENSO. The EL Nino Southern Oscillation. Many ocean climate scientists will be extra cautious this year in forecasting a significant EL Nino because of the bust of the winter of 2015/16.  Nevertheless, weather dweebs like myself are watching important changes in the sea surface temperatures, now affecting the Indian Ocean off the coast of Western Australia.  Very cold water has formed in that region along its west coast. Cold water is denser than warm water and the winds will flow east toward the warm waters of eastern Australia. I will be watching to see if this colder than normal water works its way south then surrounds that country to the north along its east side.  Westerly wind bursts may develop from the Indian Ocean , associated with the MJO this Spring and Summer along the equator, sending Air Sea coupled Kelvin Waves eastward toward the central eastern pacific. This subsurface anomalous warmth is what El Niño’s are made of.  I’ll be focusing on this later this spring and summer, sharing with those that are interested via my Dr. Howard and the Dweebs report.

The forecast this week shows, a pattern early in the week with the upper jet mainly to our north. So today Monday should be another nice weather day. Winds will pick up Tuesday as a small system comes through, bringing the chance of some showers. On Wednesday, winds will pick up as well as increasing high clouds. Both the subtropical jet and polar jets do become confluent west of Santa Barbara well off shore. This is a different set up compared to many past storms as the bottom of a large scale trough that is confluent with this upper jet moves into Central California. The front left exit region will favor Northern CA and Oregon while its right rear entry region is focused upon the Central Sierra. Without a lot of subtropical moisture, this set up is not good for a big snow storm moving into the sierra Wednesday night and continuing into Thursday.  This looks to be a light storm, not associated with a Atmospheric River. Thus snowfall amounts will be much less than the storm that brought up to 5 feet along the sierra crest last week. It appears that amounts will be in the 2 to 8 inch range at this time.

One point worth noting, the long wave trough will remain over or near California over the weekend and into the following week. So expect unsettled weather and at least light snowfall on and off through the upcoming weekend.

With the block remaining over Alaska and the Bering Sea, the upper jet is likely to remain suppressed at times into California. So more storms are likely this month….