Archive for year 2021

Breezy Cooler Weather this weekend with a hint of snow Sunday……More unsettled weather the early part of next week with Light to Moderate amounts of snowfall expected Monday and Tuesday…

 

Monday night the 8th

Rfc has cut back on QPF to 1.35 inches over Yosemite.
Strong winds are buffeting Mammoth tonight.

Snowfall on mammoth mountain likely lower end of forecast or about a foot.

2 to 6 inches possible in town; will up date in the morning.    Note; very unusual the way models are so inconsistent  with QPF.

Additional Comments   Sure do love the large SSTA  pool near the dateline.  WPO in negative phase.  Good for more AR’S in the future.

 

 

Sunday AM PST 9:30AM

Best part of the time change for the Met is that the models come out an hour earlier!!

This mornings model runs have the freezing level going higher. Why? Little in the way of upstream amplification.  so storm lacks cold air at our latitude.

I think that if you look at the teleconnections and focus upon the WPO region, you will get a glimpse of the tail that will wagg the dog for the next 2 weeks.  This is a high latitude block and although it does not stand out like a sore thumb, it does make you think about the possibilities of what’s connected to it and the results thereafter. Might it be related to the warm SSTAs over the mid high latts between the dateline and Hawaii? Cold air is pouring south, east of that block creating Jet “O” Genesis down stream. The wave length suggests future ARs for the west coast over the next few weeks. So, long fetches of moisture headed for the west coast. However, it remains to be seen if there will be a lifting mechanisms to be beneficial.

MJO: Is expected to progress to the Western Pacific and so prospects for a pretty good sized west coast ridge (+PNA)should result the weekend of the 15th. The ridge is not expected set up inland and so highs will warm to the mid to possible upper 70s by next Saturday in Bishop…..Low 90s possible in Death Valley……mid to upper 60s in Mammoth. 80s LA?

 

The word for the late Monday night and Tuesday storm is that it will be wet; will have high snow levels. Best Accumulations above 9500 feet. Snow level mostly 7500 to 8500 feet. Expect between 15 and 20 inches above 9500 feet. Main Lodge 1 foot+  Town ?

 

 

 

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8:47am Friday the 5th

Models continue to struggle with AR with it being on again, off again and now on again!   Not sure why….Although it will not make a difference on whether we get cooler, windy and have snowfall. It does make a difference on how much it will snow. With out the weak AR, this weather system is probably good for 5 to 10 inches of snowfall.  With it, between 1 and 2 feet over the crest. Dweebs will tprecip will occur.  another look at it tomorrow.

In the meantime, the new seasonal ECMWF forecast for both precip and temperature is out.  Not much change expected for November and December with a slight bias toward above normal snowfall. January came in a bit wetter with the odds tilted toward normal, instead of below normal precip. February is still showing drier than normal precipitation and March is now a bit drier than normal compared to a bit wetter than normal.

The forecast for this weekend is for breezy weather and periods of strong winds over the sierra crest.  It will grow cooler with highs returning to the low 50s cooling to the upper 40s Sunday and lows in the 20s. The is a chance of some light snowfall later Saturday night into Sunday AM with an inch or two of snow possible over the upper elevations Sunday AM. The main upper trof and weak AR come in late Monday night into Tuesday. Expect moderate to strong winds with this system, with further cooling expected with highs in the low 40s Tuesday. The storm rolls out Wednesday with a warming trend into the weekend…

 

Dr Howard and the Dweebs…………………….:-)

 

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This mornings operational and ensemble model runs continue yesterdays trend of removing the “categorically” weak AR, previously expected for this Tuesday. This will have the effect of cutting snowfall amounts in this case to about 1/2 of what was previously expected. The Dweebs believe that somewhere between 6 and 12 inches of snow is possible from the Monday-Tuesday “weather system” “at this time”.  The storm has a good sized long wave trof with several waves, (vort maxes) embedded within it.  As discussed in an earlier discussion, The amplification process over the western pacific was never set up quite right in the first place. Not sure why the models were so “Gung Ho” on the AR’s extension through the sierra.  As headlined; at this time, based upon RFC’s forecast between Huntington Lake and Yosemite, expect between 6 and 12 inches of snow above 10000 feet, and between 2 and 5 inches in town. The snow level/freezing level bounce up and down on Monday as each wave has a warm air pocket with it. Best accumulations for the Town will be later Monday night into Tuesday AM….

Extended Outlook:  The global models show a rather strong long wave ridge that builds into California, the 2nd half of next week, 500MB Heights rise in excess of 588DM over CA.   The record high temperature for Bishop CA on the 14th of November was 89 degrees set back in the year of 1906. It was one of the warmest days on record for so late in the year.  The Dweebs believe that although that kind of high temperature record rarely occurs so late in the year, it is very possible that Bishop could get into the 80s later next week based upon latest week 2 guidance.

 

I will have updated ECMWF seasonal outlooks tomorrow.

Here was seasonal outlook from October 1st. for Near Mammoth Lakes

November   Slightly above normal

December   Slightly above normal

January       Much drier than normal

February     Much drier than Normal

March         Slightly above normal

 

ECMWF weeklies ensemble show 3 to 4 feet of new snow by Mid December for our part of the Sierra.

 

Dry Weekend with Seasonal Temperatures expected for Mammoth….Potentially unsettled weather expected next week….Longer range outlook for week 2 have some good chances to add to the snowpack

 

November 3rd at 4:30PM

Models are really struggling today with the up stream amplification that drives the upper low south Tuesday.  If you read my early discussion Tuesday, I had in the Cons...The concern that the surface cyclogenesis off the coast of Japan is weak and out of place. That maybe affecting the models for the Tuesday system as the strength of the AR appears to be weakening again. I hate to yo yo, so lets wait a few more days to see how it all shakes out.

 

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Nov 2 update is at bottom of this discussion.

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The weekend of the 7th marks the end of daylight savings time. So enjoy one more week of the late afternoon sun before it all changes the following weekend. Now that we have snowpack in the high county, we no longer have the usual 20 degree spread in highs between Bishop and Mammoth. Our highs are closer to between 15 to 17 degrees difference now. High temps will cool to the low to mid 50s this weekend with upper 40s to low 50s next week. The latter is more typical for November.

Winter thoughts..

Three climate forecasters were interviewed by SFgate recently. None had any prognostication of a wet winter. Why, because were back in a La Nina. La Nina’s have a dry bias. True!.   With at said, there are Wet Nina’s too.  Although it difficult to say that this winter will be a wet La Nina, My Gut feeling is that it will be considerably wetter than last years La Nina, as there are some very important teleconnection differences this year over last year. Here are two biggies I believe;

  1. The Quasi Biannual Oscillation is in its Negative Phase. I have posted this before over the past several weeks so look at my achieves and read on.
  2. A very significant warm pool stretches well north west of Hawaii. The most comfortable place for the eastern pacific ridge is over the SSTA in the north pacific. The Dweebs Love the Warm H20 pool there and the cold pool in the Gulf of Alaska. Great Team!! Check this out!!  https://www.ospo.noaa.gov/Products/ocean/sst/anomaly/index.html

The Dweebs believe this Winter will be quite a bit wetter than Last!!  The eastern pacific ridge in this position favors more positive tilting long wave trofs which favors more AR’s  The QBO in its negative phase favors more Strato Warm events I have read.

 

Back to weather;

Over next 10 days there are a couple of trofs that will bring at the least some light snowfall. 1st, a high latitude block develops over Western Canada on Halloween. There is a system that will under cut that block next Thursday. Mainly light snowfall is expected.  Light (1 to 6 inches)  The block breaks down over the following days as a much larger storm approaches prior to the 10th. This storm “may” have an AR as the upper jets rear right entry region favors CA.

Tuesday 11/2/2021

Quick Update;

The Weather system expected for CA Thursday will be focused upon Northern CA with little effect for Southern Mono County, other than wind and cooling. At the Moment, I do not expect anything measurable for Mammoth Lakes precip wise.  With that said, Northern Mono County may get some light rain and snow above 9500 feet.

Pros; The next weather system being touted by the GFS model for next Monday, Tuesday and Wednesday has a weak AR with it. Tuesday seem to be the day of heaviest precip. So expect a storm with the potential to bring a few feet of snow over Mammoth Mt then.

Cons; The ECMWF model is much weaker with it and shows no AR for our area. Additionally neither model has the Surface cyclogenesis over the western pacific in the right area for ideal down stream amplification.

So the Dweebs are cautiously optimistic about the early next week storm.

Update this Friday….

 

11-02-2021  1:52PM

Just viewed new 12Z ECMWF operational and Ensemble

They have come in line with GFS for Weak AR,  next Tuesday of next week followed by Dynamic Trof and Upper Jet.  Upper jet at 250MB is as strong as 150knots and its latitude in low enough to give Mammoth a good Whopping.

Snowfall Amounts over upper elevations will be fined tuned later but will begin with a couple of feet by next Wednesday over Old Wholly.

 

Dr Howard and the Dweebs………….:-)

Strong AR headed for California this weekend with Copious amounts of moisture to work with Dynamically…..Snow Level to remain high until the cold air arrives late Sunday night……

Sunday 8:10 AM

 

Everything on track for excessive wet event for October.  Accumulating snow probably Monday Morning in town. Freezing level down to Village about 800AM to 900am Monday morning.  This is a little earlier now than Fridays guidance. Amounts still look good for 3 to 5 feet above 9,000 feet now as snow level is down about 500 feet during moister portion of event.

Remember, in order to break snowfall record for October, we need close to 68 inches at Snow Plot as there was 18 inches already fallen. Water content is likely to be there either way so precipitation should be enough.

What a way to kick off the water year beginning with October!!!!

 

9:00AM Update

Latest IVT guidance (GFS) from Scripts IVT puts the October 25th Event in the strong category now as compared to the January 27th event which was moderate, west of Mammoth Pass. The January 27, 2021 event dumped aprox 10 feet of snow on Mammoth Mt. However, this storm is much much warmer. Freezing level above Yosemite is between 9000 to 11,000 feet during the day Sunday during the beginning of the event. However, by Sunday night and especially after midnight, the freezing level begins to come down as indicated;  11:00PM (10,200ft) down to (8900ft) by 5:00AM Monday AM.  Between 5:00AM Monday and 11:00AM Monday 8900 to 7100ft. Then 11:00AM Monday to 5:00PM Monday; the Freezing level goes from 7100 to 6700 feet. Then from 6700 to 6100 feet Monday night.   It is important to realize that in an saturated airmass,  the Freezing level is close to the snow level, within 500 feet. contrarily, micro physical processes can allow snow to fall much further down in elevation from the dendritic growth zone, if temperatures are cold enough in that zone and the vertical motion is favorable.  All in all, the main point is, precipitation for the Month of October may be historic for Mammoth Mt, whether we get the additional snowfall of 68 inches in addition to the 18 inches the mountain has already received.

 

Next update Sunday AM……………….

Dr Howard and the Dweebs…………………..:-)

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The stage is set for a good wholloping AR for California this weekend. The updated GEFS IVT plume forecast shows a magnitude for the coast, from the 06Z data at the mouth of the Bay Area, approaching 1200 (KG) (MS) which is in the extreme category for the (IVT) Integrated water vapor transport. For our part of the Sierra, it shows about 900 (KG) (MS) for the IVT, in the strong category.    This is on par with the January 26th-27th, 2021 AR. This AR will give relief to the many reservoirs throughout Central and Northern CA,  However, what about the mudslide threat for areas below the burn scars? Now I will say that the ECMWF model is not nearly as wet.  However, if you average them out it is still very impressive!

The Models are coming in line with some 5 to 7 inches of water for just west of the Mammoth Sierra Crest. The freezing level is high to begin with. So although the snow level may begin lower, it will rise to between 9,000 to 10,000 feet initially. However,  once the cold air induced vertical motion begins, the snow level will come down into the town Saturday Night or Sunday, then into Monday.   Expect excessive snowfall for October, with potential “Event History” in the making for record snowfall on Mammoth Mt.  The current record is 85.6 inches during October of 2004.  So far this October, Mammoth Mountain has received 18 inches.  Only need another 68 inches of snow by Halloween to break the October record.  This should be a 100+  year record for October based upon precipitation records for the Sierra dating back to 1895.