Although this weeks weather continues dry….Confidence is increasing that a pattern change next week will bring beneficial snows to the sierra and the beginnings to our winter snowpack

11:30AM Sat:

Both 12z EC and 12z GFS have about 2 feet painted over the Mammoth Crest by next Sunday AM the 25th. As mentioned below, the Friday system may have an AR connected with it.

 

SATURDAY MORNING:

Good Day Eastern Sierra! It’s a beauty!…Highs to day will be in the upper 50s with lows tonight in the 20s. Daytime high will cool to the 40s by Monday. With lows in the teens and 20s later in the week. The winds will be picking up next week and will become strong by Wednesday.

Discussion:

A closed upper high at 500MB was west of Washington State this morning with a weak belt of westerlies underneath to its south over Baja CA. We are in-between and that means little change in the weather this weekend. This weather pattern offers strong valley inversions and warm temps for this time of the year at resort levels. Daytime highs at 8000 feet will range in the low to mid 50s  Saturday and Sunday.

Next week the upper ridge builds NW to AK and the westerlies under cut with a long wave Trof setting up off the west coast. this will initiate a cooling trend and snowfall by Wednesday afternoon.  The Dweebs here have been forecasting this for over 2 weeks now. The first storm will arrive by  Wednesday afternoon and it looks like a moderate precipitation producer with over 6 inches in town and over a foot on Mammoth Mt….I will fine tune on Monday.   There are several other systems coming in through the holiday weekend. The GFS is painting some 2 feet over the crest by weeks end. The ECMWF is now dryer than that as one of the storms is omitted. So that is why the hesitation in the forecast at this time as we are too far out to pin down “amounts”, Either way, odds are very good that well see between 1 and 2 feet on the upper mountain by week’s end as the first system alone looks to bring 1 foot+ over the crest. the good news is that is it now coming in much more consolidated (less splitting)  in this mornings 12z run.

Additionally, The GFS has the Friday system with an Atmospheric River connected with it.  It looks warmer than the Wednesday night system but more moisture leaden….

 

The Dweeber…..:-)

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Friday AM Update:  GFS has come into line with the EURO as far as timing, however it is still not as moist as the EC through the end of next week.  Just to put an estimate on snowfall amounts, that I am sure will change by the time we get to Thanksgiving, it looks like 12 to 18 inches over the crest by the end of next week and about half of that in town above 8000 feet. This is looking like a moderate snowfall producer  (6-18 inches)

 

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

 

Forecast remains on track.

Differences still remain in the global models whereby the European model is still a lot faster in getting the precip going than the GFS. In fact it is a day quicker today, whereby it develops precip early Thursday morning vs the GFS which is dry for our area until Friday morning. The 10 day precipitation QPF reflects this as well as the Euro deterministic, as it paints over 2 inches of H2O over the upper San Joaquin drainage while the GFS is half of that. However, there is another storm on the way that may get it there by the following day or so.  So by today standards time wise, this looks to be a good couple of storms for Mammoth Lakes bringing a healthy amount of snow by the end of the Thanksgiving weekend or just a day or so later.  At least for down here in Southern Mono County. I would not want to down play this storm at this time…

What is interesting is that the European, spins up the subtropical jet over Southern CA Thanksgiving day as it lifts it north from Baja. The upper jet becomes confluent with the polar jet over that 24 to 36 hour period. That is most likely where it is getting all the QPF it paints…

It always a bit scary to go out on a limb and call for a series of systems that will bring beneficial snowfall to the high country some two weeks out. Especially when we have been dry since last Spring.  The climate CFS, (climate forecast system) has been touting this change for 2 to 3 weeks now and I have to say that as of this time, they have done a marvelous or even miraculous job! To get to this point time wise with a forecast some 2 weeks ago to week’s 1-2 is nothing short of amazing.  Now it is true that we are not there yet and we still have about a week to go. Certainly, stranger thing’s have happened, but it sure does look good for a couple of storms that would bring “at least” moderate snowfall by the end of that holiday weekend and just beyond from this point in time to Mammoth Mt.

The forecast two weeks ago was a combination of the CFS and “pattern recognition” without any global numerical guidance. With this method, you can not predict how much snow you will get, or when it will storm. However, you get the opportunity for a pattern change that offers a better chance of storminess during the colder time of the year.  Looking at pattern recognition,  that fact that there was so much cold air over the mid west and the east that was not progressive, actually held the ridge over CA and off shore. Now that the cold air and upper toughing is moving out away from the CONUS, the ridge is starting to weaken. Sensibly, that is why were getting high cloudiness on and off for the remainder of this week.

 

As a note, during drought years when the east is buried in snow and cold, it’s often is times like this when this big cold trof moves out for just a week that we get a storm or two. However, during the dry years, this is often the only opportunity to get precipitation into the sierra.  It is worth mentioning that this year’s El Nino will be at work. It is still not known if this Modoki with be wet or dry. One thing in our favor is that anytime you have a decent El Nino, it activates the southern stream.  And….It is the southern stream that can flush out the cold air and even displace the PV or Hudson Bay low eastward enough to create the excessive wavelength that we on the west coast just love. Excessive wave length usually = weak west coast ridge.

 

 

Dr Howard and the Dweebs………….:-)

 

Upper ridge axis has moved on shore over Northern CA…Upper Ridge will Weaken this week leading to variable high cloudiness…Expect little temperature change through Friday…….Through the weekend ridging will occur west of Washington State while a weak belt of westerlies moves into Southern California….

Wednesday AM:

There were phasing issues with the 12z run of the GFS…..Waiting for the ECMWF this afternoon.

Still too soon to predict how much snow in the high country for the following weekend..

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3:00 PM Tuesday the 13th

It is really exciting to see everything coming together nicely in the ensembles…..The pattern looks like it will deliver at least two weather systems for the Central Sierra over the Thanksgiving holiday and weekend. Although the 15 day precip amounts suggest a couple of feet over the crest, amounts will change from run to run and day to day.

More than anything else, it is the trend at this perspective in time that is exciting….:-)

 

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Another dry week is expected this week. Temperatures will remain in the 50s for highs, while nights at resort levels will stay in the upper teens and 20s.  The forecast progs show our upper ridge now pushing into California and weakening. This is allowing high cloudiness to move into our area. The Dweebs expect variable amounts of high clouds through Friday.  By the weekend the northern portion of the ridge redevelops off the coast of the pacific NW while a weak branch of the westerlies develops off shore into much of the southern 2/3s of our state.. This I think is the very beginning of a change to our pattern for California, one that will evolve next week. The southern branch of the westerlies will develop further and bring a chance of some light precipitation to Southern Ca. At this time, the models are struggling with the amount of energy the southern stream gets for the first half of next week. At the moment, whatever it gets it is not likely to effect the Central Sierra much if any.  It still appears that the weather system or short wave that hold the most promise for the Mammoth Area will occur between Thanksgiving and the end of that weekend.  The Dweebs have been touting this for a while now.   The European has been the most consistent with it. Now the latest 12z GFS has more to add to it. However, with all this said, there is still, too much distance in time to try to pin down on whether it will bring 3 to 6 inches of snow or 1 to 2 feet.

Stay Tuned……………………….:-)

Chilly Northwest Sliders has put snowmaking on Mammoth Mtn into high gear….Althrough it is another Dry 5 to 7 days ahead…a few NW sliders will keep it chilly……Who’s afraid of the Modoki El Nino!

Monday Night 11:10pm

Both 12z GFS and ECMWF have run.  EC ensembles have not run yet.

It will be very interesting to see which model does the best next week.  Huge difference between the two at this time.  I still favor the ECMWF as it has been more consistent. It is the wetter scenario. New deterministic says 1 to 2 feet by Friday over the crest.   Again this is a long way out and the GFS is pretty dry for us that same period…

 

Monday Afternoon November 12th

 

Just to add some confidence to my forecast for next week, the new 8 to 10 Day outlook just out, goes wet for the Southern Half of California with the bullseye for Southern CA. The Central part of the state has precipitation during the period, but dynamically, the emphasis is LA  and San Diego.  The upper jet favors Southern CA with a Southern Stream jet.  Just to add misery for the fire victims of the south, this southern stream may be the theme of the winter, once EL Nino kicks in. So areas below burnt foothills and canyons should definitely start thinking about sand bags for future storms this winter….

 

Monday AM;

Just to reaffirm;

Although there my be mixed signals from various forecasters for storms during the week of Thanksgiving, the Dweebs are still viewing this time frame of transition out of the dry pattern of the Fall to one of wet. In the post below, it was stated that the storms would be in the light to moderate range, however, we can not rule out that something more major is brewing as well.   The two global models that most meteorologists use as forecasting tools show a system about Tuesday for Southern CA and again later that week. The GFS is not as strong with the second system between Thanksgiving and that following weekend as compared to the European.  The point here is that looking at the deterministic version of the European, it is showing some 2 to 4 feet of snow by that end of that week while its ensembles are showing some 12 to 18 inches. I prefer the Euro over the GFS in this distance of time. As stated below, we will have better visibility later this week. The idea of a small storm seems to be getting less attention in my estimation by the end of Thanksgiving week. We have a long way to go time wise and the models will be adjusting a lot with each run so the way to play it is, that it look good for a storm or two but the details still have to be worked out as far as how much and when.

Of note;

Once we get into this pattern change, the climate models (the CFS) keeps it wet through the 9th of December.

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Sunday 10:35AM

We’re still a go for snow during the week of thanksgiving.  Nothing large…..Light to possibly moderate snowfall for the week.  Visibility increasing this week for the next week in both the ECMWF and GFS..

 

Dr Howard and the Dweebs…………….:-)

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Saturday 10th; 1:30PM

 

Long Range continues to evolve with global models picking up on the change. Both ECMWF and GFS and GEM Ensembles are the strongest with the trough the end of the week following Thanksgiving. The models will change throughout the next 10 days on this pattern. You never know it may be pushed back, but so far so good!

 

The Dweeber…………………..:-)

Friday AM:

Still nothing convincing yet in the ensembles from last night, however, the Climate Forecast System shows it wet during weeks 3 and 4.

Click on the link below then click on weeks 3 and 4 precipitation.

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/weekly/

New 12Z Global model runs show bulk of cold air pushed off the coast of upper New England by the 15th.   Global models should have good consensus of the Thanksgiving week by then.

The Dweebs are still holding on to the period Sunday 18th through Sunday the 25th as being potentially stormy.

 

Climate Outlook for winter 2018-2019  PDF  (Pioneer Model) Last year and this year

https://bluehill.org/Winter_2018-19_jd.pdf

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Thursday Night the 8th…11:15pm

Global Forecast Model beginning to trend with the Dweeber’s idea for a storm about the week of Thanksgiving. Both deterministic runs of the GFS and GEM show a nice little Trough the weekend before Thanksgiving. The Deterministic EC does not agree. Will check in the morning and see what the Ensembles of all these forecast models show….Remember, once the bulk of the cold air gets close to moving off the east coast, there should be an adjustment in the models….Stay tuned….update in the Morning…..

 

……………………….:-)

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Latest NW slider has dew point now down to the Single digits. With high temperatures in the 30s and low 40s on Mammoth Mt,  That is going to be very good for almost round the clock snow making. Although daytime temps will rise a little over the next few days, another NW slider will bring more shill Saturday night into Sunday.

 

Lots of talk about the Modoki El Nino this year.  As with most weather signals, as they relate to our winters wet season, the Modoki El Nino is not 100% for a dryer than normal winter. Most of you know the big winter years of the past like the winter of 1978 and 1969. Here is a list of Modoki El Nino years and you will see that we have had some big-big winters with the El Nino Modoki…..Also some pretty dry ones too,

These are the basic Modoki Winter years and precip associated with it from various sources.;

LA Rainfall                  SFO Rainfall                 Mammoth Mt Snowfall inches                      Winter of

21.13                             10.46                                 Unknown                                              1957 1958

7.93                               22.29                                 Unknown                                              1963 1964

20.44                             29.41                                 Unknown                                              1965 1966

27.47                             20.80                                 Unknown                                              1968 1969

7.66                               17.44                                  196                                                       1986 1987

21.00                             26.66                                   226                                                      1991 1992

22.29                             24.35                                   540                                                      1994 1995

20.80                             16.49                                   356                                                      2002  2003

17.44                              37.25                                  570                                                      2004  2005

 

As you can see, Los Angeles has had above normal rainfall,  7 out of the last 9 Modoki winters. (AVE- RF) 14.93

San Francisco has had “about” 6 out of the last 9 Modoki winters with average to above average rainfall.  (AVE 23.64 inches)

 

Now for the good news!

The Pioneer Model which does a very good job in forecasting 500MB Heights, shows this for this winters analogs winter years in its winter forecast.

Here are the new analog data set recently released:  This means in simple terms, the winters that most resemble pattern wise what this models forecast is;

1963/64, 1965/66, 2009/10, 1996/97, 2013/14, 2004/05, 1968/69, 2003/04, 1977/78, 1966/67. 2003/04 and 2013/14.

Winter of;

1964  dry

1966  Wet

2010  Wet

1997  Wet

2014  Dry

2005  Wet

1969  Wet

2004  AVE

1978  Wet

1967 Unknown for Mammoth….Wet in LA and Dry in SFO

2004   Average

2014  Dry

*Dry means more than 85% to 90% below normal; This is my criteria in this report, not the standard

Wet is 110% of normal or greater; This is my criteria in this report, not the standard

Odds are, based upon the Pioneer, Model, we stand a better than a 60% chance of an average to above average winter even counting the Unknown as dry.

 

There is no question in the Pioneers model forecast that the western hemi 500MB config is an El Nino with a strong southern stream developing sometime during December and hitting California top to bottom in January. Otherwise it favors Southern CA December and February up through the Southern Sierra for greater than normal precip. Again this is a model forecast, however, not set in stone.