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.

 

Storm Door Closed?…….Don’t look to the West…….Look East….

Wednesday AM:

Forecast remains on track with a chilly NW slider bringing breezy cooler weather to the high country Thursday. Highs will cool to the 40s on Thursday with nights in the teens and 20s there after. The weekend looks fair and dry with seasonal temps.

Longer Range is well discussed in the past two discussions’. Cold air in the east must more out over the Atlantic to open the wave-length. This looks likely to occur during the week of Thanksgiving. It is unknown at this time, the timing of the first storm that week.  However, most likely between Thanksgiving and that following weekend.

 

The Dweeber…………………..:-)

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Tuesday AM:

The discussion below gives a good explanation of why it is dry in California. Sure, there are underlying reasons for the current pattern that are more climate driven and involve other types of teleconnections.  However, for the rest of this discussion I will discuss this weeks weather which is also important from a snow making point of view.

It appears that the warmest weather of the week is over for the time being. The wave length that exists this morning includes a sub tropical upper level ridge west of Baja, MX. The high is ridged negative tilt to 140 West all the way into the Gulf of AK.  The polar jet on the North East flank of the ridge sweeps SE through Washington State, to the Central Mid West then NE through New England via the Great Lakes states. Over the next 3 days, polar air will sweep south through the northern plains deepening that trof, so that by this Friday, deep polar air with 1000-500mb Thicknesses down to 504DM will enter the US via North Dakota and Wisconsin.  Shots of snowfall will occur in these areas this week and will intensify later this weekend.   Through this process, a dry cold front will sweep through the Great Basin and the Eastern Sierra Thursday Morning, bringing wind over the crest, breezy weather to the lower elevations and a very dry chilly air-mass.  This is a dry pattern, but will greatly enhance snow making conditions on Mammoth Mt as the week progresses with Thursday the best day for round the clock snow making.

This morning I am of the opinion that we will have a good storm or two between Thanksgiving and the end of the Month. It is possible that it may occur sooner, but better odds after the movement of the Eastern CONUS Trof off the east coast around Thanksgiving….  The new updated ECMWF EPS 45 day outlook arrives later today. I will post in Wednesday morning as it relates to our area…

 

Dr Howard and the Dweebs……………….:-)

 

PS. Thanks Tom for sharing your insight.

 

 

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I have to remind myself that this is November. I am still wearing short sleeve shirts to work and even through it was getting dark when I left the office late this afternoon, I did not need a jacket!

The pattern across the Pacific is one that features lots of splits and cutoff lows in the flow and a ridge in the mean off the west coast.  Although there has been an active pattern at times in the Pacific Northwest, California and much of the west has been out of it.  If you want to see part of the tail that is wagging the dog, just look at the 6 to 10 day temperatures outlooks. It shows a lot of cold in the central and eastern sections of the US. This cold is part of a big east central long wave Trof that assist’s in the block effecting California. This block is a high pressure ridge off the west coast.  In order for the west coast ridge to weaken, the cold anchoring Trof to the east has to move off shore to open the wave length. Once the wave length opens, the pattern of westerlies across the pacific is likely to become consolidated and west coast storms are likely to move south again into California.  Will this happen, yes!  When;  good question? So without any meaningful deterministic guidance that shows good probably in time, lets see what the ensemble’s of the global models showed today.

 

The GFS (American Models) ensembles are showing the east coast cold moving off into the Atlantic by the 17th.

Euro (ECMWF) ensembles shows the major source of cold moving off into the Atlantic about the 15th with another shot about the 20th.

The Canadian seems to be the fastest in consolidating the flow across the pacific.

The main message here is that all the global models seem to be moving the cold in the central and east, off shore. They are just different in timing.  The Canadian suggests that the change in wave length looks more likely the weekend before thanksgiving and the others around or by Thanksgiving itself….

In the meantime, enjoy the weather now, then be ready for a gradual cool down this week.   Better conditions for snow making ahead….…:-)

 

Dr Howard and the Dweebs………………….:-)