Archive for December, 2014

Merry Christmas from the Dweebs…..Weather to turn blustry later today and tonight as Chilly NW Slider moves in quickly this afternoon….WX Pattern to Become More Amplified Next Week with Insider Slider Pattern likely…..

1:53PM   It’s Currently Snowing in Mammoth Lakes!! 

 

Most QPF models are pretty much the same, calling for about 1/2 inches of moisture for this area of the Sierra. However, HPC is touting an updated  3/4 of an inch for the crest, Day 1 QPF.   HPC has a habit of being a little on the “Wet Foot” side, so will stick with initial snowfall amounts of up to 8 inches over the crest and hope for more.

That means that the Town should be in for a good 3 to 5 Inches overnight. With that said, CRFC is calling for a 1/2 inch of moisture in the Yosemite area. With a system with Orographic’s like this one, the Dweebs will often times double that for the water EQ. Now …..in that most of the snow will fall after the cold front, “FROPA” in the colder air; And…..considering snowfall ratios are expected to average 13:1 to 14:1, we may end up with a present surprise Christmas AM in the upper elevations of more snowfall than expected or even the town..

Longer Range:

Next week the upper air pattern with really begin to amplify. At the same time, some retrogression will be under way. The eastern pacific ridge wants to slowly retrograde to about 135W to 140 West. This location, this amplified, this time of the year, can bring some of Mammoth Coldest weather. The Dweebs would not be surprised to see below night-time below zero temps developing around the New Years Holiday.   At this point in time, it is not clear of the storms track and if the systems will be either inside sliders or outside/coastal sliders. Several ECMWF and GFSX ensemble members have shown the development of an Modified Arctic Upper Low that develops over Northern CA and drops south about the end of the year or within the first week after.  The location of this system will be key to snowfall here in the Eastern Sierra.  Additionally, folks in the Owens Valley will need to follow the weather later next week as if this cold system as cold as it looks gets close to the coastal water of Paso Robles or Santa Barbara, this would have the potential of pumping a lot of snow up the Valley.

Comment: This is not a forecast at the moment, just discussion on the possibilities……

 

Dr Howard and the Dweebs……………………..:-)

Winter Solstice has past….Monday is Winters 1st full Day…Christmas Eve/Day System looking stronger this evening as GFS Sides With ECMWFs Further Westerly Track….

Christmas Eve:

Snowfall Forecast 3 to 5 inches in town between 6:00PM and 1:00AM Christmas Day

5 to 8 inches over the upper elevations…..

 

1:10PM Tuesday Update:

Models have come in a wee bit drier this morning but based upon QPF we should still get about 6 inches on the Mountain.  3″ to 4″ in town.   The fact that this is a cold storm and most of the precip will fall after the front, giving a higher Snow to Water Ratio.  The Snow to Water ratio will average about 13:1 to 14:1, Not Platinum Powder Alert Criteria but still light and dry..  So if we get .5 inches of QPF,  that would be about 6 to 7 inches of snow over the upper elevations.  CRFC still shows .47 for Yosemite by 12Z Thursday and so close to 1/2 inches of water. As far as timing…most of the snowfall will be over by Midnight because of the speed of the short wave.  It’s a Screamer!  Update either tonight or in the morning…..

 

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

 

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2:00PM Update: Just looked at the new Experiential T1532 1800Z GFS which shows PWAT of between .8 and inch within the Front.  The system’s Vt center is also digging into CA about 150 Miles further south.  This is really in step with the ECMWF now. WOW the EURO is so good!   HPC has just come out with between .5 an .8 on the QPF.   CRFC has between .4 and .5 for Yosemite.  With good Orographic’s you can often times double that. So here we have a system that could dump in a short period of time about 8 inches over the crest and 6 inches at the main lodge. In town 3 to 6….

 

 

12/22/14 UPDATE:   10:00am

 

The GFS has continued its new trend in a further westerly trajectory of the Christmas Eve short wave. The main idea now is to highlight that this is going to be a quick hitter. I.E. It moves in quickly by 9:00PM Christmas Eve and it moves out Christmas Day. There is still some coupling of the two upper jets to give it an extra shot of moisture and energy but it does not last long.  Expect this to be a windy system with the winds picking up during the Day Christmas Eve. Gusty Winds in the 45 to 55 MPH range in town is possible as the system still has a WNW bias with the upper jet. Most of the precip is post frontal.

The Dweebs Estimate about 3 inches in town and between (3 and 6+) inches over the upper elevations by Christmas Day if the Deeper ECWWF verifies.  Highs on Christmas Day will be some 25 degrees colder than todays high of 56 predicated at 8000 feet.

PS

 

Per Vegas Discussion for those traveling the Owens Valley Christmas Eve:

Winds should start picking up Christmas Eve afternoon and strengthen during the evening where a 100+knot upper jet at 250MB moves directly over head. 500 MB Heights show a “hydraulic jump” signature to the lee which looks probable for a Christmas Eve Downslope Wind Event for the Owens Valley and Fish Lake Valley.

The Dweeber………………………………….:-)

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Welcome to Winter…  It is officially here over the Northern Hemisphere.   While we dream of the deep snows to come this winter, we’ll actually have a few very mild days to begin the week as a strong anticyclone sets up just off shore.  High temps will range in the upper 40s to low 50s the first half of the week while night-time lows will be in the upper 20s and 30s.

The good news this evening is that the GFS which had been consistent the last several day in keeping the next weather system for Christmas further north and east has flipped this evening to the ECMWF idea all along.  The Dweebs were just commenting a few days ago how the GFS had the right idea for quite a while. Tonight, that idea appears to be incorrect.  The fact that the change is coming within the 72 to 84 hour period raises a higher level degree of confidence that the short wave will remain on this track. The track is much further west with brief but over water trajectory. And…..this one does not split. In fact it comes right through the Sierra early Christmas Day.

The Dweebs looked at the Winds aloft at 300MB and there appears to a coupling of a small subtropical jet with the polar jet just briefly off the North-Central CA Coast before it swings inland to the sierra. The upper flow at this time is southwesterly for a short period of time. So there is a period of orographics for about 6 hours.

The Dweebs will looking again in the morning at both 06z and 12z to see if there is consistency. If the short wave holds this evenings course,  we may end of with quite a bit more snowfall over a short period of time. Like 6 or even 8 inches of snowfall between Wednesday night and Thursday Night.

Stay tuned to this developing weather system that apparently is changing course.

 

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

One more system to move through the Sierra Friday into Saturday…Then a fair weather stretch…..Christmas Day Storm still Lurking…..

Saturday 12:30PM

Mammoth Pass to date has “about” 3.5 inches of water in the rain tip for the season.    Compared to “about” 4.5 this time last year.  So this year we are still behind, water-wise last year at this time.

A Quick update to indicate that Mammoth has indeed received between 1/2 and 3 inches overall, between the village and the crest.  A northwest flow aloft is providing the path for over running from the Pacific into CA. The off shore ridge will eventually take over Sunday into Monday. It then gets squashed Tuesday into Wednesday allowing an inside slider to bring winds, cooling and some snow showers to our region.  Models have been struggling with the track of the Christmas Eve/Day system the past several days. The GFS seems now to have the best handle with it. The EC seems to want to dig it too far to the west.

The main message here is that no major storms are in our outlook for the next 6 to 10 days….However, some light snowfall is certainly possible.   The night of lights looks spectacular weather wise; some cloudiness but nothing that will harm the show tonight for the fireworks.

Dr Howard and the Dweebs……………………..:-)

Friday AM Update:

The 12Z Thursday run of the ECMWF was just a one time “heart throb”.  However, one has to think about what it was looking at to come up with what it showed, just beyond the end of the year.  It may flip back. IE “AR”

Back to reality…..Today through Saturday AM will have some Snow Showers or light snow and the chance of some light accumulations by Saturday AM. We ridge up Sunday into Monday with clear sky’s and calm winds Monday into Tuesday night with a temperature inversion.   On Wednesday, Christmas Eve, we’ll experience increasing winds over the upper elevations with a Northwest slider approaching and the chance of some light snowfall Wednesday afternoon or Evening into Christmas day.  The Christmas Eve/Day System is small but potent. Its effects will be determined by how far west it digs.  The models do not have an entire handle on it yet but it looks especially cold…..

For the visitors planning a trip to the high country, here is your temperature forecast for the Town of Mammoth the next 5 days.  Note, I did not include Christmas Eve or Christmas Day because of a storm the will move into the west that may be quite cold. The exact track of that system is unclear at this time.. Also note that the morning lows are quite mild due to the inversion anticipated. These temps are forecasted for the elevation of the Village at Mammoth.  It will be much colder over the lower elevations of Mammoth and especially Long Valley including the Mammoth AP. So not be fooled by the morning temperature forecast put out for the Mammoth Airport for morning lows….It can be 10 degrees or more colder…..

                          High              Low

Friday                 35                  25

Saturday             40                 30

Sunday               48                 32

Monday             47                  32

Tuesday             47                  31

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

PS….  Just had a quick look at the New 12Z GFS for Christmas Eve/Day.  The model takes that short wave further east on this mornings run and so the outlook based on this particular model run will mean just wind and cooling that day.  Stay tuned as the Dweebs will be updating daily through the end of this year…..

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Thursday PM

For those of you that have access to the weeks 1 and 2 ECMWF Control.  Take a look at the new 12Z run today. If that does not get your hart pumping…..your probably a Zombie!

Update for the Christmas System,  is that it slides more inside….So Windy and showery and cold is more like it….

Thursday AM:

Weather systems over the past 6 weeks have built up a base depth of between 2.5 and 4 feet over Mammoth Mt. All ski resort corridors are now open including Little Eagle, Canyon Lodge and the Main Lodge. The Dweebs expect a few more inches of snowfall Friday into Saturday before we ridge up Later Saturday into Monday.

The Dweebs Weather update shows a beautiful today with lots of sunshine…there will be clouds as well that will increase over night. Breezes will be light this morning but increase tonight. The next and last in the series of weather systems will move through the sierra Friday into Saturday bringing light amounts of snowfall. Possibly a few inches. Thereafter, we go dry Sunday through Wednesday.

The next weather system for Christmas Eve and Christmas Day is being handled differently by the global models. The Euro brings a cold system down the coast with snowfall for the Eastern Sierra while the American models bringing some wind and cooling but keep the weather dry. Stay tuned to this change. I expect better visibility “in the models” later this weekend for Christmas Day!

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