Archive for year 2013

Upper Low Located Just southeast of Monterrey….To shift slowly ESE this AM….Then Slowly SE tonight…Snowfall to increase Later this morning for the Crest and Resort Levels…

10:00AM update:

Although the track of the upper low was forecasted to move ESE. The actual track is right down the coast so far. So it appears now that the crest will not benefit from any significant UVM.  Upslope is already beginning to show up on the wave loop and so will back down snowfall amounts for today to the 3 to 5 inch range along the Eastern Slopes of the sierra.  There will be an increase of NNE wind Monday AM, confined mainly to the crest.  We will ridge up Tuesday into Wednesday for some fine weather with milder temps!  Next colder system to bring light snowfall and breezier weather Thursday.

 

So far snowfall has been “mostly” confined to the north of the upper low, now located just some 50 miles ESE of Monterrey. This system will move very slowly ESE today then SE later tonight. However the system will not exit Ca until Monday mid morning. According to the new WRF,  it follows a path ESE to Bakersfield by 10:00am Sunday, then is located near Baker Ca west of Vegas by mid evening. It then drops SSE to the Parker Dam in AZ by Monday at 7:00am. This system never crosses the Sierra. However the circulation will favor the crest initially then wrap back around, and up the eastern slopes of the Southern Sierra as it shifts SE. This is a more difficult system to forecast snowfall. Not only amounts but timing as well.

So best guess at the moment is that the crest will still get the lions share as it usually does with 6 to 12 inches by Monday AM. The Town of Mammoth will get 5 to 7 inches, with 3 to 4 inches along the highway 395 corridor, especially along the southern half of Mono County. It may be that we get most of the precip in town from the back wash from this small system.

There does not look like any potential flight problems leaving Mammoth Monday. However, it might be a bit bumpy landing at LAX Monday PM as there is a 120knot upper jet that spins up on the upper lows back side Monday morning.  The San Gabriel’s Mts south to the adjacent valley may have a strong Santa Ana Monday AM as well.  We ridge up Tuesday into Wednesday with the next drier system effecting Mammoth Thursday.

The two most watched global models are going in different directions for next weekends short wave and pattern change. Now with a drier and not as cold scenario. However, for you cold hounds it will still be plenty cold!   Will up date over the next few days on that.

What the Dweebs are seeing is that the MJO is moderate now in phase 4. It is forecasted to translate into phase 5 next week then eventually phase 6. This effectively forces an extension of the Eastern Asian jet toward the west coast the end of week 2.  This may force the pattern over the CONUS to become progressive and eventually open the gates for wetter storms later this month. This is really a change in thinking…so will update as time permits….

 

Dr Howard and the Dweebs……………………….:-)

 

 

Cold weather to continue for the far west with next spliting system bringing light amounts of up to 6 to 12 inches over the higher elevations Sunday/Night..Weather to turn even colder by Mid Month….

12:00pm Saturday Update:

New 12z ECMWF is in and looking at 240 hours out, dumps all the cold air into the great basin like last nights GFS.

Now take a look at the 6 to 10 day outlook for the Great Basin…..Burr!!!

As well as the analogs: http://www.cpc.ncep.noaa.gov/products/predictions/610day/610analog.off.gif

Analog Temps probabilities… http://www.cpc.ncep.noaa.gov/products/predictions/610day/610analog.temp.gif

Also the GFS AO forecasts suggest that the AO will tank to standard deviations of normal,  > -5 by Mid Month.

See http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.mrf.gif

If you remember the 27th of December 1990, it was cold!

As a comment,

The up shot to all this is light to moderate snow within the next week…..then cold and a lot more cold the end of next week.

We have a couple of snow producing storms headed our way. One Sunday and Sunday night that will dump about a foot on the hill.  6 to 8 inches at the village for a Sunday night plow.

Additionally, A better snow producer with more wind is expected Thursday which will be the first of several more but drier storms that will deliver Arctic air into the great basin, later the 2nd half of next next week.

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

 

Saturday AM Update:

I keep seeing the same trend in the longer range this morning….Burrrrrrr!!!!!

RECAP:

1. It all began with the west warmer then normal in the Fall….then much wetter then normal in the late Fall.  Anomalous cold developed in December.  All this while the QBO was in its easterly phase with the 30 mb zonal wind index showing -20s in September and -20s in October then -18s in November and rapidly rising to -10 in December. The Quasi Biannual oscillation is represented by an index that shows both the strength of the winds at 30MB, (Stratosphere) from either east to west or west to east. It has been in its easterly phase now for well over a year and is expected to flip soon from from east to west to west to east.   From what I have read, the most dramatic effect upon the weather often time occurs during the time around the flip in direction. This is often associated with strong blocking over Greenland, IE a strong -NAO (a strong high pressure block over Greenland)  and a deep Hudson Bay Low. The combination of the timing of the flip which is beginning to occur now and will likely continue into February, and what the CPC is touting is leading me to believe that some serious Arctic air is going become entrenched over the CONUS later this month. It will mainly be from the Mid west then shift to the east!..For the folks that are missing the cold over the east, it appears that you are going to get yours big time, the second half of January. This Arctic Air may go deep into the south….. and the AGW crowd will be touting otherwise again!!

See: http://www.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20130104.NAsfcT.gif

Back out west……there is still the possibility that the first initial salvos of Arctic will begin in the far west with some of the thick soup breaking west of the Divide about mid month. The Cold will then shift east with time. If we do get a good shot of it and ridge over; as mentioned in a previous discussion, Bridgeport may go -25 to -30F.

Take a look at the following link. It is the latest forecast from the CPC for temps across the US.  The deviation from the standard is grossly off the chart!

 

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I took a trip to the Carson Valley, Nv via Bridgeport today. At 1:45pm it was 14 degrees downtown. That was probably about the high for the day after an early morning low of -18. A few days of that are tolerable I guess, but a week or more and I’d be ready for the head bangers ball! Lee Vining next to Mono Lake still socked in with ice fog at about 1:15pm today. I hope you folks get some relief this weekend as a splitting system tries to mix things up a bit. Some snow is expected for the High Country. However, mainly the Crest and south through the Southern Sierra. I would not be surprised if bishop picks up an inch or two of snow Sunday/ngt. Mammoth Mtn is expecting about 4 to 8 inches by Sunday night. Could be 3 to 6 inches in town.

 

What I have been seeing on and off for mid month January in the longer range concerns me. Especially since it has been so cold for so long in many areas. Not every model is showing this on a regular bases but the new 00z Saturday GFS has the eastern pacific ridge building north at about 145W to the north pole and tapping pure arctic and pulling it South over the far west and especially Great Basin. Temps over Montana at 18,000ft (500mb)  go south of -40C. This is just about our coldest weather type should it occur…..Especially in mid January. With so much snow cover over the interior far west and great basin, there will not likely be very much if any modification. Stay tuned…..as the mid month Yellow Knife clipper could be a real pipe buster!  If that occurs and we ridge up over the top of that air mass…Bridgeport could go -30f below.

Note this is not a forecast yet. However the trend is heading toward an Arctic Outbreak over the west by mid month or a little sooner. How far west the molasses gets is uncertain at this time.

 

PS>   The QBO is getting ready to flip from east to west to west to east. Looks like Next month will be the timing……

 

The Dweeber………………………:-)

Upper Ridge in the mean anchored over the Far West to keep a persistent Dry Cold pattern in place for California……Split Flow Pattern for the Rest of the Country….

Thursday Am Post:

Not as chilly yesterday with a strong inversion setting up. Highs popped to the upper 30s and low 40s while valleys continued in the deep freeze down into the teens and 20s.  In January when this occurs…the true “Banana Belt” within the Mammoth Eastern Sierra is about from 7800 Feet to Canyon Lodge….Usually not the Trails and absolutely not the Crowley Lake lower subdivisions, as they both are commonly below the inversion and thus colder!

The temperature inversion is expected to remain in place for another 48 hours then possibly weaken a bit over the weekend as today’s more progressive model solution in the eastern pacific takes a weakening short wave through the upper ridge Sunday into Early Monday. This may allow some snow showers or light snowfall for a time Sunday. Will update in this the next few day to see how and if it holds together.

Otherwise the next change in the pattern is expected occur about a week away next Thursday as the eastern pacific ridge retrogrades to about 140ish and a cold arctic air-mass invades the Midwest. Potentially…..This will bring some of the coldest weather to the Midwest in several years.  Typically this is still considered a drier than normal pattern for the Eastern Sierra. Some light snow is still possible. The return of wet weather to the Sierra is discussed in yesterdays discussion.

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Note:

Some clarification to yesterdays post at the end of the Longer range:

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Yes its chilly!…..The high was 30 at the Village yesterday, 9 degrees this AM. However, nothing compared to Bridgeport with lows again near -20F for the 3rd straight morning! This time of the year when the sun is at its lowest angle and you have snow cover in place as well as sinking air, it can get very cold. There is no real mechanism to flush out the cold until the weekend.

The weather pattern over the CONUS is split-flow.  The short waves coming toward the coast are being effected by the far western upper ridge. These systems are splitting with the northern branch the strongest, diving SE out of Canada, with then a weak southern branch coming out of northern Baja, Mx.

At the moment there is a REX Block over our state with a small upper low just off the northern Baja Coast near Ensenada. At the surface, a 1044mb high is located over SE, Oregon with light easterly flow at the surface from Nevada. By Friday the upper low to the south of us kicks east into New Mexico while we stay ridged up. Air Quality will slowly diminish especially Thursday into Friday and possibly through Saturday.

Since any significant snowfall is pretty much out of the question for a week, the interests will focus upon Air Quality for the Eastern Sierra as well as temps.

The Models:

1. 12z GFS has the next upstream system splitting with another southern branch short wave cutting off and effecting Southern Ca before it heads east.  We may get some easterly flow from that system.

2. 00z ECMWF has the system splitting further offshore with a more slower solution and more ridging for the Eastern Sierra.  This is probably the worst case for air quality and the strongest inversions.

3. 12Z GEM has the short wave more progressive as it comes through California with enough wind and UVM to flush out whatever….and even a dusting of snow. However, like most cases, the (GEM) Canadian model does a poor job for the west coast for some reason and is discounted.

The UKMET was initialized poorly showing an upper low over Northern Ca this morning. The models guidance was thrown out.

Longer range:

The GFS for the past 2 runs has been showing some retrogression and amplification for the Eastern Pacific Ridge.  It sets the stage for some serious Arctic Air to penetrate deep into the Mid west via Montana. No doubt that some of this “Thick Soup” will break west of the divide and so another shot of cold will likely flush through the Eastern Sierra between the 10th and the 15 inside “Gangnam Style”.

LONGEST RANGE THINKING:

The Dweebs checked the weekly CPC discussion on the MJO. It appears that the MJO is in phase 3 and is expected to remain weak to moderate as it progresses to phase 5. So, extra-tropical impacts of the MJO may become more prevalent over the next couple of weeks as the diabatic heating serves as source for downstream Rossby wave propagation.

The seeds for this interaction are seen in recent 200-mb zonal wind anomalies, which nearly match the canonical composites associated with phases 3 and 4.  The result is;  a retraction of the jet across Asia and positive height anomalies downstream south of the Aleutians. This could translate to positive height anomalies across eastern North America. The latest extended range forecast is in agreement with this scenario toward the middle of January.  Should the MJO bring enhanced convection into the Western Pacific and subsidence into the Indian Ocean, the opposite forcing would occur, with the MJO forcing an extension of the East Asian jet and a downstream pattern reversal over North America by the end of the month…..”Bringing wet weather back to the Sierra“.