Heavy Snowfall Returns to the Sierra with 1 to 2 feet expected……Snow showers will continue post frontal today and then unstable air could keep them going through the weekend…..Colder weather expected over the next 5 days…..
Thursday January 30, 2014
Posted at 11:53 am by Howard
WX front has moved through and scattered snow showers are now expected the remainder of the day. Next and last wave moves in later tonight with a period of moderate snow returning……
The Storm began pretty much as expected early this morning. Snowfall rates were enhanced by a couple of 850mb/250MB couplets over the North Central Sierra and the other associated with a surface low near Bishop, Ca. The couplets are areas of vertical motion enhancing the precipitation process.
At the moment the hose is pointed at us….but precipitation rates should taper off within the next few hours. More showery weather is expected this afternoon instead of the steady heavy snow that was occurring mid morning. It will also get colder as the day goes by as there is a lot of cold air behind the front. Currently, accumulations are about a foot at McCoy Station as reported by Cliff Mann of Mammoth Mtn. More will pile up during the day and especially later tonight.
We could easily see another 6 to 10 inches more by morning over the crest as there is another feature that will come through late tonight bringing another 3 to 6 inches or so by Friday AM. That Vort max will be coming through in colder air so it will be drier with higher snow to water ratios. That should produce more snow from the system with less water. Storm totals over the upper elevations will be between 15 and 24 inches by Friday AM. This has been revised upward about 6 inches from yesterdays discussion.
Mammoth remains on the cyclonic side of the upper jet that will be well to the south of Mammoth over the weekend. The following system that will affect Southern Ca will come though about Sunday night or Monday. The track is a little uncertain with the 12z ECMWF taking it a bit more east. Should that verify…Mammoth would benefit as we become under the influence of the deformation zone. The NE quad slips by late Sunday night or Monday AM. I will update in the morning to see if this is a new trend.
Otherwise, next week still looks pretty dry over all, but there are some interesting possibilities that weekend that I will be discussing next week…..
New 12Z Thursday ECMWF as pretty good storm breaking underneath blocking pattern over Bering Sea. the EC is very wet with this storm bringing in over 2+ inches of QPF late in the weekend while the GFS is clueless at the moment….
It is slick out there so…..Slow Down……Drive Carefully>>>>>>>>>>>>
While a Moderate Storm is brewing on the Horizon…Partly cloudy skies along with warmer daytime temps expected through mid week….
Sunday January 26, 2014
Posted at 10:21 am by Howard
Brief Tonopah surface low develops all snow for the Town of Mammoth after Midnight tonight. Thus amounts by Friday AM could be 6 to 9 inches with most of it by Thursday night…
Amounts on Mammoth Mountain should be in the 12 to 18 inch class between 9K and 11K by Friday AM. The storm will be followed by an unsettled period Friday and Saturday with little if any accumulation. We go dry for the following week…. High temps today will be in the 50s today then 30s Thursday.
Some pretty cold nights are ahead for us this weekend with teens…..
Dr Howard and the Dweebs………………………..:-)
forecast models developing pseudo Tonopah Low Thursday Morning and will have the effect of bringing the cold air in quicker. It is obvious the models are not handling the QPF or snowfall potential as well as they normally do.
Thus will beef of snowfall amounts for our town as well as upper elevations as colder air gets in here quicker with wet fetch and combine with much higher amounts than expected this morning…..
Up to 8 inches is now expected in the Village with a foot plus at the main lodge and 18 inches over the Mammoth Crest….
WSW now hoisted for Midnight Wednesday night..
Tuesday AM Update:
Just a couple of notes to mention that the system looks to be slowing down a bit. That is good news, as that will give the colder air a chance to get in here with more of the precipitation with it. To what degree is not known at this time.
CRFC has the Freezing level about 9700 ft at 4:00am Thursday with a snow level approx. 8200 feet. The freezing level falls to 8900 at 10:00am which equates to a snow level about between 7400 and 7900 with a tighter spread adjusted for more 700RH moisture. By 4:00pm Thursday, the freezing level is forecasted to be at 8300 with a snow level at 6800. By 10:00pm the freezing level should be at 6800 with a snow level at 5300, or down to the Mono County Valley floor.
The timing of the precipitation is critical in a system like this to determine the amount of snowfall in the towns of Mammoth and June. As you can see the snow is going to be pretty wet “early in the morning” Thursday at about the 8000 foot level. The best accumulations will occur early to mid afternoon for the Town.
Amounts in Town. EST. From 2 to 5 inches. A lot of this depends upon the timing of moisture and how fast it moves through. The very latest guidance is showing it moving through slower now…..and so we could very well get more snow in town if the band remains in our vicinity well into the evening.
The Crest may get a foot….again this is subject to change depending upon how fast or slow the band moves through. Timing is everything…..
Expect an update again Wednesday AM as the Dweebs have another day to look at it.
The Weekend looks cold with the chance of some snow showers…..highs in the 30s lows in the teens
Beyond this storm there is a secondary short wave that will approach the coast Sunday night. The new 12Z GFS has the systems trajectory on a path to the South Central Coast then SE which would benefit the Tehachapi Range and Southern California. I do not expect much more then some light snow showers from this system at most, early next week. However, the Owens Valley may benefit…especially the Southern Half.
As mentioned over the past few days…The warm weather of the past few weeks will be over Thursday. At least for quite awhile. I see a predominant NW flow aloft similar to the weather last December. With the eastern pacific high parked further west. (retrogression) So we will becoming colder then normal with time and there will tend to be systems that become cut off or closed off over the great basin. With a little luck we may end of getting one of those famous Tonopah Lows that gets stuck, providing upslope for days. Although that is not in the forecast, I see the possibility of a potential pattern like that occurring later in February. Especially how blocky it has been over the far west.
The Tonopah Low
What needs to happen:
1. A stronger than normal high pressure system off the California coast, along with ridging over the Pacific Northwest.
The resultant flow advects cold air from the interior of Canada into the warmer air mass over the Great Basin. This unstable situation is intensified by one of the following mechanisms:
(a) A wave on a west-east oriented front.
(b) A secondary low in an unstable air mass that follows the passage of a frontal low.
(c) Beneath a cut-off low, or at the tip of a long wave trough, which has a jet maximum over the area.
Some hint of this pattern is suggested the following weekend………………
Quick Update Monday:
Here are the bullet points
1. This is for the most part a 24 hour storm.
a. Thursday Morning through Friday Morning.
2. It will begin warm with the freezing level at 10,000 feet late Wednesday Night
a. Main event for Mammoth is between 4:00am Thursday and 4:00pm Thursday
b. The Freezing level at 4:00 am over Mammoth will be 9500 feet. By 10:00am it drops to 8500. and by 4:00pm 7,000.
These are the freezing levels. The snow level is usually between 1,000 and 1500 feet lower.
So by 10:00am the snow level could be a high as 7500 or as low as 7000 feet. Snow to water ratios will be low.
Based upon the QPF we will be lucky to get a foot of cement at 10,000 feet However sierra cement is more important that
any kind of snow we could hope for!
Post stormy weather will be showery with little additional accumulations….possibly a few inches Friday and Saturday. The system following this one will be too far off shore when it heads south down the coast to be if benefit. Southern-California may get some of that.
Fantasy charts show the end of the warm weather as we have known it by Thursday. However, with the upper mid latitude ridge now forecasted to be out about 130 to 140 west….. NW sliders will keep mostly seasonal temps and windy weather more often than not, over the higher elevations next week.
Longest range has next significant storm about the 9th.
Happy Ground Hogs Day Sunday. Good chance he sees his shadow…..
Dr Howard and the Dweebs…………………:-)
es…the Dweebs did say snow. That was not a mistake….
Best guess at the moment….12 to 18 inches over the Crest between Thursday and Sunday
This looks to be a storm in-between dry patterns. The previous and current pattern was/is warm and dry the next one setting up for week two look cold and dry. In between patterns is a storm that is going to sneak through.
Here is what’s happening.
Powerhouse storm in the central pacific with an earlier 180Knott upper jet was responsible for huge waves this past week along the Ca coast. By the time that storm gets into California later Thursday and Friday, it will be but a mere fraction of its former strength. Why?? You guessed it.. It runs into wall of high pressure. The upper ridge that has been with us all January is taking its toll on that storm. However all is not lost. The Storm will be responsible for splitting the upper ridge into two parts. One that will remain over Southern Ca Wednesday and the other that gets pushed up over Alaska at the same time. So what we have a sort of a weak break through of the westerlies underneath that AK block and the remaining part of the upper high over Southern Ca. That southern portion gets suppressed to the south in response to the approaching and may I add weakening wave. There is another wave that will follows Saturday afternoon from the NNW bringing snow showers.
This all gets accomplished by the fact that the Hudson Bay low shifts east enough for the wave length to extend enough east for this to happen. The main point I want to make is what happens after the weekend. What happens after words is that the AK block redevelops west (retrogression) and a -WPO develops near the date line. This in turn pumps up an eastern pacific ridge further west of where it has been. So the pattern change is associated with significant retrogression and the models are struggling on where to place the Eastern Pacific Ridge…..which will have profound effects to CA weather.
Dr Howard and the Dweebs……………………….:-)
Another dry week ahead is expected for California while week two models still beat with the promise of some snowfall during the 1st week of February…..
Thursday January 23, 2014
Posted at 9:19 am by Howard
Storm for later next week still looks good….a foot plus up on the hill…..GFS has it starting earlier like Thursday….ECMWF is wetter with about 1.5 inches of water EQ.
Stay tuned…will update daily…………..
That’s it! I have heard this silver bullet story again today….The media is quoting some climatologist saying that the warm water pool in the Gulf of AK is causing the drought. If I hear this one more time I am going to be ill!
I do not believe in the -PDO and Warm water pool Gulf of AK drought connection and neither should you! It is another knee jerk, silver bullet answer for a system or structure that is wagging the dog from much further away then a few thousand miles.
If Air Sea coupling was really working in the Eastern Pacific, we would not continue to have the kind of weather that we have In January. It would Cold and drier than normal not warm and drier than normal.
1. Warm Water SEE: http://weather.unisys.com/surface/sst_anom.gif
This warm water pool near 150W and 42 north is usually there! It is usually found between 160W and 150W. If it was really coupling, the upper high would be just to the east of it and a long wave trof would be over the far west. IE (30 degrees east of the anomaly) The -PDO which in this neck of the woods equates to a colder N/S west coast current, has weakened recently. Colder SSTA supports trofing not ridging aloft. So in effect, if that was driving the pattern, it would be cold over the far west and showery! Is it cold and showery? California has been setting high temperature records for the past two weeks!
Air sea coupling is important, However,
1. Did this guy realize that the MJO in phase 6 often teleconnects to ridging in the NE pacific? How about the fact that this is a La Nada year with little if any support to southern stream enhancement! That the QBO in its positive phase is much more convincing for west coast dryness in La Nada years then the -PDO/Warm Gulf of AK connection.
Take a deep breath!!!!!!!
The most exciting news out there is that significant Kelvin Wave action is taking place that may have greater benefits toward the development of a significant El Nino for Next Fall/Winter……
Check this out and then check you pulse!
Now that’s what I’m talking about!
A storm is still on track beginning early Friday AM next week. This looks like the potential to be a moderate precip producer. This means that it could dump a foot between Friday Am and Saturday AM on Mammoth Mtn Although this is a wag at this time….. I will update; weighing in each day now on the progress of the pattern change into next week. As far as the pattern goes, it will be in transition (retrogression day+8 thru day+11) …….eventually turning much colder week 2. (Post super bowel)
Fair and dry with high cloudiness on and off the next few days…. Highs in the 40s today then 50s next week up until Wednesday. Winds will increase Thursday and Thursday night with a Chance of snow developing by Friday. This will be a cold storm, so expect snow and not rain.
At this time I do not see a major change to a wet pattern for California.
Dr Howard and the Dweebs………………..:-)
Friday PM: 5:45PM
The pattern changes are beginning to get into the later part of the week one period and it still appears that we’ll get some light snowfall next weekend. Like between the 31st and the 3rd. Is this finally the end of the drought pattern? I say no…..Just a break for the time being… However, this break may allow some important snow to fall later next week.
Looking at the MJO it is strongly in phase 6 with no sign of moving. To me that locks in the north East Pacific Ridge with down stream effects of more arctic shots…however, as time goes on these shots will drop into the US further and further west as retrogression of the eastern pacific ridge takes place. I am not sure how far west the ridge retrogrades but it may get west enough for some pretty cold weather out west later week two.
From the CPC::
Persistent convection near the Eastern Maritime Continent and parts of the West Pacific could have important impacts on the extratropics from the North Pacific downstream into North America. In recent observations, an extension of the East Asian jet stream has been observed, consistent with convective forcing from the West Pacific over the past week to ten days. Therefore, the forecast pattern of tropical convection favors continued ridging in the Northeast Pacific over the next few weeks.
So far the southern stream is still very weak over the eastern pacific. This is probably due to La Nada. A strong southern stream would break loose the westerlies into CA if we had a moderate El Nino. So this is unlikely to happen.
Friday AM Update:
The weak upper low that back doored us yesterday is now off shore and moving north while some high level subtropical moisture was pulled up in its wake. They are just high clouds for the most part and will not produce precipitation. The clouds should thin out during the day as the upper circulation off-shore, pulls north.
Highs today will be in the mid 40s with lows at night in the single digits, teens and twenties depending upon your elevation. The coldest temps will be in the valleys like Bridgeport. Warmer days with clear sky’s will return Saturday and the trend of warming continuing through the middle of next week. Expect daytime highs about 60 by Wednesday and again Thursday.
It is what happens after Thursday, what is on the minds of most, as we finish the end of the month and begin the next. The longer range models are all about building the upper high to some extent NW toward Alaska with both retrogression and a weakening of the heights in the mean along the west coast. This leads to the possibility of a westerly break through of energy for the central west coast between the 31st and the 2nd. ( IE Super Bowl Weekend)
The Dweebs should have a better handle on it by next Tuesday or Wednesday.
Of Note…At this time there is no forecast confidence of how much precipitation we will get at this time…..
While near record high temperatures occurred in the Owens Valley this week and short-term models spend their time determining how much warming or cooling is expected each and every day going forward, a pattern of transition is expected the end of the month into the first week of February. The Dweebs have been reluctant to stick their necks out and say that the change will bring snowfall. However, I think that it is not unreasonable to believe that before the end of that 1st week of February, that at least some snowfall will bless our area with light to possibly moderate amounts.
Expect high cloudiness today due to a small weather system back dooring the sierra as it moves east to west off shore. The system will head up the coast toward Canada Friday. Some light snow showers or flurries may occur tonight. It will be about 10 degrees cooler today and slightly warmer tomorrow. Expect strong inversions to return by the end of the weekend. Some gusty winds will likely continue over the upper elevations the next few days.
In case you have not noticed…the days are getting longer and the sun is in return to equinox. For this winter, this is not a bad thought as I have hopes that the current pattern that is entrenched, will get broken up by an increasing amount of differential heating as the North American continent slowly begins to warm in February. Breaking the legs of drought structure is a concept that is simple in thought. However, every month has its own climatology and is effected differently by the variables of Air/Sea/Solar/tropical convection/snow cover and the upper level wind systems that come together for a single days weather.
The weekend will be a fair one, with highs in the upper 40s for the most part ,then low to mid 50s by mid-week. Nights will be in the upper teens tonight…then moderate back into the 20s this weekend.
By next week toward the Super Bowl weekend we should have much better visibility from a weather perspective on how this new pattern will affect California Weather. Will it dumps for days?….or will we just get wind and light snow……Stay tuned….
Although the next Sunday is Super Sunday…..out in the west The Ground Hog will take center stage…after all, is he not the greatest prognosticator?
Dr Howard and the Dweebs……………………….:-)