Archive for February, 2014

Wet Pattern to continue today then mostly end after midnight tonight…..Snow Level will fall to 7000 feet by midnight tonight….With an Anticipated 2 to 3 feet of Fresh Snow over the Higher Terrain….Mammoth Mountain will Expand its Skiing and Boarding to other Available Terrain…..

Sunday PM:

This is last update on this storm.  The main thrust of the last wave is moving into the high country with increasing precip rates. Mammoth Lakes may pick up another .5 to .75 hundreds before the nights over.  All with be snow on the mountain and turning to snow in town where some 2 to 5 inches is possible by morning. Monday morning may still experience some lingering showers early, with improving weather during the afternoon. The storm door closes thereafter until late in the week when the weather may become unsettled….the main track still remains to the north.

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There is a lull in the precipitation rates this morning…..The temperatures at 8:19AM at the 8200 was 37 degrees. Latest satellite motion shows the AR band of moisture thinning. However there is some enhancement out about 140W which is probably the wave that will end the storm for the Sierra and lower snow levels later tonight. By the time the snow level lowers into the town, most of the moisture will be through. However, the town may still get some 2 to 4 inches of accumulation before it is all over.  The vast majority of this storms precipitation has been and will continue to be from about Sonora Pass northward.  The Mammoth Pass storm total thus far is 1.6 inches, Yosemite 2.22 and to our neighbors to our north, Blue Canyon at 9.33 inches.

There looks to be about another 1.00 to 1.50 of precip to fall today and tonight. Thus….It is possible that another 10 to 15 inches of snow could fall at elevations between 9000 and 11,000 feet, temperatures considered. ( IE the ratios will be higher later tonight)

The Snow level will remain little changed in the Mammoth area at about 8200 to 8500 feet until later this afternoon when in comes down briefly to 8000, then rises back up to 8200. After 10:00pm, it will gradually fall again to 7000-7500 feet.

By Tuesday of next week, the freezing level takes a hike to over 11,000 feet.  It looks to be a 6 to 10 day period of above normal temps and below normal precip. However, Mammoth Mountain will have picked up a good 2 to 3 of feet of dense snow that will greatly expand the terrain available to skiers and boarders for the upcoming presidents holiday period. Once our air mass dries out, night-time temps will cool back into the 20s and the snow will tend to dry out a bit as well

Long Range:

As the Dweebs have mentioned several times before, as the sun get higher in the sky later in the month of February and into March, chances are good that parts of the complex structure of variables that have created this winter will begin to break down. It will then be toward months end and well into March that the Snows along with colder temperatures will return to the Mammoth Lakes high country as long wave trofing over the eastern pacific returns by next month.

“AR” still headed for Northern California…..Mammoth could get 3 to 4 inches of Water up on the Pass…..Saturday and Sunday….

Sat 9:50pm

Mammoth Pass reports 1.22 inches of precipitation so far and less than Yosemite. Temperature at 8200ft is 36 degrees, while at the main lodge it is 30. Snow level about 8400.   Main Plume is nearing the north coast now and will be moving in shortly over the north coast. Precip rates will pick up after midnight tonight with another inch and a half of QPF expected. Snow levels are verifying a little lower than forecast…..so it is now possible that some 3 to 5 inches may fall over the next 24 hours at elevations above 8000 feet by Sunday Afternoon.

After this storm…. the storm door closes except for a few minor systems.  Both 6 to 10 and 8 to 14 outlooks look drier then normal….

 

Next update in the morning……

 

Saturday AM Update:

At 9:30am this morning, the FMCW (Snow Band Snow level Radar) at the Pine Flat Dam located 36.83N and 119. 31W is pretty representative of the snow level over the Mammoth Lakes Location to the west of us. With a prevailing westerly flow it showed the Snow level at 8524ft at 3:30AM this morning and at 9:30Am at the 6976Ft. So the snow level has dipped for some reason.  However, although there may be micro physical processes at work here, the results still show the snow level rising tonight into Sunday AM. The freezing level is expected to remain at or above 9000  and that the last wave comes through Sunday night. At that time there would be the chance of snowfall accumulations in town. How much depends upon how quickly the snow levels drops and how much moisture is left in the system at that time.

The New CRFC update at 2026Z shows the Freezing level at 8500 at 4:00am then 8800 at 10:00am over Yosemite. At Huntington Lake it was 8600 and 9100 respectively.  However at 4:00pm and 10:00pm at Yosemite, it goes up to 9100 and 9400 and at Huntington Lake goes to 9300 and 9900 respectively. So it will get warmer going into tonight.  Remember the Snow level in saturated air is lower equal to or a bit lower than the freezing level but not all that much. Maybe 500 feet or so.

On another subject, the new model runs are not quite as wet at last night runs. If you look at the latest Sat imagery, the tropical connection is not as dense as it was yesterday. However, that is a stream of moisture out of the tropics that is in constant flux.

Longer range:

1. Highly amplified pattern over the central pacific will de-amplify over the next week. At the same time the big cold low now coming south north of Kauai and south of the Aleutians will eject through the west coast late next week. It will weaken as it moves through the eastern pacific and its trajectory at this time is mostly north of us.

 

More Later today….

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Nothing much to add from the last post other than it looks a bit wetter this morning for Mammoth. The QPF blend of models suggest 3 to 4 inches of water up on the pass. With orographic’s you can never get it exactly right and so it may end up more, so the 3 to 4 inches is probably a bit conservative.  This means that considering the freezing levels and the low snow to water ratio’s, the upper mountain should be in for a good 2 to 3 feet by Monday AM. In town the most snow will fall Saturday morning and it could be 5 to 6 inches before the freezing levels go to 9000 that afternoon and 9500 Saturday night. The snow level will be about 8000 Saturday afternoon and 8500 Saturday night into Sunday afternoon. It comes down later Sunday night and so will the snow level.  Strong winds will accompany the storm with gusts in town Saturday morning in the 50 to 60 range.

 

For those that plow, you may be busier in the elevations above the village longer Saturday before it too changes to rain, or Rain Snow mix

Let me know if you smell the pineapple’s……:-)

 

Here is some great news!!!

Scripp’s Institute just came out on February 3rd, 2014,  with their ENSO outlook for the next winter, ( The winter of 14-15). They are forecasting a major EL Nino. This is usually associated with big time snows for the Eastern Sierra, Tahoe South.

SEE: http://meteora.ucsd.edu/~pierce/elnino/fcst_gifs/fcst_made_2014-02_for_2014-12.jpg

 

The Dweeber………………:-)

 

Another Cold System will move through Thursday and Friday with warm advection pattern developing over the weekend…..Thus freezing levels on the rise over the weekend….

12:30PM Update:

Just took a look at the; NCEP Rapid Refresh (RAP) initial 2-06-2014 1900Z

Between that rapid update model and the valley radar it is evident that everything behind the front this morning has gone south and is now lighting up over the southern sierra. The upper jet probably remained too far off shore for any meaning full spill over. With the upper jet moving south, off shore, were out of the effects of this system for the most part except for a few showers now.

Warm air advection will begin to make its way into the Central Sierra later in the day Friday with snow levels low enough for light snow in Mammoth. Thereafter, the main hose moves into the northern sierra, spreading precipitation south by means of orographic and isentropic lift ahead of the warm front. QPF amounts in the models are usually under done and indicate only about 1.5 inches for Mammoth, which probably needs to be doubled for our area.  So 3.00 of liquid is the state of the art at the moment with a lot of heavy snow still expected for elevations above 9,000 feet Saturday through Sunday night.  Unfortunately for those in the snow removal business, with the snow level expect to rise to 8000 feet Saturday and 8500 Saturday night, there is not going to be much to push around. Snow levels will range between 8000 and 8500 hundred feet into Sunday afternoon. In fact the timing of the warmest air is Saturday night and so there may not be enough diurnal cooling for the rain to change back to snow that night. You will have to wait until the last piece of energy comes through Sunday night for the rain or rain snow mix to return to snow.  That may begin to occur as early as Sunday mid to late afternoon and should be all snow in town Sunday night for a good plow!

The weather begins to turn showery very early Monday AM….then we clear out during the day Monday and probably earlier than later.

 

Mammoth Mountain should still see “at least” two feet of base building snow this weekend and hopefully more…..

 

The Dweeber………………..:-)

 

PS:  Here are some tabulations from my good friend Bob Sollima who is a hobbyist hydrographier here for Mammoth Pass. I really appreciate him sending me records from time to time.  As you can see from his data,  we are doing than some of the driest years already. The precip that is coming this weekend will help as well.

Feb. survey: 2014 = 8.5 in. H2O (currently at 22% of full winter precip ave.)

1977 = 4.3 in. H2O ….end of winter result = 20.5% of average

1991 = 4.7 in. H2O ….end of winter result = 67.4% of average

1987 = 7.3 in. H2O ….end of winter result = 51.0% of average

2012 = 8.7 in. H2O ….end of winter result = 48.3% of average

2007 = 8.8 in. H2O ….end of winter result = 41.9% of average

1976 =10.1in. H2O ….end of winter result = 44.8% of average

1948 =10.2in. H2O ….end of winter result = 60.2% of average

1994 =10.3in. H2O ….end of winter result = 57.2% of average

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Thursday 11:40AM update…

 

Brief update to indicate that snowfall from the front has already moved through leaving 4 to 5 inches up on Mammoth Mt. earlier this AM.  Any snowfalls that occurs for the rest of the day should be isolated with further accumulations less than an inch… The action is currently both to the south of us and to the north of us up in the Northern Sierra. More later as to the reason….

 

1200PM Update:

 

Jus took a look at the “RUC” Rapid Update

 

The Dweeber….

 

Thursday AM Update:

Although it does not look quite as wet as it did yesterday, the QPF and moisture plume for the 5 day period is in the 2.00 to 3.50 inch range for the Mammoth Area between the town and the Sierra Crest. The Dweebs are expecting that over the upper elevations, there could be initially some dry powder then some heavy wet snow, with totals in the 2 to 3 foot range above 9000 feet by Monday AM.

Remember, that the snow to water rations are expected to be reduced significantly as we go in time from Saturday into Sunday. Then afterword’s…..The 12z Thursday GFS guidance for Sunday during the late afternoon and night look pretty interesting this morning as the main forcing (+PVA) with the upper jet is progged to come though at about (06Z Monday )10:00pm Sunday night. Thus some heavy snowfall is very possible for the Town of Mammoth and over the crest Sunday evening if that is correct. Precipitation should be ending during the late morning hours Monday with the upper jet redeveloping back to the north Monday night into Tuesday. There is another system that we will have to keep our eye on for Wednesday.

Snow levels will be problematic in town with the precipitation all snow in town through Friday, then afterwards the snow level going up above 8000 feet later Saturday and remaining above 8000 through mid Sunday afternoon.

So all in all, this is not what I would consider to be a drought buster storm for Mammoth. However, snowfall wise we could certainly see a few feet of snow over the highest elevations and the fact that the moisture content will be overall high is great news for those concerned about water,

QPF in this kind of pattern will change daily until we are within 24 hours of the event. This is true as well for the snow level forecast……So stay tuned and the Dweebs will do their best to keep an accurate WX picture without the hype.

 

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

 

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Lots of chatter now around town about the upcoming series of storms.  I want to put it all into perspective…

Storm number one is still a cold storm. It is getting a little moisture from the Hawaiian tap well to the WSW but the air mass that it is mixing with is cold, so expect Snowfall to water rations of possibly 15:1.  The QPF from California Rivers Forecast center is showing about 7 tenths so a foot still looks go over the upper elevations and hopefully a little more.  The town could see 4 to 6 inches and a bit more above the village.

Storm #2 as per the last discussion below is still looking wetter.  But for those that are seeing all the red-painted upon the graphics, be advised that we really do not know where the freezing level is going to be. CRFC is taking the level up to about 10,000 by Sunday.   In a saturated air mass, there is little difference between the snow level and the freezing level, so you can not count on the usual 1,000 to 1500 foot under the freezing level rule. However, there are microphysical processes that will allow snow to fall from the dendritic crystal growth zone to the surface at 8000 with the Freezing level at 10K so it might be snow or it might be rain. Well have to wait another day or two find out. Either way this is not what I would consider a major precipitation event for Mammoth but it may be the biggest storm of the winter so far.

The new 12z ECMWF paints about 4 inches over Mammoth Lakes, for the 5 day period including storm #1. So at this time we will benefit from the AR connection but not like Tahoe north where amounts of up to 9 inches are indicated mover the Sierra adjacent to Susanville.

The PWAT is impressive at 1.25 to 1.5, and with 5 day amounts approaching 10 inches of water, qualifies as a strong AR event. As a comparison, the upcoming event is nothing like some of the past excessive events that painted over 25 inches for a 5 day period, in years past.

 

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Wednesday AM Update:

The guidance has changed over the past 24 hours and has trended wetter for our area for both systems. One result of the change is that it will not get nearly as cold. Additionally, with less amplification upstream, pacific air will become more dominant over time Friday and into the weekend as the pattern actually becomes more Zonal. This is really a change over the short to medium term.

1.  Model guidance has shown a significant change over the past few days in less amplification of the off shore eastern pacific ridge, and thus much less deepening with the modified arctic air over the northwest into the far west. Much of this cold air mass in the pacific north-west will now become more stretched out east-west with the bulk of it heading east. The western portion will assist cyclogeneses as the upper flow becomes confluent with the upper jets off shore. As the upper flow becomes rapidly west to east Thursday, the first system takes a more southerly track as heights are pretty low at that point in time. That main target is the southern and central sierra including Mammoth Lakes. I would not be surprised if the town got 6+ inches by Friday AM and the upper elevation well over a foot as snow to water ration’s will be pretty high.

2. The second system is also trending wetter.  In fact this is an atmospheric river related system that now has impressive precipitable water amounts forecasted to 2 inches. The trajectory is from the Hawaiian islands and although the main focus is still Northern California, is has trended a bit south of late.

Any further shift south by Saturday could result in heavier precip amounts for our local sierra over the upper elevations in the 1 to 2 inches (or more) range. At a 10:1 ratio, that could be an additional 10 to 20+ inches above 10K. The freezing level will rise close to 10,000 feet by Sunday. So what ever snow falls in town Saturday, will become pretty mushy by Sunday.

 

Stay tuned……..I will update either later today or again in the AM…….

 

Dr Howard and the Dweebs…………………:-)

 

 

I have looked at the all the guidance this morning and the west coast ridge is still doing the same thing. That is,  moving back and forth between 140West and 120west. So either its going to be colder than normal and drier than normal or, warmer than normal and drier then normal. In either situation and in between we can get light or occasionally a moderate shots of precipitation. However, you’re not going to get to the pattern that we want along the west coast without a shift in the high latitude block in the -WPO position eastward to the -EPO.

The MJO has been locked in 6/7 and it keeps circulating the same like a skipping record.  If this were a moderately strong Enso year the subtropical jet would have swept the legs out from under the current west coast pattern.

Now a new Climatologist claims that “it is” the negative phase of the PDO with the addition of the neutral ENSO conditions for the excessive west coast dryness. The claim is that during the negative phase of the PDO and with its protracted cycle in time, drought over the west are more common because of the effect of weaker and far fewer warm phase El Nino Events.  Possibly……there is certainly more logic in that statement as compared to others lately. One comment about the weather in the east this winter, is that this years winter has proven that the AO and NAO in the positive phase can certainly produce very cold winters without those oscillations being in their deep negative phase for long periods of time.  Which is more of a concern to long-range forecasters I think.

WX discussion:

OK….here we go again….

With the eastern pacific ridge out about 135 to 140west, another system will makes its way into the pacific NW over the next few days allowing another shot of very cold air to advect into the Great Basin. There will be an increase of wind over the crest Wednesday into Thursday as the heights fall north to south instead of the preferable west to east. The upper Jet is going to spin up to the south of us, pulling in a little pacific air and moisture for some light snowfall Thursday and into the night. (2 to 5 inches). Then as the system shifts east Friday, the upper jet will lift north through us into the Pacific Northwest over the weekend and become anti cyclonically curved. Thereafter, the upper ridge axis sets up over or just off the CA coast for an extended period.  Meanwhile over the weekend, the hose appears to be pointed at Northern CA and eventually the pacific northwest. So again we get the southern remains of the moisture fetch with higher snow levels over the weekend and early next week.

Looking at the climate models, they still insist upon a significant wet period, for the northern and central sierra in their 45 day outlooks. However, either they are totally wrong,  or they are too fast,  as I see nothing in the ensemble’s suggesting that this far south.

Yes….with an anti cyclonically curved jet as by buddy Tom C points out, you can get significant precipitation with heights between 576DM and 570DM. However, I have not seen any sign of any sustained robust upper subtropical jet anywhere near this latitude/longitude to suggest that is going to happen yet, except possibly this Sunday for a time. We might get a moderate shot of precipitation from the Hose to the north of us. Otherwise, we wait and wait for later in February and March, while hoping our water storage will be blessed with more water….

 

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