Storm total 12 to 14 inches……Very Light upslope today is not expected to add much the next 36 hours as upper cut off gets the Boot ENE….More Snow Possible for Thanksgiving….
Friday November 22, 2013
Posted at 9:21 am by Howard
Saturday AM Update:
This will be brief…
The Upper Cut-Off has kicked inland along the Baja/CA border and is moving quickly into AZ. Cloudiness will be quicker to more out today and tonight. Fair weather is expected Sunday through Tuesday with a slow warm up. Next system will not be anything to write home about. It will weaken rapidly as it approaches the Southern CA coast line. According to the EC most of the precip will be confined to the coastal sections of LA…..Not the MTNs. However before it approaches the south land, some light snowfall may occur over the Southern Sierra Thanksgiving. Mammoth MT looks to receive a glancing blow from this system with a few inches possible of snow possible.
More Later….and sooner if this changes….
The pattern is winding down and it looks like Mammoth Mtn will end up with 12 to 14 inches over all. We got a few inches in town yesterday as the upper flow veered from the SSW to SSE to East to NE. Light up slope brought upwards to two inches the past 12 hours….. Currently the upper low is located off the coast of San Diego. The system is quite dynamic and is entraining a lot of moisture off the coast of Baja and pulling it over the deserts of SE CA and up through Nevada and AZ then west ward over the Southern Sierra. Mammoth is pretty much on the northern edge of the moisture field. However, some may surge a bit north again when the system lifts out Saturday. So either some light snow, or flurries will continue the next 24 to 36 hours. No significant accumulations is expected through the period.
Looking at this mornings 12z NAM at the Surface, there is a double-barreled strong surface high, one that’s 1048MB, located just east of Northern Canadian Rockies with pure Arctic Air just beyond the ribbon with Thicknesses down to 498DM and another center of 1046mb over SW Montana. The surface Gradient is toward the Cut Off…off San Diego and a bit east to its Surface Low. The tightest gradient is between Northern and Western Nevada and the Southern Owens Valley. So expect North Winds to really increase today over Eastern CA including the upper elevations of the Sierra, Western Nevada and the Owens Valley. The good news is that Mammoth Lakes is very protected from north winds because of the topography. Rarely are they any stronger than 20 to 35 MPH.
Expect a slow decrease in the winds later tonight and with the surface highs pushing ESE in general, Saturday will be breezy over the upper elevations but not nearly as windy as they will get today. Upper Elevations are considered mainly above 9,000 and the top 11,053.
Outlook is supported by all models in spreading some dry eastern pacific air over the region late Sunday night into Tuesday. This will be followed by a small storm, late Wednesday Night into Thanksgiving. That storm looks to bring the best chances of precip to the coastal sections of Central and Southern CA….inland to the most Southern Sierra South. The main concerns with this system at the moment is that it will remain too far off shore for much of the CA. The New 12Z GFS deterministic run is more progressive than last nights 12Z ECMWF. If the EC jumps on the wagon over the next few day taking the system a bit closer to the coast…..confidence will increase. However…..the big message here is that this is not a big storm by the looks of things…………..
Best preliminary estimates…..and I have to admit that this is probably on the high side, 2 to 4 inches in town and 4 to 8 over the upper elevations by Thanksgiving…..This precip forecast is early in the game and will change over the next few days either way but the bias is to lessen it……… In that the Dweebs are seeing a more progressive solution in the new 12Z GFS Run being a bit more progressive solution at this time, that is why the amounts are stated as it is in the guidance.
But as Dweebs know….Guidance is not really a forecast……it is just guidance……the Art is in the hands of the Chief……
Dr Howard and the Dweebs……………………….:-)
Thursday November 21, 2013
Posted at 9:08 am by Howard
Thursday AM Update:
Storm total as of this morning as reported by Mammoth Mountain was 7 to 11 inches….pretty much in line with what the Dweebs forecasted….which was 5 to 10 inches then increased to 8 to 12 inches yesterday AM.
We still may squeeze out another 2 to 4 inches from the next system as the flow at 700mh switches and becomes NE. This is the last in the series of short wave energy with this particular Trof. This last bit of energy has already formed a closed circulation at 700MB over Central CA. The upper low will become cut off top to bottom today as it spins up into a cut off low. So an upslope pattern will develop today in the cold air. The Dweebs note that the new 12z NAM shows 700RH blowing up this afternoon over the eastern slopes between mid afternoon and this evening. No doubt there will be at least a few more inches of snowfall here and there. The Dweebs are expecting another 2 to 4 inches by late tonight. The bulk for the precip from this system will be to the south of us with areas of the Owens Valley and Southern Sierra getting quite a bit of precip south of Olancha.
Looking Down the Road:
A fair weather ridge of high pressure aloft will build in Sunday into Monday keeping the weather fair Sunday through Tuesday. The next upstream system is associated with a weather pattern with blocking in the Gulf of AK and a subtropical ridge upstream east of the Hawaiian islands. The upper height anomalies are out of phase for a deep full latitude long wave. Thus with the next system for the middle of next week (The turkey system) No pun in tended, is currently being handled with uncertainty in mind. Last nights deterministic EC closed off the system, far enough off shore that the main area of precipitation remained off shore. This is not a progressive solution. However, if you look at the ECMWF ensemble members, they are more progressive and the GFS has been and is still progressive. So The Dweebs for the time being are into the new 12z GFS solution giving us the possibility of more snowfall Later Wednesday into Turkey Day. This is a decent storm with the possibility of a foot or better. Again, we are 6 days away from next Wednesday and things can change. This is an outlook not a forecast…… Will check and see what the new 12Z Thursday ECMWF has in it this afternoon when it comes out.
Dr Howard and the Dweebs………………………………..:-)
Mammoth Mountain Reports 4 to 6 inches of fresh snowfall overnight…..another 4 to 6 inches likely by Thursday…….Main portion of storm to move in late today……Snowfall expected Tonight into Thursday morning then showery weather into Thursday Night with Upslope Snowfall…..
Wednesday November 20, 2013
Posted at 9:04 am by Howard
Thursday AM Update:
Storm total as reported by mammoth Mountain is 7 to 11 inches….pretty much in line with what the Dweebs forecasted….which was 5 to 10 inches then increased to 8 to 12 yesterday AM.
We still may squeeze out another 1 to 3 inches from the next system as the flow at 700mh switches and becomes NE. This is the last in the series of short wave energy with this one coming down and spinning up into a cut off low. So a upslope pattern will develop today in the cold air. The Dweebs note that 700RH blows up this afternoon over the eastern slopes between mid afternoon and this evening. No doubt there will be a few more inches of snowfall here and there. the Dweebs are expecting another 1 to 3 inches by late tonight. The bulk for the precip from this system will be to the south of us with areas of the Owens Valley and Southern Sierra getting quite a bit of precip south of Olancha.
12:30pm Update: Longer Range
Longer Range 12Z Wednesday ECMWF model still has storm system moving toward the South Central West Coast. Looks to be a potentially good precip producer for Mono County Southward beginning Wednesday afternoon the 27th into Thursday. There after system may tap into good moisture pool for significant rains for SC. More later……..
An impressive 4 to 6 inches of snowfall occurred on Mammoth Mountain last night. Not from the stand point that 4 to 6 inches is a lot to fall on Old Woolly, but in that it was mostly orographically induced. Mammoth Weather.com picked up only .05 hundreds……so a lot of Topo Lift was occurring last night to get that much snow! In that the main dynamics is still yet to come, we could reasonably see another 4 to 6 by Thursday, as the meat of the lift comes in later today into tonight. Colder air following moving into the area later today and tonight is a plus for the snow pushers in town. Nice to see a baroclinic leaf forming in back of the wave off the coast of SFO at 8:45am, Wish we could get some of that! Maybe we will late this afternoon. I will have another update later today as the rest of the new guidance comes in. PS Mono Wind event possible for West Side of the Sierra this weekend….Not to worry for Mammoth just a Chilly breezy weekend
Longer Range: Development of Mid Latitude upper low with eventual subtropical fetch for the offering……
This may morph into quite the wet system for Southern California between Thanksgiving and the end of that week……
ECMWF has areas of 2.00 inches that following weekend….