Between 4 and 5 feet reported on Mammoth Mt with a couple of feet in town….The next system rolls in later tonight with more sunshine expected by late Monday AM into the afternoon…..Snow showers expected Monday PM…..
Sunday March 6, 2016
Posted at 10:17 am by Howard
Upper jet diving south toward Baja this morning as upper low slows and slides SE. The Dweebs have seen this scenario before. Essentially, this storm will not come through the sierra. Rather…it digs south into BAJA, Mexico. Coastal sections of California will likely get the lions share of precipitation while east of the Sierra into NV only light amounts. I suspect that the Winter Storm warning will be dropped at some point today. I personally am surprised that it is still up this morning. The Dweebs still expect some wrap around snowfall this morning and possibly this afternoon, but again, amounts will be light….. 1 to 6 inches over all…
The Upper Jet makes a return to the sierra by Friday……Some over running precip still possible mid-week.
Update late today:
The Next Short wave has moved on shore and will be climbing the Sierra tonight. QPF is about 1.25 to 1.4″ in the San Joaquin drainage by Monday PM. Considering early orographic’s, snow to water ratios which will be higher in this storm, and the fact that a secondary impulse will dive south down the coast in the Early AM, 16 to 20 inches on Mammoth MT seems in the ball park and between 8 to 15 inches in town. There may be a bit more shadowing with this system.
I have to say that this is not your typical ridge between weather systems. The models are bringing in a lot of warm air advection (over running). QPF forecasts are always problematic with (WAA). No doubt that there is going to be light snowfall now, later Tuesday into Wednesday. It will probably be around the 3 to 6 inch range on Mammoth Mountain and 1 to 3 in town.
Sorry for the bad news…It appeared earlier that we would get a clean break between storms mid-week, before the Thursday night/Friday storm arrived. Warm Air advection is often times associated with a lot of high elevation breeze. So be ready for that if you are on the mountain mid-week. Winds really pick up Wednesday night into Thursday.
The next significant storms looks to have a good SW fetch and although the main short wave splits a bit as in comes into CA, it should be a good precip producer for the Sierra.
Thereafter, a large synoptic scale, adjustment/long wave trof will provide for a moist, consistent flow of moisture into the Sierra next weekend, for at least light to possibly moderate snowfall. The Dweebs do not see another AR event until we approach the middle of the month of March. However, the pattern remains active.
The two-week outlook keeps the hits “right on coming”!
Dr Howard and the Dweebs……………………..:-)
Well Connected Atmospheric River stretches back to Asia as first major upper low moves in later today…..Winter Storm Warning hoisted for tonight through 10:00AM Monday Morning……2-1/2 feet possible for the town of Mammoth by Monday PM and 4 feet + Mammoth Mtn by Monday PM…….Storm Door to remain open in the 6 to 10 day period with a good storm every 3 to 4 days…….
Saturday March 5, 2016
Posted at 10:10 am by Howard
It’s almost ShowTime as an area of strong (UVM) “Upward Vertical Motion” moves in by 10:00PM tonight. The FOUS data for Fresno shows UVM increasing to a +28 by 10:00PM tonight packing the dendritic growth zone with more then it can handle. 500MB- 1000mb thicknesses fall from 554 DM to 542DM within 6 hours as the cold front comes through Sunday AM. By 4:00AM Sunday, the UVM diminishes to +12 so UVM still going strong! By 18Z Sunday (10:00AM) the UVM is down to +1.5, and 500MB Thicknesses drop to 535DM as the heavy snow turns to showers for Sunday afternoon. Note: a 500mb – 1000 mb thickness of 534 is a snow level of 3000 to 4000 feet.
Then UVM increases again by 10:00PM Sunday night, to +5.6 with a Thickness of 540DN. That means all snow for the entire Mono Country!! UVM increases up to a whopping +36 by 4:00AM Monday AM as the next cold front get ready to come through. By 10:00AM Monday, improving weather is expected with snow showers. The Winter Storm Warning is lifted at 10:00AM. Expect a break Tuesday through Mid day Thursday…..The next in the series of storms move in about Thursday Evening….
It is notable that the new GFS 12z deterministic Run for Saturday AM shows the updated 10 day QPF at 16 inches of water over the west side in the San Joaquin drainage….
Storm total for the Town of Mammoth is about 2.5+ feet and 4+feet for Mammoth Mt by Monday PM. Most of this will fall late tonight through Mid morning Sunday and again Sunday night into mid- morning Monday. The snowfall will be powdery Sunday night and Monday AM. Snow to water ratios will increase to 12 or 13:1 by Monday AM
Regarding Mondays storm…..
This storm may end up being a major problem for folks in Mexico as it digs sound over/or just off the coast of Baja, MX coast line. The GFS this morning brings thicknesses down into the 540s over the tropical waters of the Sea of Cortez and 550s DM south to near Puerto Vallarta, MX. The Sierra Nevada’s of MX, east of there stands a chance to get heavy snowfall which may become live threatening for any of the indigenous people that are un-prepared this upcoming Tuesday. The storm is showing up at some +5 deviations of normal for that area, this time of the year.
East Asian Jet Extension well in the models now with Best Storm Cycle probabilities for the Winter of 2016….AR Event Saturday PM to supply plenty of juice for the Pump….
Thursday March 3, 2016
Posted at 10:02 pm by Howard
This will be brief with a more detailed update later today:
Looking at the all the guidance, and if it is correct….we are going into one protracted storm cycle that may rival the “Miracle March” of 1991….. over a 15 day period…..
More details later today….
The Dweebs have been on family leave with newly born twins to take care of…. Both Jakob and Charlie doing well…..Both boys just escaping the stigma of Leap Day by a just few hours!
When the Dweebs updated some 5 days ago, it was apparent that both the EC and the GFS had come into better agreement and that the MJO was strong enough to bring significant upper divergence well east of the dateline and get the EAJ extended to California. It was a tough one without early consensus. After all, the EC is the better model right! 😉
The Dweebs want to make some important points here that deserve mention:
- The “AR” that is forecasted to set up has a long fetch across the pacific. Additionally, it has a double structure that is notable.
- The PWAT that is forecasted for late Saturday afternoon by the GFS is +5 sigma which is some 5 deviations above normal. There appears to be about 1.5 inches in the column forecasted.
- This is a notable AR and although it is nothing like what hit mammoth in February of 1986 or JANUARY 1 1998, this AR will supply a rich source of moisture for the dynamics to lift when it comes in Saturday night in Sunday AM. The CRFC “QPF” is about 3 inches of water within 30 hours. This is a hammer we have not seen this winter. The snow level will be tricky as microphysical processes maybe come into play as strong UVM develops later Saturday night. This may be one of those rare 3 to 4 foot snowfalls over night in Mammoth, above 8K, depending on where the snow level sets up. The Dweebs will have time to fine tune this tomorrow Friday afternoon..
Looking at the big picture, there are a series of systems headed into the area beginning Friday. The freezing level Friday is 10K so precip will be rain in town. Then there is the Saturday late afternoon/Sunday system which is the biggy. Another system will move in Sunday and will end Monday evening. There is another 1.5 inches between Sunday afternoon and Monday night, so another 18 inches over Mammoth Mt is possible along with some 6 to 12 in town. That system Sunday will be all snow. All toll, between Friday and Monday Night…..5.5 inches over the crest, or about 5 feet of snow is possible. Will update on QPF again Friday PM
There looks to be a break Tuesday through about Thursday with another system Friday into the following weekend. That system may split some….well have to see. Then another AR is hinted by the GFS about the 13th. The 10 day QPF from the EC is 7 inches or about 6 feet of snow over the crest. The GFS, 12 inches of water or about 10 feet. Take your pick…..Or better yet how about an average…..
The Dweeb forecast of 100 inches of snow over the pass at 10:1 is about 10 inches of QPF. Its possible….we’ll see. The Dweebs did say in the 2nd to 3 weeks of March, although the models are trending to split the upper jet south with southern stream energy heading south of us after week 2.