Strong Moist Belt of westerlies will remain well north of California into the pacific NW and BC….Much Above Normal Temperatures makes a return to Mammoth Thursday into Sunday……
Wednesday October 7, 2015
Posted at 9:07 am by Howard
Partly cloudy skies continued most of the day Tuesday as the remains of the closed low that moved through CA Monday and Tuesday…slowly moved east over Arizona last night. That system is progged to move into Western New Mexico, then drop south to NW Mexico by Thursday and over the Sea of Cortez by Saturday. By Sunday and Monday it will be off the coast of Baja over the Eastern Pacific. Meanwhile, a strong moist belt of westerlies will bring a lot of rain to Washington State and BC today and through the weekend. Some of this rain over the next few days will be from a tropical storm now east of Hawaii. So an AR event for the Canadian Coastline and Washington State is expected.
Central and Southern CA will have a strong warm up between today and Friday. High pressure aloft will nose into Central CA with 500mb heights about 594DM. This will make for highs in Mammoth near 80 and Bishop temps climb to near 90 by Friday, and stays there through Tuesday.
Concerning the upper low that circles back into Southern CA next week, that system may bring some showers by Tuesday or Wednesday next week for So-Cal. High temps will pull back a bit next week as the upper high this weekend breaks down Sunday. However, low to mid 70s are still likely through Wednesday here, a full week away.
According to todays inter-seasonal forecast for the CFS V2
The weather will be come much cooler the week “beginning” the 19th of October with at least some light precipitation for Central Ca that week. The last week of October is when a big change is indicated for our area with the first substantial snow storm arriving that week. No date specified yet. Again, the Storm or Storm’s are likely to be cold with snowfall as the temperature anomaly shows well below normal temps. The Dweebs will update on this change, “next week” to see if some fine tuning can be done….”either way”. 😉
Note: This product is a inter-seasonal product that is ensemble driven; not a specific snapshot of a days worth of data.
Almost done with Platinum Powder update, “El Nino 4”. Just waiting for both the CPC update and IRI-CPC
Upper Low Now Moving South through the Pacific NW will increase breezes this afternoon with a upper winds becoming easterly by Sunday….Some light snowfall expected……Warming trend later next week with the eventual return of low 70s by next weekend end….
Saturday October 3, 2015
Posted at 1:27 pm by Howard
The Forecast models are in good agreement in bringing a closed upper low south from the Northern CA coast then SE along the coast line or just inland over Ventura County. It then is expected to shift east Monday….
The majority if the precipitation will be over the Southern Sierra Near Mount Whitney. Over a foot of snow is possible there. The other area that is under the gun is over the White Mountains and the mountains around Death Valley.
Closed lows of this type are difficult to predict, precipitation wise, as there is not a true active front that comes through. It is rather an area of surface, mid or upper level convergence called a deformation zone that will come through Mammoth Sunday morning, and part of the afternoon. This deformation zone will shift south with time and may stall out over the southern sierra. Where it stalls is the area with the most precipitation expected. In this case the upper low is forecasted to shift east through the Mojave Desert and so the deformation line will slow and pivot over the Southern Sierra and Owens Valley. Mammoth should receive at least 2 to 4 inches of Snow, Sunday into Monday at and above 9,000 ft.
However, this system has a convective element to it, and should a thunderstorm develop over night or in the Morning, several more inches is possible; even at lower elevations. Otherwise, over the lower elevations 7000 to 8000 feet, there will be snow pellets and brief snowfalls possible. For those in the back country, be prepared for cold wet conditions with at least a light snowfall, in the 2 to 6 inch range.
Dr Howard and the Dweebs……………………………….:-)
Mid Latitude Trof Spreads Subtropical Moisture into California with showers expected by late morning and into the afternoon….Snow Level is above 10,500 feet……Clearing Friday then fair Saturday AM with the next system colder with the potential of several inches of snowfall above 8K Saturday Night into Monday Night…
Thursday October 1, 2015
Posted at 9:36 am by Howard
Thursday Afternoon Update:
Just saw the finished run of the 12Z Thursday ECMWF.
It is remarkably in step with its previous runs and preferred over the 12Z GFS for that reason. The Dweebs are not sure why the GFS is taking the upper low down the coast to LA Sunday night and Monday. However, the Dweebs are not buying into it.
This is actually a better storm for Mammoth in which the QPF will bring higher snowfall amounts. The upper center is located near San Jose Sunday at 5:00 AM. It then remains quasi stationary for about 12 to 24 hours before heading SE right down the interior of California, then exiting out to Arizona crossing the Colorado River, Tuesday afternoon. So Sunday and Sunday night some good convective snowfall possible above 8K, then some possible upslope as the low provides some backwash, as it moves out of the San Joaquin Valley into Kern County Monday evening.
As a note, to back country travelers, I can not emphasize enough for the folks that are not experienced “winter” back country travelers, to postpone until the middle of next week…. It will be cold, wet, snowy and miserable, late Saturday night though at least early Monday…. The Dweebs will come out with an estimate of snowfall for the Sunday/Monday period on Saturday Afternoon.
Skies continued to be cloudy Thursday morning with SFO Radar showing an active front from Santa Barbara to Fresno to Tahoe…..shifting eastward. Rain showers a good bet later this morning and afternoon with a few embedded TSRWs. The more important story is the Colder closed low that will wind up as it drops out of OR, and spins up along the Northern and Central Ca coast Saturday and Saturday night. The NEW 12z GFS has the closed low dropping further south now down to the Channel Islands by late Sunday night and as far south as Catalina Island by Monday Night. This is much further south and west than both the 00Z Gfs and ECMWF showed. Additionally, it has plenty of time to generate a lot of moisture over a 24 hour time frame. The big issue now is that if this track is correct, the storm will have significant upper jet energy over the very warm waters off the Southern CA Coast that is some 75F degrees. The diabatic heating off the warm SSTs, off the SC coast could make for some Severe Weather as it swings inland Monday night and Tuesday AM for Southern CA. the Dweebs will update this afternoon to see what the 12z ECMWF show with the track as well. As a Caveat….This new track is a big departure from last nights run…
Potentially…this could be quite the rain and snow producer for the Southern Sierra south, depending upon the track. Stay Tuned!!
Meanwhile, the east coast of New England looks to dodge a bullet as the new gfs takes the track of Joaquin more in line with the ECWMF. Wow! what a model the ECMWF is! It blows our GFS away at a distance!