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!