Fair Weather For the Next Two Days Then Eastern Pacific Troughing Setting Up With Snowfall Possibilities Next Week….
Friday March 9, 2012
Posted at 9:49 am by Howard
Brief Update Saturday:
Trend is intact for an Eastern Pacific long wave Trof to set up over the next few days. Although the upper jet still favors the pacific NW and Northern Ca through Mid week….The systems become increasingly wetter by mid week. As we get to Friday, Strong upstream amplification occurs on both EC and GFS models. Thus confidence remains high for a significant storm that will bring several feet to the high country of Mono County beginning next Friday through St Patty’s Day weekend. The storm is cold and the Powder by the end of the week could potentially be the deepest and best of the year. (Don’t put your boards away yet!)
This mornings satellite showing the upper ridge right over the golden state and 12z gfs forecast run showing best warming aloft today with the calmest winds over the Northern half of Ca. The southern half of the state has off shore flow with warming as well. Expect highs today in Mammoth to push over the 60 degree mark for the first time this year….
Temps in the Owens Valley will move into the 70s with little change in temps Saturday for the Owens Valley. Mono County will be a little cooler, with an increase in breeze and high clouds by the afternoon. The upper ridge will begin to both weaken and shift east.
Next week the well advertised long wave trof is still expected to set up over the Eastern Pacific as increasing jet energy and eventually amplification upstream drives the upper jet toward the southern part of the state the 2nd half of the week. As a note, the MJO did have the effect of retrogression over the north pacific this past week. However the pattern over the pacific has not been amplified enough to get the upper jet south down the west coast. That may have something to do with the +AO? Maybe, maybe not. All I know is that mother nature has been pretty stingy this year with high latitude blocking in the areas that are most conducive to central west coast storminess. The Equatorial-ward trajectories of Arctic Air over the Western Hemisphere have been both anemic and infrequent. As of note, according to the latest snap shot, the AO will be trending toward neutral next week and possibly even briefly negative by St patty’s day.
The Dweebs have taken a look at the 00z GFS 3, 5, 8 and 11 day means as well as the amplitude of the wave pattern across the north pacific next week.
What is note worthy is that for the first part of next week the front left exit region of the upper jet with the best forcing favors the Pacific Northwest beginning Sunday with the Rt rear entry region favoring Northern Ca. So once again, the Northern Sierra will get the best of the precip the first half of next week. I will note that the mid week short wave is definitely wetter with a lot of pacific moisture being entrained into the system. Some of that will bring us snow fall here in Mono County, Tuesday into Wednesday. However, it does not appear to be big amounts. Beyond mid week, the most significant system for the Mammoth area appears to be associated with the most amplification of the long wave in addition to progression of the same, as we go from Friday the 16th through Monday the 19th. That appears at this time, to be the best “IOP” for the Central Sierra next week!
More updates on the way later this weekend……..>>>
Dr Howard and the Dweebs……………………….:-)
MJO…the Hows and Whys: (Subseasonal Synoptic Model)
The framework for the model is global atmospheric angular momentum (AAM), which varies with the amount and distribution of westerly flow and mass in the atmosphere. The MJO produces a robust signal in global AAM because as equatorial convection anomalies propagate eastward the accompanying surface wind and pressure anomalies induce anomalous mountain and frictional torques. The torques exchange angular momentum between the atmosphere and the solid earth. The MJO mountain torque comes primarily from subtropical topography and depends on the MJO’s surface pressure anomalies and their placement relative to the African Highlands, the Himalayas and the South America Andes. Momentum and heat transports by atmospheric eddies organize the angular momentum produced by the torques and give rise to a zonal mean wind signal that propagates coherently poleward from equatorial regions into the subtropics. Such anomalies are strong enough to influence storm track variability and wave energy dispersion in mid-latitudes.
Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.