1 to 2 feet on Mammoth Mtn now with some additional accumulations possible today through Thursday AM….Earlier Forecast of 2 to 3 feet over the Upper Elevations still in Sight!
Wednesday December 3, 2014
Posted at 9:59 am by Howard
Although Snowfall ended early last evening, more could still occur over the next 24 to 36 hours….. Mammoth is between two dynamic systems. One to the southwest associated with a very active subtropical jet and the other associated with a weakening closed upper low off the coast of Eureka, CA. That system is expected to shift north over the next two days.
A vort center was moving north over Northern CA bringing heavy precipitation to the north of us and the Moisture Plume to the south promises more heavy rains for Southern CA before the day is over… In that the upper low off the northern CA coast is drifting north, as it weakens…..the Subtropical jet will shift north as well bringing more rain to Southern CA by late today.
In that the upper flow is still SW and very moist, there will be plenty of showers today and tonight enabling the Dweebs forecast of 2 to 3 feet above 10,000 feet to be reached. In that the snow level will rise to 8,000, Only light accumulations if any are expected for the town. The best chance will be this evening…..
The over all picture highlights the East Asian Upper Jet that had extended close to the west coast. However, it should be noted that it did not cross the sierra and so we did not get a cold sector and an upper trof passage. The EAJ is expected to retract now through early next week leading to partly to a partly to mostly cloudy weekend but dry. Early next week will be partly cloudy as well but milder. The Dweebs see the East Asian Upper Jet make a run for the coast again about the 11th or 12th. This is according to both week 2 ECMWF and GFSX global models. The storm track looks progressive and should cross the sierra. While storms of this weather type, like the one we just had, are typically more moist and are mostly absent of wind over the lower elevations, the ones that cross the sierra often times bring more snowfall as they have both warm and cold sectors.
As a note; Jan Null a retired Meteorologist from the NWS-SFO reported that through 7 am this morning….San Francisco had received 1.36″ of rainfall since midnight, which combined with 1.61″ received yesterday gives a 2-day total of 2.97″. With more rain on the way this looks to be the rainiest 2 days in San Francisco since at least January 2008.
As mentioned above…these two longer range models are more consistent at this time the extension of the EAJ through the sierra, beginning the following weekend/11th/12th. What is also interesting is that the new ECMWF EPS ensemble control; 200mb hpa upper jet, shifts south to between 30 and 35 North during the week 2 period. Within the upper jet are Jet-lets with speeds of 180+ knots at 200mb. Looking at some of the Canonical Ensemble Means…More and more are looking like an El Nino Influenced pattern. This is giving consideration of both pressure fields over the north pacific to the slightly higher latt’s and the development of a strong East Asian Upper jet and its extension to the west coast. IE the -(TNH) Telelconnection Pattern for our not to distant future. It appears the next wave of systems the 2nd half of this month may be even stronger than what we have now….A lot will depend upon the strength and location of the MJO and GWO.
Dr Howard and the Dweebs………………….:-)