11/27/2020

Monday AM update

It was interesting to watch a fairly significant MJO build into Phase 7 with projections into Phase 8.  This is an area in the winter noted for Atmospheric Rivers. Up until just a few days ago, non were being forecasted by the global models.   Yesterday and the day before, a moderate one showed up on the coast with its extension weakly into the Central and Southern Sierra. This mornings models runs showed a slight backing off on duration Late Thursday and Friday as the moist band pushes through rather quickly. The Integrated Water Vapor Transport from Scripts shows this as a weak AR, inland at 37.5N/120W (300) KG/ms. The duration is about 12 hours.  The fetch on this AR is not all that long.  It begins Thursday night and lasts into Friday. Preliminary snowfall amounts suggest 3 to 5 feet by next Monday. This pattern will have to be watched over the next few days to see how it all holds together.  Again this 3 to 5 feet is very preliminary and contingent upon the strength and duration of the IVT.

 

More tomorrow…….

 

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It was a beautiful Thanksgiving Day and Friday with high temps in Mammoth the mid 50s for the Friday. Plenty of high clouds swept through Southern Mono this Saturday AM associated with weak WX front. The first in a series of short waves will began their march into the west Monday into Tuesday. The first system will be mainly wind, cooling and some snow showers with no significant accumulations expected for Monday or Monday night as the upper jet sweeps NW-SE through Central Nevada.  Subsequent systems will dig a bit further west for the potential of more significant snowfall. This looks to begin next Thursday into the weekend.

Both the European and GFS global Ensemble models have enough over water trajectory to bring as much as 12 to 18 inches by Saturday Morning according to this mornings 12z run of the ECMWF ensembles…..Then additional amounts over time. Looking at the GFS ensemble’s for the same time frame. Some 6 to 12 inches is indicated at this time through Saturday AM on the Mountain. Both models show amounts 2 feet or more by the following Tuesday the 6th on the Mountain.  Remember, this is not a forecast, it is just guidance at this time. The Dweebs will keep you in the loop this upcoming week!  🙂

La Nina;

La Nina is at it peak now for the season and is expected to begin weakening after the first of the year toward ENSO neutral. This is expected by February/March with a new El Nino developing as early as this Summer. Year 3 La Nina’s are very unusual leading to the odds being very good that ENSO Neutral to El Nino conditions will develop over the Equatorial Central and Eastern Pacific during 2023.

 

Dr Howard and the Dweebs………………….:-)