Thursday AM:

Weather systems over the past 6 weeks have built up a base depth of between 2.5 and 4 feet over Mammoth Mt. All ski resort corridors are now open including Little Eagle, Canyon Lodge and the Main Lodge. The Dweebs expect a few more inches of snowfall Friday into Saturday before we ridge up Later Saturday into Monday.

The Dweebs Weather update shows a beautiful today with lots of sunshine…there will be clouds as well that will increase over night. Breezes will be light this morning but increase tonight. The next and last in the series of weather systems will move through the sierra Friday into Saturday bringing light amounts of snowfall. Possibly a few inches. Thereafter, we go dry Sunday through Wednesday.

The next weather system for Christmas Eve and Christmas Day is being handled differently by the global models. The Euro brings a cold system down the coast with snowfall for the Eastern Sierra while the American models bringing some wind and cooling but keep the weather dry. Stay tuned to this change. I expect better visibility “in the models” later this weekend for Christmas Day!

Dr Howard and the Dweebs……………………………….:-)


Wednesday Evening….

A quick look at Fridays system, there are two distinct areas of vorticity. One that comes through Friday afternoon and the other very late Friday night into Saturday AM. All in All….not a system to write home about but enough to get 1 to 3 inches of snowfall by Saturday AM

A warming trend is likely Sunday into Tuesday with a pretty big ridge building in…then…..a high latitude block in the northern branch of the westerlies retrogrades and allows a pretty strong short wave carrying Modified Arctic Air south down the coast into northern and Central CA Christmas Eve.

Quick look at the extended guidance of both the ECMWF and GFS. (Subject to change) They both show a cold system digging SSE down over the far west Christmas Eve. By Christmas Morning the -18C Isotherm is over Eastern CA. That is temps around -2F at 10,000 feet and in the low single digits in town of Mammoth Christmas morning if it verifies.

There could be some light snowfall as well depending upon how much over water trajectory there is with the upper jet. So the Dweebs will keep a weary eye out on this one.  If this is works out, Santa will get great gas mileage over night as the flow is right out of the north.  And….Arctic air will invade the Great Basin as well.  This is quite the cold system and like a giant lake effect of cold air over the warmer then normal waters of the pacific ocean.

More Later……

Wednesday AM:

Another System in the Split breaks up over the Central CA  Interior.   Just a dusting this AM.

Next and last system Friday/Ngt will not split. However, it is pretty weak.  We still could pick up a few inches in town and 2 to 4 over the higher elevations by Saturday AM

After Saturday, we ridge up into Mid Week next week.

The Dweeber……………………..:-)


Finally, a vort center progressed through the Sierra Early this morning. It was enough to drop some 6 to 8 inches in town and 12 to 18 inches up on Mammoth Mt. Not bad for a system that did not have any upper Jet support in this area. It came in before the split could do its damage. It was a Cloudy day today with some light snow shower activity as well.

The Split Flow pattern is coming to an end by this weekend. However, not before another system comes in tonight and yet another Friday.  There is the possibility of another 5 to 10 inches falling on Mammoth Mt between tonight and Wednesday PM. Then one last weak system Friday into Early Saturday AM.  It all depends on how well we do with that split flow.


Weekend Outlook:

The transition from a Split-Flow pattern to a pattern in which the northern branch of the upper Jet dominates will effectively take California out of the Current Storm Cycle by the end of this week. However, not before we tally some 4 to 5 feet of snow as it fell by the inch, over the crest the past 6 to 10 days.

This weekend, all forecast models show height rises over the CA State with a NW flow aloft. This is a dry pattern at this latitude and one that will be a bit breezy over the crest early in the weekend. Further height rises occur as a rather large Anti-Cyclone builds NE from the SW. Thus strong ridging is expected into California, Sunday and Monday. Temps will moderate up over the weekend and especially early next week.

Longer Range:

Officially both 6 to 10 day and 8 to 14 day models are both warmer and drier than normal through year-end for CA.  However, The ECMWF Control has a strong short wave coming into CA, late Christmas Eve and Christmas Day. In contrast, its Ensembles just show a strong WNW upper Jet at that time frame. (Northwest Slider) That would primarily be a Wind and Cooling Event with a slight chance of snow showers.  Looking at the GFS, there is a chilly system dropping into the Pacific North West. That also is a dry pattern for the time frame. At the Moment it just looks cooler and breezy or windy. Now with that said…it is what happens after Christmas and over the last weekend of the year that looks promising, as the Eastern Pacific Ridge is forecasted into Major Retrogression Mode.


The Dweebs will keep an eye out for the Christmas Day system as well as the transitional pattern that will follow, the end of the year……


Dr Howard and the Dweebs……………………….:-)