If you saw the Minnesota game Sunday then you know that there was a Cold Air invasion from Canada over the weekend. The Cold has advanced SE and is part of a slowly progressive long wave trof over the Eastern US. Chances are good that if this was not a strong El Nino Winter,  that this cold trof would have gained a foot hold over the Eastern CONUS and it would have been Ridge City over the west for 3 weeks or so…..  However, the southern stream is already coming to the rescue as it is working hard to carry the meridial flow and its cold air out off the east coast by Tuesday night.    Thus the current shortened wave length will become elongated and negative tilt, as the cold air get flushed out over the Atlantic.  At the same time, the storm door will open over the far west as a series of light to moderate precipitation producers move through the west coast.  Moderate precipitation snowfall wise is between 6 and 18 inches here in Mammoth, over a 24 hour period….  As with any pattern change, the timing of the short wave will be an issue this far out. At least until both the ECMWF and the GFS come into better agreement…  At the Moment, they both agree on the timing of the Wednesday through Thursday short waves and precipitation amounts.   It is the Friday through the weekend holiday that some fine-tuning will be needed…..

 

Although there will be a pattern change, more important changes are coming into the picture in the form of teleconnections.  Its the AO….It is flipping back to positive according to the European model by the 20th…and eventually strongly positive may I add. So this means that the flow will become more progressive as lower pressure develops over the Arctic. This sends the east back into a pattern of above normal temps over time and the storm track a bit further north again. Northern CA and the pacific NW are more apt to get more rain again during week 2. Pretty unusual for a Strong El Nino!  I noticed that a strong Potential “AR’ event may develop after the MLK holiday next week for Northern Ca and Oregon.  This should at the least get us out of the colder than normal temps in Mammoth with higher heights and so we can get rid of some of the ice dams on the roofs…  However with that all said, we need more snow as the sierra snow pack is again below normal. Today we are more than 70% below at this time…