Weakening system to bring some snowshowers to the high country Thinksgiving……Global Pattern going through Major Transition…..+Phase PNA pattern the likely result……
Tuesday November 22, 2011
Posted at 9:40 am by Howard
OK….this is where we are at….
Over the next few days the split flow pattern over the Eastern Pacific continues with the likely result, Mammoth getting skunked as far as more snowfall this week. To be sure, I will update one more time tomorrow. This is not to say that we will not get some snow-showers….However a replay of last Sunday is not likely. The reason why I say this is that non of the models including the global ones bring the splitting system close enough to the coast to bring a front into the Sierra. However, there could be some showers as the storm shears some moisture east. At the moment, the Dweebs feel that nothing measurable is likely…..but I’ll look again tomorrow AM.
Beyond Thursday….we ridge up…..
The Key Teleconnections for the GFS ENSEMBLES show the Positive Phase of the PNA. IE Far Eastern Pac Ridge/Eastern Trof.
However, The AO is positive so lower pressure is expected to continue over the far northern Latts
The NAO will be neutral to positive as well….not good for any extended term east coast long wave trof.
The Dweebs sense is that we will be going through a dry transitional period over the far west into early December or even, some what beyond. Some of the models bring some energy through the ridge and some down its back side as an inside slider over the next week or two. We can always get snow showers from such systems but those will not get us where we want to be.
The Good News….
The SSTA foundation is solid.
Lots of cold water over the far Eastern Pacific. All the warming that occurred in the late Summer and early Fall is gone. There is a nice warm water pool centered about 170W. It extends east to north of Hawaii, and west to Japan. So the PDO is strongly Negative….good for west coast storms. The QBO has transitioned to its weakly negative stage. Winds above the trop/equator now east to west is some areas…….suggesting a weaker Hudson Bay low if the QBO continues to strengthen in the negative phase.
Most of All, there is “little sign of Blocking in the Greenland Area!!”. Persistent Blocking Near Greenland, Intensifies the Hudson Bay Low which can support a persistent West Coast long wave ridge. If the east stays mild…..it is only a matter of time before winter returns to the high country!
I think that Blocking will be the key over the next Few Weeks or should I say the absence of blocking over/near Greenland.
MJO Update later today…….
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.