Dave Reynolds scenario
The following is from John Brown's 2 Jan 07 HMT discussion:
Farther ahead, I see no IOP prospects arriving before
midweek next week. Beyond this, the "deterministic" (T382 resolution) GFS run from 12Z this mrng
has a downstream amplification producing a massive ridge building into the Arctic followed by amplification of the downstream trof. This trof cuts back off the west coast of North America to ofshr the Pac NW and northern CA by the middle of next week. A few of the ensembles are in agreement with this scenario. Dave Reynolds points out that this could dynamically phase with the current MJO wet phase that is advancing Ewd from the Indian Ocean and has reached near 120E (see Klaus Weickmann's posting of yda). Dave believes there is a possibility that this could develop into a prolonged wet period for Nrn CA, with a westerly flow connection developing underneath a high latitude block between the offshore-cutting-back North American trough to the east and an eastward extention of the east Asian jet from the western Pacific. Such scenarios can bring heavy low-elevation snows with the cold cut-back trough followed by warmer storms once the cross-Pacific jet gets established. Something of this sort would help salvage this rainy season from the potentially serious dry spell that has afflicted central and parts of northern and southern California.