Dweebs were back at it this morning with our first fall forecast. Of note, the MJO is amplifying in phase space 8 and is expected to track east into phase space 1. This area of tropical forcing moves through the Western Hemisphere and Africa next week. Highlights of this action now, are the intense mesoscale clusters developing from the ITZ, drenching parts of the Hawaiian Islands.  In looking at the IR Satellite & 200-hpa Velocity Potential Anomalies for the 25th of September, this is possibly in reaction to a developing Wave-1 configuration and strong upper divergence centered SE of the Hawaiian islands over the ITZ. This is likely in relation to the developing MJO projection into Phase Space 8.

This would be classic Pineapple Connection, a form of an AR) for west coast except that it is late September and the results from the jet stream are much weaker. However, they are substantial enough to build Upper High now off the coast of the Pacific NW, Northwestward, forcing the Negative Phase of the Eastern Pacific Oscillation blocking pattern (-EPO). This results in the undercutting of the westerlies and a relatively minor closed or cutoff low for Northern California Sunday. Sensible weather for Mammoth will be breezy, cooler weather and a chance of showers early next week.  As a note, There is a TS that will track up the Baja Coast this weekend and as a long shot, get entrained within the Trof off the west coast. This pattern is only remotely possible at this time as model simulations do not favor it at any significant degree…..However, it is possible.  San Diego would benefit at best, but more likely northern Baja CA to AZ and possibly Las Vegas early next week.

Longer Range outlook for October favors periods of cooler than normal weather with some possible cold storms, during the month. Mammoth will likely get a few periods of snowfall during the month of October.


Dr Howard and the Dweebs……………:-)