# Friday, January 01, 2010
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NAM 500 mb Heights 12/05/09 18z Click
AHPS 90 Day Precipitation (Percent of Normal)

In terms of typical El Nino impacts, Southern California is still waiting. If you squint your eyes and have a good imagination, there is a hint of an El Nino rainfall pattern on the West Coast, but rainfall over much of our area ranges from a little below normal to a little above.

Including Wednesday's meager rainfall, Downtown Los Angeles is now about 1.1 inch above normal for the water year. That sounds great, but is a little deceptive. Some stations are well below normal and some well above. For example, Camarillo is 1.4 inches below normal, and Santa Barbara 2.3 inches above. According to the AHPS precipitation map, some mountain areas of Santa Barbara have had 200% of normal rainfall the past 90 days.

As expected, the Global Wind Oscillation (GWO) did orbit up into the positive AAM side of the phase space; but as feared, Indian Ocean/West Indonesian convection appears to have (once again) quashed the positive response. The average relative AAM anomaly for the period November 1 to December 29 remains slightly negative, and total global relative angular momentum is just about where it was at the beginning of November.

Updated January 2, 2010. Recent runs of the GFS show the Pacific jet extending and then collapsing into another trough off the West Coast during the week. This seems a little late to be directly related to the recent GWO phase 8-1 transition. A continued orbit of the GWO to phase 2 and 3 would be expected to shift the jet north and could result in another highly amplified wicked ridge of the west. Today's 18z run of the GFS plows the trough into a resistant ridge with most of the energy going up and over the ridge. The 12z ECMWF splits the trough and attempts to bring part of it in under the ridge. We'll have to see how things develop during the week.

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