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HMT Forecast Thu 2/14/2008 2000UTC

Rather sunny and dry over the ARB with a few leftover wave clouds over the
Sierra Crest today. Some light precip was scattered in the ARB the past
24 hours with .12" at Greek Store. The tail end of the trough axis is currently
moving southward in SRN CA, with most precip well inland in the intermountain

There are some waves coming in through the Pacific being diverted northward
by an offshore ridge. There is a decent jet in the WRN Pacific that moves
eastward in the GFS during next week. This should gradually break down the
offshore ridge as we enter the mid-late next week time frame.

From today (Feb 14) to Feb 16 we have a wave going north bringing precip into
BC. The next system starts to break down the ridge with light-moderate precip
(.2" in the GFS) arriving in the ARB Tue Feb 19.

Following that a reasonable looking PACJET directs precip into the ARB with
heaviest amounts late Wed Feb 20 into Thu Feb 21. The GFS yields some healthy
precip amounts totaling about 2.8" as lighter amounts trail off into Friday.
This shows an atmospheric river signature briefly though it starts to break
up as it approaches CA. Nonetheless the GFS forecast is for 35-40mm of IWV
reaching SFO for 00Z Thu Feb 21. We'll want to watch to see if this holds
enough in future model runs to suggest calling an IOP.

Time will tell whether we will get a long term pattern change to more zonal
flow or if the west coast ridge returns after next week.

Steve Albers