HMT Forecast Fri 2/15/2008 1950UTC
Looks like same general pattern in GFS model run compared with yesterday,
though some details differ with short waves for mid-late next week. We still
have west coast ridging keeping things high and dry over the next few days.
There is a wave moving north giving precip to BC on Friday. An associated
front could bring some precip down as far south as the WA/OR border on
The initial short wave breaking down the ridge brings some light precip
(still about .2") from 21Z Tue Feb 19 until 09Z Wed Feb 20. The 00Z
ECMWF hi-res run is a bit shallower with this system compared with the 12Z GFS.
The PACJET is better established in the ERN PAC by mid-week (both in the 12Z
GFS and the 00Z ECMWF hi-res runs). Compared with yesterday's GFS deterministic
run the mid-week wave has less of a tropical moisture feed with lighter precip
amounts. The GFS yields just .2" between 06Z Thu Feb 21 and 00Z Fri Feb 22.
Time will tell if this represents a flip-flop in the GFS or a more consistent
trend, so an IOP is still slightly possible as early as Thu.
The following system looks a little more promising at this point with moderate
precip (about .7") coming in Fri Feb 22.
There is an interesting atmospheric river showing up between 140W and 150E
at 00Z Wed Feb 20. As the short waves approach the ARB however we see pieces
of the river being broken off (more than in yesterday's run) to quickly move
southward along the CA coast.
The long term GFS IWV forecast suggests drier conditions with maybe some weak
events around Feb 27 and Mar 1.