12z GFS Ensemble Chart

February 12, 2013


For regular folks, read the previous post below, this is just to talk about a chart with a whole bunch of lines.

The 12z GFS is in and it looks exactly like last night’s 00z ECMWF showing a cold trough dropping over us next Monday night & Tuesday.  Possibly cold enough for a dusting of snow all the way to sea level if everything works out right, but it’s a real marginal setup with most energy/precip heading farther south from Eugene into N. California.  Tuesday could be a snowy drive down I-5 in SW Oregon and into the Siskiyous.

Then there are still hints that we’ll be close to snow again around Mon-Tues the 25th/26th (I know, 13 days away).  Although the 12z GFS appears to be one of the coldest members of the ensemble, there are others cold too.  Interesting feature to watch…since there is nothing else to do during 3 days of gloom and mild temps anyway:


1:30pm…here is the 12z ECMWF ensemble chart:


2pm…and this is interesting, the 360 hour ensemble maps (about Day 15) from the GFS, 00z GEM, and ECMWF models.  All very similar at the very end of the month with the average ridge position slightly farther offshore.  That allows colder troughs to come much closer to the west coast.  How close remains to be seen, but you can see why there would be such variation in the ensembles above depending on the ridge position.