Wettest October In Years; Much More On The Way

October 25, 2012

We’ve seen about 18 hours of dry weather now, and I don’t expect much rain in the next 24 hours.  But after that the firehose of warm subtropical rain turns back on in the Pacific Northwest.

We are just a few tenths of an inch of rain away having the wettest October since 1997; shouldn’t be hard to reach that by Saturday.  We’ve been in a cool and wet airmass for the last 6 days but that’s about to change.  Through the foreseeable future (the next 7-10 days) an upper level ridge, or at least higher than normal upper level heights, will be centered on or just off the West Coast.  This says warm and wet most of the time.  And models are responding by generating a LOT of rain.

Here’s the 72 hour rain forecast from Saturday to Tuesday afternoon from the 00z WRF-GFS, showing 5″+ just in that period in the Cascades.  Even the driest parts of the valley get maybe 1.50″

And the 12z ECMWF 7 Day rain forecast:

Both models are extremely wet.  You don’t get much detail on ECMWF because it’s a global model, but you get the idea.

We could end up with another 2-3″ rain before the month is up; if so, that would get us up in the 5-7″ range.  So much for a developing drought!

Chief Meteorologist Mark Nelsen