the wet season commences

The end of September shows an 'interesting' weather pattern. Since that's two weeks away it's not likely to pan out - but models have fooled us before by being right!

This is the model output for nine days from now. It shows moisture transport at high altitudes, where atmospheric rivers are most clearly visible. Nothing for the next week.. then this. And another a few days after!

I'm leaving this graphic as a placeholder, so next week we can see what the near-term models have to say about it..

Might be the right time for a late-season dose of weed 'n feed?

Update 9/18 8pm

Each model run (updating left to right) is getting more energy lined up along the coast, and wow those arrows are getting long and dark! By Tuesday it pushes inland while dissipating - but some folks would really get hosed if this comes true. 

NWS offices in Seattle and Portland are now paying more attention, and some are suggesting 3" totals on some model variants. I'm showing the upper-air Water Vapor Integrated Transport data from u.Wash WRF model, which shows atmospheric-river activity better than many 'standard' models nearer the planet's surface (this also runs past seven days, unlike many other reference points).

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9-21 Update: the strongest energy is exhausting itself before landfall now, so it's still coming - but not as excessive compared to earlier forecasts. 

Through Wednesday we could get 2-3" total rainfall. Another chunk of damp energy comes later in the week.. so reaching our September normal rainfall (just under 2½") looks like a pretty sure thing! *

Map at left shows total through Thursday PM.

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What really happened: it seems the low-pressure offshore strengthened more than models had forecast, so the main energy streamed north offshore of us and slammed Vancouver Island. As of Wednesday at 9am, we've had about 1½" of rain - so half of the higher-end model estimates. Even the coast stayed near 2" .. a short distance west would have been in the thick of it! So not precisely correct, but a very good forecast a week beforehand.

* That "sure thing" September total is definitely optimistic now. We're over 1/2" short of the mark and the 30th looks dry.