When going east of the Cascades, the weather becomes very dry and the
land almost desert-like. This is because the Cascade mountains force
most precipitation to condense and fall as rain or snow in the
mountains. This forms a rain shadow to the east. There are also the
Olympic mountains just west of Seattle. The question is, why doesn't
this mountain range have the same effect, leaving Seattle in a dry
climate?

Here's some detailed information about the rain shadow:
http://answers.google.com/answers/threadview?id=93878

But the Olympic Mountains are not a restrictive barrier, so moisture
flows around them and creates a variety of micro-climates, including
wet areas along the Hood Canal and the Everett "convergence" zone:
KOMO-TV
"What is the Puget Sound Convergence Zone?"
http://www.komotv.com/weather/faq/convergence_zone.asp

Good live pictures, including an "animated" cloud flow, are available
from Intellicast:
http://www.intellicast.com/Local/USLocalWide.asp?seg=LocalWeather&loc=ksea&prodgrp=RadarImagery&product=Radar&prodnav=none&pid=none

Google search strategy:
"Puget Sound" convergence zone

Best regards,

Omnivorous-GA

Quick and to the point with great hyperlinks that answered my question in full.

there is a rain shadow in the seattle AREA due to the olympic mtns.  try this link:

http://sequim.com/about/weather.html

Here's some detailed information about the rain shadow:
http://answers.google.com/answers/threadview?id=93878

But the Olympic Mountains are not a restrictive barrier, so moisture
flows around them and creates a variety of micro-climates, including
wet areas along the Hood Canal and the Everett "convergence" zone:
http://www.komotv.com/weather/faq/convergence_zone.asp

Google search strategy:
"Puget Sound" convergence zone

Best regards,

Omnivorous-GA

Thanks so much Omnivorous. Your answer was perfect.

Pennypacker --

Thanks so much (and it's converging in the convergence zone this
afternoon, I can faithfully report).  I can either post the notes
above as an official Answer if you'd like.

Best regards,

Omnivorous-GA

Yes, I see that there are some ugly clouds in Seattle right now. Looks
like the convergence zone headed right over the city. Please post your
comments as an answer. That way I can pay the listing price. Thanks
again.

re:
Quick and to the point with great hyperlinks that answered my question in full.

If that is the evaluation of this - then what would it take to give 5 stars?