YES YES YES! Do it! I predict it will be very well attended.

Seattle has the most LW readers of any city in the world without a meet-up!

Visits to LW the past year / Meetup

• London 56,788 Yes
• New York 41,422 Yes
• San Francisco 29,036 Yes
• Melbourne 24,199 Yes
• Seattle 19,475 No
• Chicago 17,235 Yes
• Sydney 16,806 No
• Helsinki 16,371 No
• Los Angeles 14,083 Yes
• Cambridge 13,622 Yes
• Philadelphia 11,727 Yes
• San Jose 11,702 Yes

11000+ Visitors

• Moscow
• Austin

10000+ Visitors

• Washington

9000+ Visitors

• Atlanta
• Brisbane
• Dublin
• Houston

8000+ Visitors

• Berkeley
• Portland

7000+ Visitors

• Pittsburgh
• Toronto
• Paris
• Denver
• Sunnyvale
• Cambridge
• Redmond

6000+ Visitors

• Auckland
• Singapore
• Madison
• Cupertino
• Boston
• Perth
• Brooklyn
• Minneapolis
• Ann Arbor
• Oxford
• Adelaide

5000+ Visitors

• Canberra
• Vancouver
• Berlin
• San Diego
• Mountain View
• Bellevue
• Vancouver
• Dallas
• Durham

4000+ Visitors

• Bangalore
• Stanford
• Edinburgh
• Budapest
• Columbus
• Riga
• Manchester
• La Jolla
• Warsaw
• Sacramento
• Raleigh
• Prague
• Bristol
• St. Louis
• Boulder
• Ljubljana
• State College

EDIT: Added 13-50, these are total yearly visitors, not hits

All these cities had at least 500 unique visitors the last month. I would be confident starting a meetup anywhere with over 5000 visitors / year... all of which have at least half the readership of cities that already support meetups now. Other cities that look promising but are just on the borderline are Oslo, Hong Kong, and Princeton.