Matthews will challenge Democratic 21st District State Sen. Marko Liias in the Aug. 5 primary and Nov. 4 general election.
The two will be alone on the primary ballot, meaning that both are almost certain to advance to November.
Matthews is a retired Northwest Airlines pilot and Boeing test pilot. Before moving to Mukilteo, he was a member of the Shoreline School Board.
Guest speaker at the Tuesday event will be Republican former State Attorney General Rob McKenna.
Organizers ask attendees to call 425-422-3105 or 253-753-4750, or to send an e-mail to firstname.lastname@example.org.
Matthews his raised $3,050 for the campaign and spent $700. Liias has raised $28,089 and spent $500.
Liias took the position by appointment in January after spending six years in the State House of Representatives.
The 21st Legislative District includes most of Edmonds, unincorporated areas north of Edmonds and Lynnwood and northeast of Lynnwood, all of Mukilteo and part of south Everett.
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