Most courts in Washington will not issue a warrant immediately. The court will, however, authorize the warrant immediately, but it usually does not arrive to law enforcement until the close of business, so as a practical matter, if you appear personally (not over the phone), you might be able to pay a fee to quash the warrant and reschedule your hearing, unless the judge set a bail amount.
To avoid getting arrested, you should call the court first and see if a warrant was authorized. If they do not respond, assume it was and leave a message. Also send in a request to schedule a quash warrant hearing with the court if you can't arrange that over the phone. If you learn there is a bail amount required, then you should go into court prepared to pay that amount. Also, you can contact a bail bond company in advance and ask them to be prepared to post a bond on your behalf.
The last strategy for avoiding jail is to contact the prosecutor's office and arrange for a plea the day you appear in court, especially if you can negotiate a deal that involves no jail, or maybe just jail alternatives. that's where hiring a good attorney always helps. Read more at mytrafficman.net.