Forecasters expect Wednesday will be noticeably windier than Tuesday and firefighters warned that vegetation is critically dry.

A red flag warning for critical fire danger, due to strong winds and low humidity, will remain in effect until 6 p.m. Wednesday for the San Diego County mountains and inland valleys.

Red flag criteria is generally when relative humidity is at 15% or less, combined with sustained winds and/or gusts of 25 mph or greater. Both of these conditions must occur simultaneously for at least 3 hours in a 12 hour period, according to the NWS.