An upper level low will move up from the south along the California coast late this afternoon, and will tap into increasing mid-level moisture. Meanwhile, elevated instability will increase and this combined with a moderate to strong trigger could result in isolated to scattered thunderstorms this evening into Sunday morning, and again Sunday afternoon and evening. Given how dry fuels are, along with continued hot temperatures, lightning efficiency will be high to very high for fire starts. The National Weather Service in Medford has replaced the Fire Weather Watch with a Red Flag Warning, which is in effect from 5 PM this afternoon to 11 PM PDT Sunday. * IMPACTS. Given the prolonged stretch of very hot and very dry conditions, lightning efficiency will be high to very high for fire starts. Additionally, gusty outflow winds will allow for new and existing fires to grow rapidly out of control. * AFFECTED AREA. All of Fire Weather Zone 624. For this afternoon, scattered thunderstorms are possible roughly south of a line from Crater Lake to Summer Lake. Tonight, isolated to scattered thunderstorms could affect most of the zone. Sunday afternoon and evening, scattered thunderstorms are possible across the eastern portions of the Fremont-Winema National Forest, along the Klamath/Lake County border and eastward. * THUNDERSTORMS. Isolated to scattered thunderstorms are expected late this afternoon and tonight and again Sunday afternoon and evening. Lightning strikes outside of precipitation cores are possible and cause for concern. * OUTFLOW WINDS. Gusts up to 40 mph. These outflow winds can travel up to 50 miles away from the thunderstorm that caused it. * ADDITIONAL DETAILS. Thunderstorm activity is mainly expected during the afternoons and evenings. * DETAILED URL. View the hazard area in detail at https://www.wrh.noaa.gov/map/?wfo=mfr