VERY HOT, DRY, AND UNSTABLE CONDITIONS CONTINUE TODAY. A strong ridge of high pressure will remain over the area producing hot dry and unstable conditions especially to eastern portions of central Oregon. A weak weather disturbance will move up the coast helping to trigger isolated to scattered thunderstorms in central Oregon today through evening. * AFFECTED AREA. Fire Weather Zones 611 Deschutes National Forest -minus Sisters Ranger District and 640 Central Mountains of Oregon. * TIMING. Noon to 10 PM Sunday. * RELATIVE HUMIDITY. As low as 10 percent. * TEMPERATURES. Up to 100. * THUNDERSTORMS. Isolated to widely scattered. Lightning activity level of 2 to 3. * OUTFLOW WINDS. 35 to 45 mph. Thunderstorm outflow winds may result in erratic fire spread. * IMPACTS. Any lightning strikes combined with hot and dry conditions could cause new fire starts.