Statewide Discussion: Oklahoma remained dry through the week other than southeastern Oklahoma where Francine pushed some wetting rains into the far southeastern counties. The pockets of extreme drought increased in coverage while severe drought indices ramped up nearly 10% focused in southwestern and southern tier counties as the days since wetting rain continue to increase. The lack of rainfall has exacerbated soil moisture resulting in increased fuel availability. Locally moderate initial attack activity has remained largely successful lacking full alignment in the fire environment. While we return to summertime heat though the weekend, fire weather will fall below critical concern with windspeeds generally 12 mph or less, good overnight moisture recovery and moderate afternoon relative humidity values. Initial attack efforts are expected to remain successful with low probabilities of large fire occurrence.
Today: Based on forecast data, today has the strongest combination of fire weather through the weekend. The highest fire danger indices continue to reside in the southwestern counties noting that the wheatbelt counties are now nearing a month without wetting rains. Additionally, the Panhandle counties will see relative humidity values fall into the teens this afternoon enhancing fine-fuel receptiveness.
- Southwestern Oklahoma: Temperature this afternoon in the mid- to upper-90°s with relative humidity values 27-33%
under clear skies will yield fine-dead fuel moisture values at 5% – improved over recent days. South winds this afternoon sustained 8-12 mph with some higher gusts will support head fire rates of spread in rangeland fuels +/- 75 ft/min and flame lengths +/-8 ft. Relative humidity values begin to improve after sunset with very good overnight moisture recovery anticipated. - Northwestern/Oklahoma Panhandle: Most locations are now nearing two weeks since a wetting rain and increasing
fuels availability. Temperature will climb into the mid- to upper-90°s later today with relative humidity values 15% in the western Panhandle to around 30% in the northwestern counties yielding fine-dead fuel moisture values 3-5% during peak burning conditions. Southwest to south winds sustained 9-14 mph with some higher gusts will support moderate rates of fire spread in rangeland fuels. Head fire ROS 50-85 ft/min with avg. flame lengths +/- 8 ft should be expected on fullyestablished wildfires. Very good overnight moisture recovery will support very good initial attack success probabilities. - Central/Eastern Oklahoma: Initial attack activity has increased some and that trend will continue into the weekend.
Today, temperature in the low-90°s and afternoon relative humidity 29-36% will yield find-dead fuel moisture 5-6%.
Variable winds will limit fire spread potential holding rates of spread generally less than 65 ft/min. Additionally, herbaceous live fuel moisture will serve as a heat sink in many areas further limiting spread potential offering very good opportunity for initial attack success.
Saturday: The highest fire danger indices will remain in southwestern Oklahoma noting that somewhat more moist air will limit relative humidity values from falling below 25% excluding the far western Panhandle where observations around 20% are expected. Temperatures will approach 100° in southwestern Oklahoma while low-90°s are expected elsewhere. Generally, southeasterly winds less than 10 mph will also limit fire spread potential in grass-dominated fuels affording good initial attack opportunity. It is worth noting that there is a very slim chance for isolated thunderstorms to develop in far western Oklahoma.
While the chances are very low, lightning ignition and storm influenced winds could prove problematic to fire behavior on any active fire in the vicinity of a storm.
Sunday: Good overnight moisture recovery will stall development of the active burning period. Temperatures approaching 100° in the southwest and afternoon relative humidity values +/- 25% will hold the highest fire danger indices again over the southwestern counties. Southeast to easterly winds will hold fire spread potential below 80 ft/min continuing the expectation of initial attack success. Central and eastern Oklahoma should not see relative humidity values dip much below 40% reducing probability of ignition from previous days.
Near-Term: The current Quantitative Precipitation Forecast does not hold potential for widespread wetting rains, although a bit more active weather pattern early next week does prompt some rain chances with the best opportunities in western and northern Oklahoma Tuesday through Thursday.
