Statewide Discussion: Most of Oklahoma received much needed rainfall just over one week ago with locations did measure wetting amounts temporarily boosting live herbaceous fuel moisture. The state is now seven days (or more in some areas) separated from wetting rains with persistent, underlying drought conditions and stressed fuels on the heels of a hot, dry summer. New wildfire occurrence increased over the weekend and that trend is expected to continue through the week with warm and dry conditions. While no critical fire weather is expected through the week,
temperatures +/-10° above normal, ample daytime drying and a dry-front on Tuesday will support the expectation for increasing initial attack activity. Initial attack activity is expected to remain successful although few large fires (+300 acres) cannot be ruled. Probabilities for significant fire occurrence (+5,000 acres) remains very low.
Today: Good overnight moisture recovery will stall development of active burning conditions to some extent although above normal temperatures and afternoon relative humidity values ranging from the teens in the western Oklahoma Panhandle to around 35% further east. Overall, generally light winds will limit fire spread potential affording very good opportunity for successful initial attack.
- Western One-Third of Oklahoma: Temperature will warm into the low- to mid-90°s with afternoon relative humidity values 16-25% yielding receptive fine-dead fuel moisture of 4% at many locations. Southerly winds sustained around 10 mph with limited gusts (western Panhandle could see afternoon gusts to 17 mph) will hold fire spread potential in a manageable range. Rangeland fuels will produce head fire rates of spread +/- 65 ft/min during peak burning conditions. As a dry cold front approaches overnight, winds will increase as they begin the clockwise shift however respectable moisture recovery should offset potential for increasing fire behavior.
- Central Oklahoma (Middle 1/3rd): Temperature in the low-90°s under sunny skies with afternoon relative humidity values 25-32% will again support receptive fuels with 1-Hr. fuel moisture at 5% across the area. Light and variable winds over most of the area will limit fire spread potential although the variable nature will likely result in shifting spread direction. Grass-dominated fuels will support fire spread generally less than 50 ft/min.
- Eastern Oklahoma: Light and variable winds will serve to limit fire spread potential with slope driven fire behavior
dominating both rate of spread and spread direction. Temperature will top out in the 88°-92° range with afternoon relative humidity values 27-36% yielding fine-dead fuel moisture at 6% noting that some sites will tap 5% during the peak of the burning period. Fuels will support manageable rates of fire spread generally less than 45 ft/min., again noting that slope driven fire behavior may exhibit quicker rates of spread. While recent rainfall has set back the frequency of problematic fire behavior, firefighters should expect some single/group tree torching especially where pine/juniper species are prevalent. - Tuesday: A dry, cold front will slip into the state overnight resulting in increased wind speeds. Despite somewhat cooler temperatures, dry conditions persist as northerly winds increase prompting elevated fire weather over drier than normal fuels. Rates of fire spread will be increased over what has been experienced in recent days. Higher fire danger indices are expected across the state although the highest fire danger will develop midday along and north of I-44.
- North/West of I-44: Temperature low-70°s to low-80°s under mostly-clear skies with relative humidity values 21-26% will yield 1-Hr. fuel moisture at 5% with some 4% observations possible. North to northeast winds will be strongest early in the burning period becoming sustained 10-16 mph I the afternoon gusting 18-23 mph. Rangeland fuels will exhibit head fire rates of spread 77-115 ft/min and flame lengths around 9 ft. Brush fuels will likely exhibit problematic fire behavior including single/group tree torching and short-range spotting. While initial attack may be more challenging, efforts will remain largely successful noting that large fire probability is increased.
- South/East of I-44: Temperature 80°-90° and relative humidity values 26-36% will hold fine-dead fuel moisture above
5% with 6-7% observations likely. Northerly winds will increase into peak burning period sustained 8-15 mph with some gusts around 20 mph supporting increased fire behavior. Grass-dominated fuels will exhibit head fire rates of spread 65 95 ft/min with flame lengths +/-11 ft. Timber fuels will produce ROS nearer to 32 ft/min. Firefighters need to remain mindful of the potential for problematic fire behavior including group tree torching and short-range spotting. Short-crown runs cannot be ruled out in the pine-dominated forests where slope is aligned with wind direction.
Wednesday/Thursday: As the cold front washes out, a warming trend begins with continued dry conditions that carries through the remainder of the week. Fire weather will be strongest in the Panhandle and northwestern counties while the driest fuels reside in southwestern and south-central counties. Despite the lack of alignment between fuels and fire weather, elevated fire danger remains a concern. In general, initial attack efforts are expected to be successful with rangeland fuels supporting rates of spread during peak burning conditions averaging 72 ft/min. It should be noted that some individual fires may exhibit increased ROS when wind and slope are aligned with available fuels. - Near-Term: The current Quantitative Precipitation Forecast hold no optimism for rainfall through the next seven days. The 6-10 Day Temperature and Precipitation outlooks are equally pessimistic pointing to the likelihood of continued warmer/drier conditions. Currently no particular day or period stands out as presenting critical fire weather over dry fuels but continued drying as the growing season winds down will result in increasing wildfire occurrence trends and progression into increased likelihood of large fire emergence.
