September 3, 2020 – The official Predictive Services outlook calls for drier and warmer than average conditions in the North Ops region through December. The above normal cured fine fuel crop will be vulnerable to rapid spread rates and extreme fire behavior during dry breezy weather patterns, which will increase in frequency starting in mid September. Lightning will be less common in September than it was in July and August, but any lightning will pose a high risk of causing new large fires.
The main risk areas for lightning fires are the northern and eastern mountains, above 3000 ft. All areas have Above Normal Significant Fire Potential in September. In October the focus for Above Normal Significant Fire Potential is on areas from the western Cascade Sierra slopes to the coast.
Areas not mentioned above have “Normal” significant fire potential in October, and all areas return to Normal in November and December. However, there is a chance that fall rains may not arrive until early to mid November, and in that case the
Above Normal areas in October will continue to be above normal in November. In September “Normal Significant Fire Activity” is defined as 1-3 large fires per PSA. In October “Normal” is defined as 1.2 or fewer large fires per PSA. All PSAs average below 1 large fire in November and December.
As September begins there are signs that the larger-scale late summer pattern shift is beginning to take place. With this pattern change we see less threat from thunderstorms, and dry cold fronts followed by a period of gusty N-NE foehn winds become more frequent. These fronts and the foehn winds become stronger late in September. In the tropical eastern Pacific the ENSO status remains neutral, but a gradual trend toward a weak La Niña event is expected late this fall and winter. This could lead to warmer and drier than average weather through the end of 2020.
- Live and dead fuels of all size classes are near average to drier than average, with further drying expected in early Sept.
- Above normal loading of cured fine fuels below 3000 ft el.
- Warmer and drier than average weather through December
- Lightning, when it develops, still poses a threat of large fires
- N-NE/Offshore wind events will become more frequent and more intense in Sept, and pose a high risk of large fires
- Above Normal all areas in September
- Above Normal Wrn Cascade-Sierra slopes to the Coast in October
- Normal Significant Fire Potential all areas in November and December