August fire weather, typically, and this year

Today we have another article from Incident Meteorologist Chip Redmond.


2014 August fire weather

Typical fire season for August is focused greatly on the western US and Pacific NW. This time of year a summer upper level ridge is usually prevalent across the western US. This leads to hot and dry conditions reaching into Canada. However, monsoonal rains creep northward into much of the inter-mountain west from Mexico bringing a break to fire season in much of Colorado, Arizona, California, Utah and other nearby states. These monsoonal rains are the wet season for many, and besides the winter snows, are a large source of water.

August fires
Monthly Fire Occurrence Density in August. From Predictive Services (1999-2010 data).

In the recent weeks, we have seen quite a bit of large fire activity in Washington, Oregon, and California. For this time of the year, it is fairly typical to expect hot spots in these regions. However, the size and vigor of these fires has been greatly magnified with already a record fire season (Carlton Complex). The main driver of these impressive fires has been the significant drought impacting the western US, which has been developing over the previous years. Despite some recent rains in many areas, especially inter-mountain West (thanks to seasonal monsoonal moisture), much of it has fallen to the east of the greatest Exceptional Drought. This drought has substantial impacts on both short and long term vegetation and fuel conditions. It has made the region very susceptible to very large fires with extreme fire behavior.

Drought Monitor as of 7/29/14
Drought Monitor as of 7/29/14

The big question is, will these conditions continue? Long-term it appears that they will. This persistent pattern is showing signs of weakening short term, but after this weekend, forecast models hint at more prolonged ridging much like we have had the previous weeks. A very active Western Pacific typhoon season is somewhat to blame. As systems move north, and eventually northeast past Japan, they amplify the large upper level ridge assisting in the continued hot and dry weather for the western US. With numerous typhoons still across the western Pacific, it appears this may continue to occur. Long-term models also suggest continued below normal rainfall and above normal temperatures for the next 1-3 months for the W US. There is some suggestion of El Nino development this fall which could bring some much needed relief to portions of southern California. However, should it develop, it would also suggest warmer than normal conditions across regions of Washington and Oregon.

It appears that it likely be a very long, and dragged out fire season for many in WA, OR, and CA.

Typos, let us know HERE, and specify which article. Please read the commenting rules before you post a comment.