'Fire Weather Watch' issued as lightning threat looms

SEATTLE -- Our recent stretch of sunny, warm weather is great for summer outdoor fun, but our dry stretch has increased the wildfire danger here and now there is growing concern that thunderstorms this weekend could spark new rounds of wildfires -- even in parts of Western Washington.

So the National Weather Service wants to alert local and regional firefighters to the potential danger by issuing a "Fire Weather Watch" for the eastern Puget Sound lowlands east of I-5, as well as for much of Southwestern Washington and the Cascades.

The watch will remain in effect from Friday afternoon through Sunday evening.

A Fire Weather Watch is a precursor to a possible Red Flag Warning, which is the top rung on the fire weather warning list -- similar to how in the winter, a High Wind Watch comes first when a storm has potential, and then a High Wind Warning is issued if it's happening or imminent.

A Red Flag Warning is issued when for the combination of dry fuels and incoming weather that would be an aggravating factor to creating wildfires, be it dry humidity, lightning, and/or strong winds that would help quickly spread any wildfire.

In this particular case, it's lightning that is the biggest threat.

An approaching area of low pressure from California will bring unstable air to our region, starting to the south Friday afternoon, then spreading across the area Friday night. As the low continues its slow approach to the Washington Coast for Sunday, conditions will be ripe for thunderstorm development over the Cascades and Olympics during the entire period.

Meanwhile, upper level winds are expected to be out of the east/southeast that could push thunderstorms off the Cascades into the lowlands - especially the foothills and, particularly on Friday night, Southwestern Washington. This overall pattern would be a somewhat similar situation to the thunderstorms that roamed across our region last Wednesday.

The threat for the lowlands abates Sunday night as the low moves away.

Luckily we don't have an east wind situation which gives very low humidity and adds strong wind to the equation. But the lightning along is worth the worry and individual thunderstorm cells can bring gusty, erratic winds to new or any existing fires.

These fire weather watches are intended mostly as a heads up for the firefighting community, giving fire companies a heads up that they might be very busy this weekend.

"It's time to have all hands on deck," said Andy Haner with the National Weather Service.

For the public, it serves as a reminder of how dry conditions are and to be particularly careful with anything that could spark a fire.