UPDATE | 8/13/14, 5AM: According to weather forecasters, the thunderstorms that hit areas of Eastern WA Tuesday afternoon and evening lost steam as they came off the Cascades, only bringing rain shower (some heavy) to Western WA. SeaTac Airport picked up just over an inch of rain since 12AM. North Bend got just over a half inch.
Factoria Blvd near I-90 was closed temporarily due to urban flooding when the area experienced heavy rain in a short time period very early Wednesday morning.
The fire and thunderstorm threat has ended. Showers, some heavy, are likely for Wednesday morning, decreasing as the day progresses. By Friday the Snoqualmie Valley is expected to transition back to more dry, summer like conditions.
According to local weather forecasters, more widespread rain and thunderstorms was marching toward Seattle, Tacoma and Eastside areas Tuesday afternoon, August 12, 2014.
After an active weather Monday night, most of Tuesday had been fairly calm, with predicted thunderstorms missing the Snoqualmie Valley and picking on the southwest Washington coastal areas.
But local weather forecasters say that has changed as the clouds cleared and the temperatures jumped up. In Seattle it went from 71 to 81 degrees in one hour Tuesday afternoon, triggering a fairly rapid formation for thunderstorms in southern Washington – ones that were heading north.
The National Weather Service (NWS) extended the Red Flag Fire Warning for Western Washington in response, which now runs through 11PM, Tuesday, August 12th. The warning was originally due to expire at 5PM. A rare severe thunderstorm watch was also issued for areas southwest Washington and northwest Oregon.
A red flag warning means that critical fire weather conditions are occurring now or will shortly. Strong winds, low humidity and warm temperatures can all contribute to extreme fire behavior.
NWS stated that low pressure over Northern California will merge with another low coming down from the Gulf of Alaska “resulting in sufficient moisture and instability to continue the threat for thunderstorms over much of Western Washington this evening and tonight [August 12, 2014].”
According to Cliff Mass Weather Blog, the southern Cascade Mountains were experiencing multiple lightning strikes Tuesday afternoon as the storms fired up.
Those with outdoor plans Tuesday afternoon and evening are advised to monitor weather conditions and seek shelter if they hear thunder. Some storm cells could bring frequent lightning, strong winds, rain and small hail.
The thunderstorms will transition to just plain rain showers overnight as the atmosphere stabilizes. To see pictures of Monday night’s lightning visit our earlier story HERE