WeatherWatcher: Excessive heat watch in effect Saturday - Monday

 

Sunny day in Shoreline on 185th near Aurora Ave. March 2019
Photo by Carl Dinse

The National Weather Service in Seattle has issued an excessive heat watch to be in effect from Saturday afternoon until Monday afternoon. This is expected to turn into a heat advisory as we get closer to the weekend.

High pressure has built up in the upper atmosphere along the west coast interior, centered over interior British Columbia, Canada. This "heat dome" or dome of high pressure is pushing sinking heating air south and west into the Puget Sound region. This brings us glorious sunny weather, clear skies, and warm temperatures.

The sunny skies and warm air are making up for our unusually cold spring. Thursday and Friday high temperatures are expected to be in the mid 70's. We could even get near or just past 80°F on Friday and into the low to mid 80's on Saturday.

Sunday and Monday are when the heat starts to crank up, with high temperatures into the mid to upper 80's, or low 90's. There's a higher chance of seeing 90°F or more if you're south of Northgate, or away from Puget Sound. I expect most of Shoreline and Lake Forest Park to be in the upper 80's to near 90°F.  Lake Forest Park might trend warmer.

At the tail end of this heatwave, as with most heat waves around here that end quickly, there is a slight chance of thunderstorms developing. An upper-level low over California might rotate some extra energy from the east up and over the Cascade Mountains. This could be enough energy combined with the cooling atmosphere to get convection started, leading to possible thunderstorm activity.

One of the dangers of this heat wave is it may drive a lot of people to go to the water. Water temperatures are still dangerously cold right now which will put a lot of people at risk of hypothermia if they spend time in the water.

If SeaTac reaches 90°F this weekend or Monday it could set the record for earliest day in the year breaking the 90°F mark. 

Beyond the weekend: Mostly sunny conditions are expected to continue through all next week, highs in the mid 70's and lows in the upper 50's. It's going to feel like summer for a while, outside of this heatwave it's probably welcomed by many after this cold and grey spring we've been having.

For current weather conditions visit www.shorelineweather.com