The “weather whiplash” or “May weather mayhem” continues with temperatures more than 20 degrees cooler on Friday compared to Thursday, which ended with thousands of lightning strikes in an eruption of severe thunderstorms in central Washington.
While the month of May will (as expected) wind up a little warmer and drier than average — and June is expected to follow suit — the swings in temperature have been stark this month.
The last weekend of May will be cool, but with some sunshine. The average high for Saturday and Sunday in Seattle is 69°, and we’ll likely stay just shy of those temperatures.
However, another ridge of high pressure aloft builds early next week to start the month of June. This will allow for plenty of sunshine (high pressure aloft often promotes sinking air, which inhibits cloud formation) and we’ll see offshore wind flow develop which turns off “nature’s air conditioning” which is the cool onshore, or west-to-east wind flow off the Pacific.
Highs in Seattle Monday will reach well into the 70s and I’m forecasting the warmest temperature of the year so far on Tuesday at 84°. It’s possible we get even a little warmer than that under the right conditions, and there will be some of the hottest foothill and southern Washington communities that hit 90° on Tuesday!
(The record high for Seattle on Tuesday, June 2 is 94° set in 1970. That record is safe.)
While heat stress could build briefly for those without air conditioning, the onshore cooling wind flow will kick back in starting Wednesday for some relief, and there could be some rain chances with cooler days later in the week.
However, with these warm days ahead, be careful with anything that could start a fire. While our forested areas aren’t quite yet in their prime time for wildfire we see in the summer months (though anything will burn under the right circumstances), brown grasses on either side of the mountains will readily burn.
We’ll be updating the forecast for the early June heat on KIRO 7 all weekend!
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