Record warmth, severe thunderstorms forecast for western Washington this week
WASHINGTON STATE — March is flipping the script on the old “in like a lion, out like a lamb” adage this year as our weather is about to start roaring as we close down the month.
The atmospheric pendulum will be swinging wildly over the top of us in the week to come, and we’ll need to be especially weather-aware over the next two days.
The first twist will be a surge of warm air coming up the west coast courtesy of a thermal trough in California. This warm, dry feature tends to bring on record temperatures, and it will do so on Tuesday.
Highs will reach well into the low 70s around the Central Sound, with afternoon readings closer to 80 near the Oregon state line. Our record at Sea-Tac that day is only 64 degrees, so highs near 70 will easily give us a new mark in the almanac for March 25th.
CLICK HERE FOR THE FULL FORECAST
The unusual warmth will lay the groundwork for a thunderstorm outbreak on Wednesday. Thunderstorms require moisture and lift to get going, and we get those smaller cells frequently enough around here. But we don’t often get a front seat to SEVERE thunderstorms, which require a quickly changing temperature profile in the atmosphere that includes very warm air at the surface and very cold air up aloft.
Those atmospheric dynamics will be in place around the Pacific Northwest on Wednesday, and the forecasting models look unstable enough to get the attention of the National Weather Service’s Storm Prediction Center. The agency has issued a “marginal” chance for isolated severe thunderstorms in Washington and Oregon on Wednesday, which could include not only heavy downpours, but large (dime to quarter-sized) hail, downburst winds of 40 to 60 mph, and numerous and dangerous cloud to ground lightning strikes. Conditions will even be ripe for a stray funnel cloud or two across our corner of the country.
At this point, the thunderstorms will trigger first at the ocean beaches by mid-afternoon, then will work their way up the I-5 corridor from south to north as the evening commute is underway. A few separate squall lines may come through before the heavy showers taper off after midnight.
We don’t often have to worry about lightning safety in our region, but it will be necessary to practice the “when thunder roars, head indoors!” motto Wednesday night. Those with outdoor activities on Wednesday will need to monitor the skies for quickly changing conditions. In particular, sports teams with outdoor practices should carefully monitor the KOMO weather app to track the showers and should have a plan to get the athletes safely indoors as the thunderstorms erupt. Riding out the storm in a baseball dugout or beneath trees is extra dangerous; getting inside cars is okay, but safely moving indoors and away from windows is recommended.
A secondary wave of steady rain and gusty wind will roll in by Thursday.
