A chilly spring in the Puget Sound, but not quite a record

SEATTLE FORECAST:

Morning Low: 45

Afternoon High: 54 (Normal Seattle high: 64)

CLIMATE NOTE: This has been a rather chilly spring (April 1-present) across the Northwest but it is not terribly unusual to be this chilly when looking at the historical record. Since records began at Sea-Tac in 1945, this April 1-May 5 timeframe is just the 11th-coldest. Chilly for sure, but not record-breaking. What has been very unusual is that we’ve had nearly a decade of “nice springs” in Western Washington with several of the last few years having much warmer conditions with many sunny days in April and May. Simply put, we have been “spoiled” by so many warmer spring months than we should expect, our perception of what a “normal” spring is has been “reset.” We’ve snapped to cold this spring with this stubborn weather pattern in the Pacific where warmer high pressure has been stuck well offshore, while we get cool troughs of low pressure reinforced with chilly air from the Gulf of Alaska (pic attached._ When will it end? Well, for the rest of the month, the outlook is still for cooler-than-normal weather but it’s important to remember that we’re gaining more than two minutes of daylight each and every day right now. That additional sunlight is gradually increasing the overall temperature across the Northern Hemisphere. Our temperatures will moderate (they must) and eventually in the second half of May, we should be seeing many more days in the 60s (at least) with low temperatures out of the 40s and closer to 50. Folks holding off planting tomatoes ought to give it another week to ten days but probably beyond that, they can probably get them in the ground.

FORECAST: Another chilly day with the weather pattern stuck across the Northwest, with persistent low pressure from the Gulf of Alaska feeding us chilly air and occasional weather disturbances. However, into the Mother’s Day weekend we’ll have more sunshine and fewer showers, but we’ll add the outside chance of thunderstorms each day.

For tonight, we have a slim chance of a thunderstorm mainly south of Puget Sound through late evening. Otherwise, some periods of rain and mainly cloudy skies. By Saturday morning, the overall coverage of rainfall will be greatly reduced though a few areas of rain are likely around Puget Sound and at the coast. Morning temperatures will be in the 40s. It will also be blustery at times so folks heading to the Montlake Cut to watch the Windermere Cup should bundle up and prepare for breezes with the chance for rain.

The good news is that on Saturday – compared to the last two days – there will be more sunshine. This is especially true after midday Saturday. The typical “showers and sunbreaks” weather pattern will hold up for Saturday afternoon into Saturday evening. Highs will reach the low to mid 50s – ten degrees cooler than normal for this time of year.

We’ll be watching for the development of a Puget Sound Convergence Zone from late morning Saturday through Saturday evening from near Seattle north into Snohomish County. The exact location of this west-east oriented band of precipitation isn’t certain but generally from North Seattle to southern Snohomish County (extending west to central Kitsap) will be the most likely areas for development of the Convergence Zone, then it could move a little north late in the day. Under the zone, heavier rain can be expected with the possibility of small hail and lightning.

Outside of this zone, a few showers will dot the landscape but most times will be dry after mid-morning Saturday.

In the Cascades, the convergence zone could bring heavy snow above 3,500 feet to areas around Stevens Pass on Saturday afternoon and evening. There could be travel issues on US 2 at Stevens Pass if the orientation of precipitation with the Convergence Zone is just right. Travelers should keep track of conditions. Interstate 90 should remain just in rain at times or a rain-snow mix with little to no travel impact.

Sunday, Mother’s Day will be a repeat of Saturday except the atmosphere will be a little drier, so overall expect less rainfall and potentially a less active Convergence Zone Sunday afternoon though one could develop. We’ll also see more sunshine. Highs will be again in the low to mid 50s.

A few spotty showers could remain on Monday ahead of drier days Tuesday and Wednesday. Some rain looks to return Thursday through the end of next week with cooler-than-normal temperatures remaining, though moderating a bit to highs in the upper 50s in Seattle by the end of next week.

©2022 Cox Media Group