Unsettled Pattern Continues & A Potential Change Upcoming

FastCast—Thursday, Apr. 20 to Monday, Apr. 24:

After a few days of showers and chilly conditions, an unsettled pattern will continue through early next week across the Northwest. Another round of rain will move in from Thursday afternoon through early Friday, with showers at times from Friday through Saturday, followed by another round of rain from midday Saturday through early Monday morning. Across the lowlands, expect 0.25-0.75” of rain through Friday, with more this weekend (another 0.4-0.8”). The coast will get 0.75-1” through Friday, with another 0.5-1.5” through the weekend. Temperatures through Monday will still be below average, but will warm some from the first half of this week. Generally, expect highs in the low to mid 50s, except near the upper 50s to around 60º on Saturday. Lows will drop to the mid 30s on Thursday morning (isolated areas in the low 30s with frost possible) and then will stay in the low to mid 40s through Monday morning, except in the upper 40s on Sunday morning. Forecasts show a potential for a significant warm-up with sunnier weather next week. Details are far from certain and changes are expected, so stay tuned.

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Continue reading the full blog below!

This April has been defined by below average temperatures and many showers, and that will continue. Another round of rain is ahead from midday Thursday through early Friday morning, with showers at times through Friday. Below is the European model forecast for total rain through Friday night.

Across the lowlands, expect 0.25-0.75” of rain, with higher amounts under heavier showers. Areas from Olympia south will get 0.4-0.8”, and the coast will get 0.5-1.25”. Eastern Washington will pick up a trace to 0.4”, most near the Idaho border.

Temperatures will remain on the chilly side, especially Thursday morning. Take a look at the European model’s forecast for Thursday morning lows.

Most of the lowlands will drop into the mid 30s, with areas near the foothills dropping into the low 30s. The coast will reach the mid to upper 30s, and Eastern Washington will be quite chilly, dropping into the mid 20s to mid 30s, warmest in the lower Columbia Basin.

High temperatures on Thursday will be significantly below average across the lowlands, as seen in the European model forecast below.

Expect lowland highs only in the upper 40s to low 50s, far below normal. Even Eastern Washington will only reach the upper 40s to mid 50s.

The NWS Climate Prediction Center (CPC) outlooks for April 25-29 do show a change. 

Let’s start with the temperature outlook below.

This outlook shows a 33-50% probability of above average temperatures for Washington, consistent with extended forecasts that are also showing a warmup.

Next, the precipitation outlook, also for April 25-29.

This outlook shows a 33-50% probability of below average precipitation to end April across the state. Overall, extended forecasts are pointing to a warm-up with less rain by next week. 

However, this same pattern has appeared in extended forecasts over the past month, only to disappear from those same forecasts a few days later, due to the placement of high pressure ridges. A potential warmup still needs monitoring, so stay tuned!