Below Average Temperatures Continue & Atmospheric River Recap

FastCast—Sunday, June 12 to Thursday, June 16:

After a major June atmospheric river on Thursday and Friday and a beautiful day on Saturday, a return to much below average temperatures is in store for Sunday and Monday. Temperatures will only reach the upper 50s to low 60s, with lows in the upper 40s. There is a chance of showers on Sunday and Monday, including multiple Convergence Zone bands. Expect around 0.1-0.15 inches of rain in showers, except up to 0.5” under the Convergence Zone (likely around Everett). Temperatures will begin warming up on Tuesday, with highs reaching the low to mid 60s. Wednesday and Thursday will be even warmer (but still below average), with highs reaching the mid to upper 60s. Lows will be in the upper 40s to low 50s. Tuesday through Thursday will be partly to mostly cloudy, with no rain.

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Continue reading the full blog below!

Our trend this spring has been below average temperatures, and that will likely continue. The graphic below shows the probability of above or below average temperatures, from the NWS Climate Prediction Center through Pivotal Weather.

The bullseye for below average temperatures is the Western US, especially the Pacific Northwest. 

So how chilly will it be? Take a look at Sunday’s highs from the NAM model.

High temperatures in the lowlands will only reach the mid 50s to low 60s. With average highs around 70 degrees for the lowlands at this time of year, that means that highs on Sunday and Monday will be 10-15 degrees below average.

This trend will spread around the entire Pacific Northwest, with high temperatures significantly below average, especially in the Inland Northwest. The European model forecast is below for temperature anomalies on Monday.

Temperatures will be significantly below average. The Lowlands will be 5-10 degrees below average, and areas east of the Cascades and in the Western Foothills of the Rockies will be a whopping 20 to 40 degrees below average. For example, Boise’s high on Monday will be in the upper 50s to low 60s, while average highs are typically in the upper 70s to low 80s. 

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Atmospheric River Recap:

What an event! This atmospheric river was more on-par with an AR expected in fall or winter. The NWS precipitation analysis below shows the total precipitation recorded for the event.

The lowlands from Seattle southward received 1-2 inches of rain, with similar amounts around Portland and on the coast. The mountains of WA & OR received up to 6 inches! Many areas west of the Cascades received their entire month’s worth of rainfall in less than 3 days!

As expected, this rain brought rises on area rivers, with some getting close to flood stage. I took this photo at Snoqualmie Falls on Friday morning.

The flow at the Falls was similar to fall and winter flood events, but in June. This image sums up our wetter and cooler than normal spring.