Typical Summer Weather Across the Northwest

FastCast—Monday, June 26 to Friday, June 30:

Seasonable and pleasant summer weather is expected this week across the Northwest. In the lowlands, expect highs through Wednesday in the mid to upper 70s, increasing to the upper 70s to low 80s for Thursday and Friday. Conditions will be partly cloudy on Monday and Tuesday, becoming sunnier for the rest of the week. Morning marine clouds are likely most days, though some spots may escape morning clouds. Clouds will become less prominent by mid to late week. All week, expect overnight lows in the low to mid 50s. Additionally, there is a chance of thunderstorms on Monday and Tuesday in the Cascades and Eastern Washington. Any areas that are impacted by isolated thunderstorms may experience frequent lightning, heavy rain, small hail, gusty winds, and a chance of flooding. Forecasts are beginning to show warmer weather toward the beginning of July, so stay tuned!

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Continue reading the full blog below!

Typical summer weather is ahead for the Northwest, with the added feature of a chance of thunderstorms from the Cascades eastward to start the week. Let’s take a look at the forecast!

First, the NAM high-resolution forecast for highs on Monday, seen below.

Across the lowlands, expect highs in the low to mid 70s. The coast will remain cloudy, with highs in the mid to upper 50s, and Eastern Washington will be on the hotter side, with highs in the mid 80s to low 90s.

Next, let’s take a look at Tuesday’s highs, seen below in the European model forecast.

On Tuesday, expect highs in the mid to upper 70s in the lowlands (except in the low 70s near the water) and still in the mid to upper 50s on the coast. Eastern Washington will remain warm, with highs in the mid 80s to low 90s.

Now, let’s take a look at precipitation through late Tuesday, also on the European model.

Notice that the lowlands receive no precipitation through late Tuesday. There will be light drizzle (trace to 0.1”) on the coast, but the most precipitation will be in the Cascades, Olympics, and Blue Mountains, where afternoon thunderstorms will bring areas of rain, heavy at times. The strongest storms will bring a chance of flooding in the mountains.

Now, let’s take a look at the NWS Storm Prediction Center (SPC) outlooks for Monday and Tuesday. 

Monday’s outlook is below.

There is a chance of thunderstorms for all areas west of the Cascade foothills on Monday, including most of the Pacific Northwest east of the Cascades.

On Tuesday, a similar situation will play out, as seen below.

Tuesday’s outlook is nearly identical to Monday’s, except the chance of thunderstorms encroaches a little bit closer to Western Washington, mainly from Snohomish County northward. 

Finally, let’s take a look at the extended forecast outlooks from the NWS Climate Prediction Center (CPC), showing trends for temperature and precipitation.

First, the CPC temperature outlook for July 1-5.

There is a 50-80% probability of above average temperatures across Washington for the first 5 days of July. This is part of the signal for a warmer beginning of July that I mentioned in the FastCast.

Next, let’s take a look at the CPC precipitation outlook, also for July 1-5.

The entire state of Washington has a 33-60% probability of below average precipitation, with a 50-60% probability bullseye from Seattle to the coast and from the Columbia River to the Strait of Juan de Fuca.

Enjoy the pleasant weather, and watch for mountain thunderstorm clouds!