Warmest days of year likely this week in Western Washington

All signs point to much warmer weather heading to Western Washington this week, with many spots getting into the 70s for only the second time this year!

Textbook setup for warmer weather

The weather pattern changes quickly by Monday with high pressure aloft strengthening over the West Coast.

Ingredient Number 1: High pressure aloft causes slowly sinking air which helps to eliminate daytime cloud cover and bring more sunshine and warmer temperatures.  There will probably be some early morning cloudiness and possibly some patchy fog in the more prone locations like river valleys, especially early in the week.  But that clears quickly with warming sunshine.

Ingredient Number 2: A weak to moderate offshore flow sets up as we head through toward mid-week, and it will could get a bit breezy near the Cascade foothills at times.  This offshore flow -- with wind blowing from east to west -- is a reversal of the normal onshore wind flow that brings moisture and rain off the Pacific Ocean. This offshore flow brings drier air and also some natural warming as the air currents descend out of the Cascades into the lowlands.

Ingredient Number 3: Add sunshine (we're still gaining more than three minutes of daylight per day.)

Just stir!

So how warm are we talking?

High temperatures on Monday will likely be in the 60s for many low elevation locations around Western Washington, including Puget Sound and Seattle.  A few of the warmest spots in the South Sound nearer the Cascades could hit 70.

The warmest days look to be Tuesday through Thursday with Thursday probably being the peak before the onshore flow resumes and some clouds and rain come back by next weekend.

Tuesday: Probably low 70s in Seattle, upper 60s for Everett north and even mid 70s for the South Sound.

Wednesday: Probably similar or perhaps a couple degrees cooler with a few passing clouds.

Thursday: Looking quite warm with the early outlook for low to mid 70s for the central and north Sound, including Everett and Seattle with mid or upper 70s for the South Sound.  It's important to note that forecast details are much more iffy when you get close to a week out, but the overall pattern and forecast information support this type of warmth!

So, could somebody hit 80 degrees next week?  It's definitely possible, so stay tuned!  The KIRO 7 Pinpoint Weather App (kiro7apps.com) will have our updated Seattle-area forecast.

How long has it been since we were in the 70s?

Seems like forever, right?

But back on March 12, a one-day burst of warmth sent Seattle to 73 degrees, setting a new record high.

While the normal high temperature for Seattle next week is 60 degrees, the record highs are up in the upper 70s or lower 80s for Seattle.  Unlikely to break those, but possible.

What is certain is that this will be the warmest April weather for most or all Western Washington since 2016!  Why?  Seattle did not have a single 70 degree day in April of last year!

KIRO 7 Pinpoint Chief Meteorologist Morgan Palmer will have the updated hour-by-hour forecast for the weekend and track next week's warm spell on KIRO 7 News at 5, 6, 7 and 11 p.m. 

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