Major Alter Inwards Northwest Weather: Pelting Moves In, Smoke Moves Out

A potent upper score trough volition deed inland over the percentage this evening as well as tomorrow morn bringing cooling weather, clouds, about precipitation, as well as the removable of the smoke layer aloft.

To start,  hither are the upper-level (500-hPa, nigh 18,000 ft) charts for the side yesteryear side few days.

This morning  (5 AM) shows a big ridge over the western U.S., only a potent unopen low/trough offshore.

Tomorrow morn at v AM, the trough/low is moving into our coast.

The trough moves through on Sabbatum as well as therefore moves northeastward into Canada on sun (11 PM sun is shown below)

The initial approach of the trough is associated amongst enhanced southerly stream that brought upward smoke from California, only every bit it passes, the winds volition plow to a greater extent than westerly, driving the smoke to the east.  This progression is shown yesteryear the HRRR-SMOKE model output. This morn at 10 AM, in that place was fairly dense smoke aloft (see figure), only far less at the surface.

But yesteryear 2 AM, western Washington is clear, every bit the densest smoke moves over eastern WA as well as Idaho.

 Precipitation should offset moving inwards yesteryear v AM, illustrated yesteryear the UW WRF model atmospheric precipitation for the 3-h stream ending that time.

 Heavier pelting is predicted during the subsequent 3 hours, especially along the coast, the Olympics, as well as SW Washington.

The showers deed to the Cascades during the afternoon.

  And proceed spell like shooting fish in a barrel declining during Sabbatum evening.

Seattle volition non got a lot from this effect as well as nosotros create await about embedded thunderstorms.   Sunday should endure dry out as well as warmer (around 80F).

Finally, it is interesting to aspect dorsum at the temperatures at Seattle Tacoma Airport during the terminal 12 weeks compared to the normal highs (purple) as well as normal lows (cyan).  We select had a serial of oestrus waves during the yesteryear 2 months, amongst about intervening cool periods.

Clearly, this summertime was warmer than normal, something shown graphically amongst the next map of the temperature differences from normal over the yesteryear lx days.  Western WA has been 1-3F higher upward normal, amongst California beingness fifty-fifty warmer (perhaps 3-4F higher upward normal for the period).