Rain During the Driest Time of the Year

Seattle this AM.  Some wildfire smoke is evident on the horizon.

Late July and early August are climatologically the driest time of the year (see below) and mother nature is follow the typical game plan.  Here in Seattle it hasn't rained since July 22nd!

But our run of dry days is going to end for most of western Washington tomorrow, as the first weak front of Augusts moves through and the temperature change will be chilling.

The latest infrared satellite picture shows the weak front poised to move in tonight and tomorrow morning.  Yes, we have seen more impressive fronts, but this is August!

The UW high resolution WRF forecast 24-h precipitation total ending 5 AM Friday morning indicates the wettest conditions will be on the western slopes of the Cascades, northwest Washington, and southern BC.  A weak convergence zone is expected over northern Puget Sound.

But what will get your attention will be the temperature change, with highs going from around 80F earlier  this week down to the upper 60s in western WA.  To illustrate, here are the predicted temperatures at 5 PM today and on Thursday.  Profound cooling on BOTH sides of the Cascades.  Obviously, good news on the wildfire front, with dropping temperature and increasing humidity facilitating the control of the handful of fires burning in Washington and Oregon.  Really important to get this break.

The only negative will be a surge of the winds tonight and tomorrow morning, which can stoke the fires--something firefighters will have to watch.

The extended forecasts are quite benign, with no heat wave in the offering.  The European Center forecasts for SeaTac Airport show temperatures warming back up to around 80F on Sunday and Monday, followed by another weak/wet front and cooler temperatures late on Tuesday and Wednesday.  Exactly what is needed to ensure our temperatures mild and keep the wildfire threat in check.

Image courtesy of weatherbell, inc.

  Mild temperatures are good for dealing with COVID, reducing the need to retreat to interior air conditioned spaces and making safe, outdoor eating optimal.   As I noted in several blogs,  there is little evidence of effective transmission of COVID-19 outdoors.  This is a very robust conclusion.