The previous few days have been cooler than regular as marine air inundated the western facet of our area. But that’s going to alter over the weekend, and by Monday, Seattle might hit 90F and Portland may surge to 100F or extra. So get your followers and funky drinks prepared.
Our present cool climate has been related to an upper-level trough of low stress over the area (see 500 hPa–about 18,000 ft–map under for eight AM this morning).
But issues change over the weekend as a major ridge of excessive stress and heights builds alongside the West Coast…take a look at the identical map for Sunday at 2 PM… 180° change!
Ridging brings sinking and warming air over the area…and extra necessary than that, inland stress rises leading to offshore (easterly) movement that cuts off western Washington and Oregon from the cool, coastal air.
Let me present you the expected heat up!
The forecast floor air temperatures and winds for five PM Saturday, exhibits 80sF within the Willamette Valley and the Columbia Basin, however cooling northerly movement over Puget Sound the place temperatures solely climb into the decrease 70s. Very good day. Good one for outside exercise.
But the scenario is significantly totally different, and extra toasty, on Sunday at 5 PM. Notice the event of easterly movement over southern WA and northern OR–easterly movement quickly warms because it sinks and compresses on the western slopes of the Cascades. Our huge warmth waves all have sturdy easterly movement crossing the mountains. Portland jumps into the higher 90s, as does the Tri-Cities space.
But the true show-stopper is on Monday (5 PM proven)–the warmest day of the sequence, apart from the rapid coast. The Columbia Basin and the Willamette Valley are torrid….with vital areas above 100F. Seattle will get into the higher 80s to close 90F. But look intently and you may see cool air transferring inland from the coast.
There can be a weak marine push late Monday and Tuesday, with modest cooling west of the Cascade crest. And there can be main cooling…and the possibility of rain later within the week.