Last night and this morning, a front moved through bringing heavy rain and gusts of wind. As shown by Saturday’s steam image (below (, this front is mining into a giant plume of steam thousands of miles across the Pacific Ocean that has been around for weeks).
The main feature of our cool, cloudy weather problem is the existence of a persistent low pressure area over the Gulf of Alaska (see upper – 500 hPa / about 18,000 ft– map for today at 5 a.m. below, temperature at level shown in shadow, warmer orange/red).
With low pressure over the Gulf of Alaska and higher pressure in the subtropics, the result is a large change in pressure, resulting in a strong jet stream to the west. Bring in moisture from the west. The atmosphere is really like a big Rube Goldberg machine!
Fortunately, there will be a significant break Tuesday afternoon as a high pressure peak forms modestly in the area (see upper-level map below, with arrows indicating high pressure peak). You notice that the tongue of warm air is moving north on the West Coast.
According to the National Weather Service’s flagship forecasting aid, the National Blend of Models, temperatures at SeaTac could be surge to 71F on Tuesday… imagine that! Before falling back to the 60s.
The big deal is that our old friend, the Gulf of Alaska Trench, will rebuild, leading to an even wetter system over the weekend (above 5 a.m. map next Saturday is shown).
This is getting very old. The UW WRF model’s 48-hour total precipitation ending at 5 p.m. Saturday shows heavy rain in the mountains (orange to red) and moderate rain elsewhere.
Controversial Note:
Less controversial note:
I will be giving talks and book signings at the Northgate Barnes and Noble in Seattle at 1:00 p.m. Saturday, June 25.
