Sure, there has been practically no sun along the coast. Yes, Seattle has had a record-breaking stretch of morning clouds. Sure, most days have not come close to the normal afternoon highs.
But things are going to change, so stock up on ice cream, get some ice ready, and put away those sweaters.
Heat is on the way.
The reason for the change? A substantial change in the large-scale organization of the atmosphere over the eastern Pacific. Earlier in the week am upper-level trough of low pressure was over the Northwest (see graphic) and ridging (high pressure) was well offshore.
The new situation is for the ridge to amplify and move eastward, with no trough dampening our days (next map).
With the amplifying upper level ridge, we will see increased offshore flow and the northward development of the west coast thermally induced trough (TINT). (I have a student working on this feature and we struggled to find a good acronym that was suitable for a family friendly web site).
Want to see the development of the thermal trough? Here is a series of maps with surface winds, sea level pressure, and lower atmospheric temperatures.
Thursday at 5 PM-thermal trough extending into southern Oregon!
Friday at 5 PM thermal trough into southern WA. Note the easterly offshore flow on the WA cascades
Saturday at 5 PM. Thermal trough into NW Washington. Offshore flow moving offshore. No clouds on the WA coast! AMAZING!
Sunday at 5 PM. Thermal trough even stronger and temps warmer still!Tomorrow will be beautiful and near 80F, Friday in the mid 80s, Saturday and Sunday can see upper 80s to lower 90s. The Willamette Valley will be much warmer. Why? Far less influence of marine air in that enclosed valley.
