Satellite pictures this morning shows a large closed low off the southern Oregon coast with the strong ridge of high pressure centered over Southern Idaho. After yesterday’s official high of 103 degrees, expect the scorching heat to continue today with high temperatures once again between 100 and 105 degrees. An excessive heat warning continues until 8:00 tonight. The atmosphere will become dry and unstable this afternoon so ongoing or new fires could become quite active. A red flag warning remains in effect until Friday morning at 10:00. Smoke filled skies has also prompted an air quality alert that will continue until Monday morning and maybe longer.
By tonight, the upper low advances towards Northcentral Washington with increasing lift and instability in the mid-levels of the atmosphere bringing us a 20% chance of showers and thunderstorms. The storm environment could lead to high based thunderstorms producing little rainfall, and moving north at 50 to 65 mph further limiting rain potential reaching the surface. Fire concerns involve gusty winds and lightning as these storm cells move through tonight and into early Saturday morning.
The elevated moisture/instability tracks out of the region by noon Saturday as a dry slot associated with the upper low overtakes the region. Cold air advection will bring about 20 degrees of cooling to start our weekend but, still warm with high temperatures in the low to mid 80’s. It will be a bit breezy Saturday as well with west winds 10-20 mph gusting to 25 mph. Sunday will be a quiet weather day with light wind and sunny skies high temperatures will climb into the mid 80’s.
On Monday and through the rest of next week its back to the heat as weak high pressure begins to build under a weak west to northwest flow aloft. This will lead to slowly increasing temperatures and mostly clear skies through the workweek. High temperatures for next week between 90 and 100 degrees.