Ironically, this period of warm temperatures and sun was preceded by cool temperatures and snow down to around 1000 ft on Monday, with nearly a foot of snow at Snoqualmie and loads of accidents in that pass. The culprit: cold air behind a strong cold front and a Puget Sound convergence zone that extended into the mountains. But that is all behind us now!
Snoqualmie Pass at 6:17 PM on Monday evening hardly looked like a place preparing for a heat wave!
During the next week a major ridge of high pressure will build and hold in place over the eastern Pacific. Let me show you, using the upper level forecasts at 500hPa, about 18,000 ft above the surface.
The forecast for Thursday at 11 AM, shows a ridge, but a weak short-wave disturbance will bring a few clouds and hold back the temps. Decent weather in the 60s.
By Friday at 5 PM, the disturbance is well through and the ridge is building. Sunny and low 70s.
The ridge builds over the weekend over us and a low develops over California--not good for the sun-accustomed folks of southern CA, but a very warm pattern for us due to the easterly flow above the northwest. 80F is NOT out of the question for many of you.
OK, some of you are ready to chide me. You can't trust one model run! What do the ensembles (many forecasts made with slightly different starting points or physics) show? Well, you are right, and below is the output from the North American Ensemble Forecasting System (NAEFS) for Seattle. The top panel show temperatures (C not F!). The line in the middle of the yellow boxes give the median values (half of the simulations are above, half below). The highest and lowest forecasts are shown with the "wiskers" protruding off the boxes. Bottom line: warming, with very little doubt about it during the next five days.
The second panel gives precipitation. VERY dry in nearly all the ensemble members for the next week or so.
Want to help find out the effects of coal trains on the local environment?
Atmospheric Chemistry Professor Dan Jaffe is ready to begin a study on air pollution from trains, especially freight and coal trains, in the Puget Sound region. Several state and local agencies told him that this work needs to be done, but that it is too politically hot for them to fund.
Considering the importance of this work, Dr. Jaffe is going to depend on crowd funding to support this effort. For more information and perhaps to help, please check out this website: