We are now entering the driest time of the year in the Northwest. The time when we are usually drier than the Southwest desert.
Below is a graph of the probability of getting a trace (0.01 inch) or more in buy compared to the day in Seattle. The last two weeks of July have an extremely low probability of rain.
However, this year we could see some rain.
Tomorrow, an upper trough will move over British Columbia, bringing rain to the coasts of Western Australia and Northwest Washington (see upper floor map (500-hPa pressure, about 18,000 ft) at 4 a.m. Thursday two below)
Total precipitation forecast through 7 p.m. Monday from the NOAA/NWS HRRR model is shown below. Wet coast and northern Cascades
British Columbia will be watered more thoroughly, with the UW modeling system showing up to an inch over the coastal mountains and Rockies through Tuesday. This is good because it reduces the threat of wildfires in the province.
Temperatures will cool down on both sides of the Cascades on Monday. It’s a little cooler in the west today, Sunday as some shallow sea air tries to push inland. But much cooler on Monday morning
As in any cooldown in our region, there is a risk of temporary wind intensification on the eastern slopes of the Cascades and immediately downwind.
Such wind intensification would occur during the event, which would result in increased fire risk in the short term east of Washington, as suggested by the Hot-Dry Wind diagnosis for 8 p.m. now (below, orange and red indicate more problematic conditions). However, it is very good for generating wind power.
So people in eastern Washington need to make sure they don’t start any grass fires.
After the upper trench passes, temperatures in the west will warm below 80 degrees Celsius, while eastern Washington will return to 100 degrees Fahrenheit.
The good news about bushfires next week is that there will be less thunder and weak winds. So the threat of wildfires is mainly from small grass fires, often caused by humans.
