We may break a significant record tomorrow, with the rapid development of the deepest low-pressure center (lowest sea level pressure) on record for the coastal waters of the Pacific Northwest.
For the period of the historical record, the lowest reliable central pressure for any Pacific low-pressure area off the West Coast occurred on October 24, 2021. I even did several blogs about the event at that time. As shown in the figure below, at its most intense that storm had a central pressure of 943 hPa.
While the European Center has the center at only 943 hPa.
The fact that multiple forecast models are coming up with the same solution provides great confidence in this forecast.
Ready to be impressed? Such low-pressure centers are consistent with the central pressures of a category 4 hurricane as shown by the official Saffir-Simpson scale (below). No need to head to Florida for big storms!
But as noteworthy as all this is, the big weather story will be in the western Washington interior, where a ferocious easterly wind will descent the western side of the Cascades, undoubtedly resulting in the loss of power to thousands.
I am charging my electronics and flashlights right now.
We have a very interesting...and threatening situation developing. To the west, a record-breaking low pressure center is developing. But to the east, just the opposite: cold air is leading to higher pressure than normal.
Below is the pressure pattern at 10 PM tomorrow night. The solid lines are isobars, lines of constant sea level pressure. The colors indicated low-level temperatures, with blue being cold and yellow indicate warm.
The combination of the low offshore and inland cold high results in a crazy intense pressure change over the Cascades.
As shown by the latest high resolution UW forecast of the winds for tomorrow evening around 7 PM, strong easterly winds gusting to 40-60 kt will hit the region from the Cascades to the Sound, and from an unusual direction (from the east).
The NOAA HRRR model does something similar (winds in mph)
These kinds of winds will take out power to thousands: not only will they be strong, this is early season, and the direction is unusual for the powerful winds. Vegetation is not used to it.
In Seattle, the southern part of the city is most vulnerable to such strong winds. Whidbey and the San Juans will be hit hard.
You have been warned. 😉
Thanks for the update Cliff. I really appreciate your insights and have silently followed the blog for years. You are my go to for interesting weather in the PNW.
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