We’ve seen a dramatic shift in most model solutions over the past 48 hours. On Monday, models showed a very deep low – approximately 965-970 mb – making landfall near the northern tip of Vancouver Island, bringing very strong winds/extremely high waves to the coast, windy conditions to Western Washington, and breezy conditions to Western Oregon. Since then, models have trended weaker, smaller, and further south with the storm. Yesterday, models showed a 970/980 mb low making landfall along the North/Central Washington Coast, bringing gusty winds to Portland and very strong winds to Western Washington south of Seattle. This morning, models moved the low south towards the central WA coast and weakened it further, but these changes actually increased the high wind threat for Portland due to the storm being much closer.
However, tonight’s model runs are much, much weaker than previous runs, and an increasing number of models (including the 00Z 11/12 WRF-GFS, which is shown below) lack a discernable cyclone completely. Due to these changes, I’ve decreased my wind speed forecasts for Friday.
I’m forecasting winds gusting 20-30 mph for Portland and 35-45 for the coast, highest Friday afternoon. There is still a lot of uncertainty in wind speeds (for example, wind speeds would be even less if we saw the solution given by tonight’s WRF-GFS, but I don’t want to be that aggressive yet), but I’m confident that we won’t see any sort of impactful windstorm out of this.
The below images show how the low has evolved in model runs from Monday morning through tonight. The top image is from Monday’s 12Z run, the second is Tuesday’s 12Z run, the third is Wednesday’s 12Z run, and the 4th is the current run (Thursday 11/12 00Z). Note how the low became smaller and smaller with subsequent runs… and it is completely absent in the most recent run.
Credit: University of Washington
Credit: University of Washington
Credit: University of Washington
Credit: University of Washington
Regardless of wind speed, this storm will deliver plenty of rain to the lowlands and snow to the mountains. Winter Storm Watches are in effect for as much as 15-30 inches of snow above 5,000 feet, and lowland rain totals from now through 4am Saturday are expected to be 1-1.5 inches across Western Washington and Oregon with the exception of much lower totals in a rainshadow NE of the Olympics. Approximately 0.25-0.5 inches of rain will occur with a front on Thursday afternoon, and the rest will occur throughout the day Friday.
Credit: Pivotal Weather
1 Comment
Me, I just come for all the pretty patterns! 😂 just kidding… well partly.. weather fascinates me.. I have taken a lot of weather photos over the years! Love what you do… thanks!