14 October 2016
The last time that the NWS office in Portland,Oregon issued a tornado warning was in November of 2014, but they issued one today as an intense low moved through the Straits of Juan de Fuca and brought gusts over hurricane force on the aptly named Hurricane Ridge at Olympic Nat. Park. Winds are gusting to 44 mph south in Astoria,Oregon and this is just the first storm. The storm tomorrow will be worse, with model guidance showing a pressure of 971 hectopascals, which is a typical pressure in a hurricane.
This next storm will bring much higher winds to the Oregon coast than what they are seeing tonight, and then it will track northward to Puget Sound impacting Seattle and Victoria/Vancouver in Canada. The low pressure system (that will intensify into a severe wind storm) is well west of the area in the Pacific tonight, but water vapor images from the GOES West satellite show strong hints that it will rapidly develop. The dark area on the image below shows dry air in the mid levels, which is being caused by sinking air behind a potent upper level low (Sinking air warms and dries out, producing the darkening on the water vapor images).
This is the pressure wave that will become a deep low pressure system with hurricane force winds around it. It’s a good example too of the usefulness of seeing the atmosphere in different wavelengths of non visible light. GOES-R will have even more channels in the IR bands (and much higher resolution) when it launches in a few weeks.
(I’ll be at the Cape for the launch and will blog more about it!)