Extreme Storm Inbound

High wind and coastal flood warnings are in effect for much of Alaska's west coast tonight, accompanied by strongly worded statements from the NWS about extreme impacts caused by the re-invigorated remnants of Typhoon Halong.  The storm will hit the Yukon Delta region extremely hard, perhaps locally worse than ex-Typhoon Merbok in 2022.

Here are the latest weather model forecasts for 3am tomorrow morning.  While the expected central pressure is not quite as low as earlier indications, the wind forecast is quite extreme for a narrow zone to the south of the storm center.

The NWS graphic shows the timing of high winds for a few communities in the area. 

I calculated the horizontal pressure gradient in the hourly forecast from the GFS model, and the following image shows the zone of maximum gradient, which is approximately equivalent to the area that will see the maximum wind speeds.

The same calculation applied to ERA5 reanalysis data from ex-Merbok suggests that the peak pressure gradients were considerably less in 2022 - see below.  I think this is because Merbok was a much larger storm in terms of spatial extent; the peak winds may have been lower, but the circulation's total energy and the storm surge were enormous.

Another point of comparison is the so-called Bering Sea Superstorm of November 2011:

See the following link for the first of several brief posts on this blog about the 2011 storm:

https://ak-wx.blogspot.com/2011/11/potentially-calamitous-storm-for.html

This storm is also included in the UAF/ACCAP extreme events library.  Read about some of the impacts here:

https://uaf-accap.org/document/extreme-event-2011-bering-sea-storm

Of course Merbok also has a write-up:

https://uaf-accap.org/document/extreme-event-2022-merbok