East Pacific Hurricane set to hit Gulf of Alaska

[Ashwin D]

There has been a strong negative velocity potential(divergent irrotational part of the total wind field) in the North Pacific in the last one week -

http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Figures/curr.vpt.7day.figb.gif

and it looks like it has spawned off a East Pacific Hurricane.

http://www.opc.ncep.noaa.gov/P_sfc_full_ocean_color.png

The Low(967 hPA) is centered around 50 N and 140 W and NWS expects it to move into the Gulf Of Alasks.

The Northern Pacific region has had a strong negative OLR anomaly for the past one week.

https://www.esrl.noaa.gov/psd/map/images/olr/olr.anom.7day.gif

 

[Ashwin D]

https://www.esrl.noaa.gov/psd/tmp/composites/compday.86bCf9S6X2.gif

You can see that the negative velocity potential at the 200 hPa has been present for over a month since end of February in the North Pacific. So an associate who works on them calls them a stationary signal and the physics behind it is the same as standing waves - https://en.wikipedia.org/wiki/Standing_wave

 

[Paul Knightley]

I see an extratropical cyclone but certainly not a hurricane - are you just referring to it being a powerful storm with that naming?

 

[Ashwin D]

You are right it is an extratropical cyclone but with hurricane like winds. When the warning was issued the speed was 64 knots same threshold as a hurricane.

Paul - if this post needs to be moved to another forum and not tropical please go ahead and do it. I did not see a category for extratropical cyclone