Storm Dennis was one of the deepest Atlantic storms in 50 years

Storm Dennis has now moved into Europe. This blog covers historical perspective and the storm's highest wind gusts.

Feb. 28, 2020: Storm Dennis will go down in history as one of the strongest extratropical storms in the Atlantic. Despite model forecasts of as low as 913 mb central pressure, the Ocean Prediction Center's analysis indicated that it dropped to 920 mb. Here is what it looked like on the OPS maps:

The storms -- there were several that built Dennis -- caused a wind gust of 159 mph in Iceland and 118 mph in the United Kingdom. Below is a list of other U.K. gusts:

Wind gusts in the United Kingdom during Storm Dennis

With a low pressure of 920 mb, only two storms on record have surpassed it:

Ranking of the strongest extratropical storms in the Atlantic.

The data above comes from David Roth of WPC, who has created a text file listing over 90,000 points recorded for every storm in the Northern Hemisphere between 1974 and 2020. I took this file into Excel and generated the following plots:

Figure 1: World central pressure points recorded below 920 mb, from David Roths file.

Of the ones I've annotated under 920 mb pressure, most are typhoons. Two are hurricanes (Gilbert 1988 and Wilma 2005). Only two were extratropical (Not Named 1986 & Braer Storm 1993) which were 908 & 916mb (although Weather Historian Chris Burt puts them both at 912mb).

Figure 2: Zoom on central pressure points recorded below 920 mb, 2017-2020.

This second plot shows only those beyond the year 2016. As you can see, two again were hurricanes (Irma 2017 & Dorian 2019) -- the rest were typhoons, and there were no extratropical storms during that time period that fell below 920.

Another database to consider is the european ERA5 reanalysis, where the European Model has been hindcasted back to 1979. Ryan Maue says that Dennis also ranks #3 by that standard: