Sunday, May 17, 2020

Tropical Storm Arthur: May 17, Update A

Dear Fellow Inhabitants of Planet Earth, I know we were all looking forward to the fun swinging '20s, but I have to say this start is a little too swingy for me! 

I guess getting up a little ahead of the official start to the season is par for course this year. Luckily we ordered 480 bags of PG Tips tea, so I'm set for this week at least. Onwards we go with the unofficial first post of the 2020 Atlantic Hurricane Season... 

Tropical Storm King Arthur was crowned yesterday and is a weak thing at the moment. Winds are 45mph, central pressure 1002mb, is which makes him a weak tropical storm really (TS range: 39-73mph wind speed). He is currently at 31.5N, 77.2W heading NNE at 9mph. His forecast path takes him close to the North Carolina outer banks tomorrow and then out to sea:

The satellite imagery is showing some convection (technical jargon for that rainy stuff ;-)), but it isn't very evenly distributed:

To give you some idea of what this shows - the orange areas have the strongest convection - heavy rainfall, maybe some thunder, the yellow is heavy rainfall, green is moderate rainfall, blue is a light drizzle, and the grays are just lovely clouds. It looks like some parts of the North Carolina coast are already getting a bit wet.

Although he looks a little ragged at the moment, I expect him to get stronger (as does the NHC) and his convective activity to increase as he moves north. He is close to the Gulf Stream, which means he is passing over deeper warm waters. Can you believe it's already time for the first <Science Alert!> of the season?! Squeal!! 

<Science Alert!> The Gulf Stream is a very strong ocean current that flows along the eastern US seaboard, and then heads west into the Atlantic just off the North Carolina outer banks. It is actually part of a longer ocean current system that flows from the Caribbean into the Gulf of Mexico through the Yucatan Strait, where it is called the Loop Current. This then flows out of the Gulf of Mexico through the Straits of Florida and along the eastern side of Florida, where it is called the Florida Current (surprise!). Once the Florida Current gets to Georgia, it is the Gulf Stream. This entire system flows very quickly and carries deep warm Caribbean waters north and into the Atlantic. Tropical storms churn up the water underneath. So the importance of moving over deeper warm water is that a tropical storm will churn up more warm water instead of cooler water and has a jolly good chance of becoming stronger. <End Science Alert!> 

The other reason TS King Arthur will get stronger is because the wind shear is weak at the moment. The NHC forecast that his winds will get to around 60mph tomorrow, making him a mid-size TS. I think there's a possibility he could get a little stronger than that in a couple of days because of the influence of the ocean. 

I see that I didn't finish off the last season in my usual suave manner (I must have been busy with that work malarky again) ... so before I sign off for today, it turns out that last year was an average year (as far as the Atlantic Hurricane Season went). The final tally was 12 Tropical Storms (of which two were Subtropical), and 6 hurricanes of which 3 were major (cat 3 or higher) - Hurricane Dorian of course (cat 5), Hurricane Humberto (cat 3), and Hurricane Lorenzo (cat 5). 

Until tomorrow my friends! 

Toodle pip,

Twitter: jyovianstorm
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 

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