Saturday, August 15, 2020

Tropical Storm Josephine and Tropical Storm Kyle: August 14, Update A

'Tis the season I suppose. We have not one but two little Tropical Storms out there today. Guess I'll just jump in...

Tropical Storm Josephine 

She's currently at 18.3N, 57.4W, heading WNW at 16mph. There's not been any substantial change in the track forecast - still heading for the broader Bermuda region next week.

She's still a weak Tropical Storm with winds of 45 mph, central pressure 1005mb. She still has some pretty decent convection and the clouds are showing a nice 'outflow' along the western and northern side (that circular jagged sort of pattern we see with well developed storms): 

I would say she's got winds stronger than 45mph - around 50-55mph or so. She's almost through the Saharan Air Layer - I expect she'll have pretty much cleared it tomorrow: 

But she's not quite as strong as she was trying to get yesterday because there isn't any vorticity (circulation) signal in the upper troposphere now, so I think that wind shear has been enough to keep her in check. There is, however, a strong vorticity signal in the lower and middle troposphere as you can see in the vorticity maps below (see the Science Alert! & Technical Alert! in this post for a refresher on vorticity/circulation and vorticity maps). The first map is the lower troposphere at 850mb:

The second is the mid-troposphere at 500mb: 

See how the two red blobs (technical term ;-)) are offset from each other? And how neither of them are over the Tropical Storm symbol that magically appears where the official center is? That's all signs of strong westerly wind shear (meaning it is blowing from the west to the east).

Now, for those of you who are awake, you may have spotted the second Tropical Storm in the vorticity maps... 

Tropical Storm Kyle

He was just a disturbance in The Force yesterday but, like me, ate too much ice cream and has now blossomed into a fully fledged Tropical Storm with a name today (which I do not agree with by the way). He is at 38.3, 70.0W, heading ENE at 16mph.

He's a weak thing with winds also at 45mph, central pressure 1006mb. I'm not sure I agree with them naming this one yet - his winds are thought to be that high from limited observations and some assumptions made by the NHC that tip the balance in favor of winds that are high enough. They also have an observation from one ship that recorded winds of around that speed at one location, so clearly we can extrapolate from that. He is under a lot of wind shear (more than Josephine), which we can see in the satellite imagery as the clouds stream off to the northeast:

Interestingly, you'll see from the vorticity maps that his vorticity signal in the lower level of the troposphere (at 850mb) is a little elongated and attached to a line of higher vorticity, which is what we see in a front - this means he's actually not a fully fledged Tropical Storm, but rather a system that is getting some of it's energy from that front. In this case, I would also expect higher wind speeds, and we see that sort of closed circulation in winter storms that are related to fronts. So again, I don't agree with naming him. 

Here's a cool infrared satellite image of the entire North Atlantic - see the huge difference between an actual Tropical Storm (Josephine), and one that seems dodgy to name (Kyle). 

Even though they think he will get stronger as he moves north and gets over cooler water (because he's really a front, not a Tropical Storm), at least his forecast track will keep him away from land.

<Minor Rant Alert!> Oooh... it's been a long long time since I've posted a Minor Rant Alert! (I must have mellowed with age ;-)). So, are you ready...

I know there's some flaff about TS Kyle being the 11th named storm, early in the season blah blah blah. But really, that's more of a red herring to ramp up the anxiety, so don't worry about that. There are too many other things going on this year to worry about storms that we can name if we squint and turn the map sideways and that aren't going to go near anyone (unless you happen to be on that one ship who reported the winds). Next thing you know, someone will get a sharpie out and start drawing fictional storms on the map. 

If I were you, I would focus on the more important news items - like the dismantling of the US Postal Service, which in my often-not-very-humble opinion is a completely daft idea! But bravo in alienating yet another group of voters just before the election! What's that game where the winner is the one to get to zero first? Anyway, in the movies, there's always a hero... so who will it be? Perhaps UPS or FedEx could step in and offer to cover mail-in voting ballots at no cost? Or a bank could offer to devise a secure electronic voting service at no cost (if they can keep everyone's money safe, surely they can handle voting)? Or Amazon (or Mr. Bezos) could to step in and save the USPS or offer free services for mail-in voting? Or how about every politician who has a US Post Office in their district put their foot down and sort this mess out... because those 140 billion pieces of mail that go through the USPS (prescriptions, checks, cards to make you happy and give support etc) aren't going to get to those 160 million addresses in their districts by themselves. &ltEnd Minor Rant Alert!>

And on that note, I better call it a night (because it is :-)). I'll be back tomorrow, by which time I expect the USPS to have been resurrected and machines returned... (did I mention I was an optimist? :-)). 

Ciao for now,


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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