Tuesday, June 20, 2017

Tropical Storm Bret and the Gulf of Mexico Blobette: June 19, Update A

Straight to Busy-ness...

Tropical Storm Bret
Not a huge surprise that the blob formerly known as the Atlantic Blob is now Tropical Storm Bret. Since yesterday he has moved in a WNW direction and is now at 10N, 61.3W and is now on top of the very southern end of the Windward Islands - Trinidad and Tobago. He is still moving WNW at a very rapid 23mph and again, I see no reason to not go with the NHC forecast which continues him on this path. 

The official pressure is 1008mb, winds are 40mph (Tropical Storm Range: 39-73mph). I think this may be a little low given the circulation, which is strong and well developed in the lower half of the troposphere and the convection, which spreads over a large portion of the western Caribbean, even though the center is to the south:

This spread in convection is due to wind shear. So although the vorticity is pretty good, between the wind shear and his interactions with land (Venezuela and Trinidad) I think he is still just a weak-to-mid-sized Tropical Storm. 

A couple of things that I find interesting about this storm are: (a) the speed - 23mph is really fast for a tropical storm which is not being aided by a low pressure front; and (b) he is quite far south for a storm this far to the west - I don't often mention Trinidad (twice in the last 11 years), and have never mentioned Venuzuela or Suriname in this blog (until yesterday). This means that the high pressure that helps to steer Atlantic storms is quite far south... probably because it is June and still fairly early in the season. This storm formed mid-way across the Atlantic - normally at this time of year the storms form in the western Atlantic, Caribbean, or Gulf. In the last ~170 years, I think this may be the second time a storm has taken this track at this time of year - and I think the last one was many many moons ago!  

But moving on to the other big story...

Gulf of Mexico Blobette
For anyone on a cruise ship in the Gulf, heading to the Yucatan (yes, that would be you Mr. J!) I would just...  
(Monty Python in case you didn't know! ;-)). 

I assume your Captain has moved to a temporarily safer spot! 

So, also not surprisingly, this storm was upgraded to a 'Potential Tropical Storm'. I think they are more than a bit off in this assessment - this one is definitely a Tropical Storm by now in my estimation. Officially, central pressure is 1000mb, winds are 40mph. She is at 24.4N, 89.5W, moving NNW at 8mph. 

First, <Mid-sized Rant Alert!> I am still confused by this 'Potential Tropical Storm' nonsense... the NHC wrote in their second advisory that this storm "had consolidated into a single low-level circulation center with a pressure of about 1000 mb."

By definition a Tropical Depression is a closed circulation, with winds of more than 17mph!! This system has closed circulation, and winds are officially 40mph. A closed circulation and winds of between 39 - 73mph by DEFINITION is a TROPICAL STORM. 

Whoever has made the changes to the advisories and website graphics this year has really done a poor job. I would love to see someone at the NHC explain how by definition this is not a Tropical Storm! <End Mid-Sized Rant Alert!>

Second, it looks like the center was incorrect yesterday and she didn't cross the Yucatan but stayed more over warmer water of the Yucatan Channel and therefore moved smoothly into the Gulf. I agree with their center of circulation today. 

Her circulation is getting stronger in the lower half of the troposphere, and you can see in the image above that the convection from this storm extends from central America up the eastern US seaboard. It is elongated, again due to wind shear. There is more wind shear ahead of her, so that will help to keep her a little more in check, but I think she is a storm with winds of around 50mph at the very least - which is stronger than the NHC think. 

She is forecast to head towards the northern Gulf - Texas/Louisiana: 

By the way, I don't like this new version of the hurricane forecast chart either - it is difficult to find on the NHC website, looks like all the other graphics, and is pretty boring... since when was land 'gray'? Grrr.... Me:

(credit: grumpy cat)

I will have to have ice cream to recover.

I will look into it, but it I think the data I was using to figure out the track stopped being produced in March of this year. From the limited data I do have, I think this storm may move more to the west (or perhaps slow down further) because there is high pressure building up in front of it. Although I may not be able to give you an idea of the track if I can't find another source for that data, as I have said before, the NHC forecast is generally good 24 hours out from landfall... we'll see what it is like at longer lead times this year.

That's it for today methinks. Stay safe if you are out there!


Blogs archived at http://jyotikastorms.blogspot.com/ 
Twitter @JyovianStorm
DISCLAIMER: 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 the National 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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