Sunday, June 18, 2017

The Atlantic Blob and the Caribbean Blobette: June 18, Update A

I'm on travel, so luckily for you, this week may be a little tricky on updates on a couple of blobs hanging out in the Caribbean and Atlantic - I'll jump in when I can. And where am I visiting? Why, thank you for asking... I'm in the Caribbean. It's a bit breezy here. ;-) 

Caribbean Blobette

This blobette is in the Yucatan area. There is both convection and circulation in the lower half of the troposphere (ooh... first <Science Alert!> of the season - doesn't that make you sing with joy? :-) see below for the Science Alert on 'troposphere' if you need a refresher) - although the convection is very disorganized and I agree with the NHC on that. If Mother Nature got it a little more organized, this would become a Tropical Depression with a very rapid jump to Tropical Storm because that's all it would take. But for now, the NHC have it under observation. They will be sending in a Hurricane Hunter plane tomorrow if needed. The forecast is that it will move over the Yucatan peninsula and into the Gulf, where it will become a tropical storm. Where she goes when in the Gulf is a little tricky to figure out at the moment, because we don't quite know where her current center is... I think the center is a little north and east of where the NHC think it is (it looks like they have the 'x' at 19N, 86W):

To me, it looks like it is actually going to pass a little more through the Yucatan Channel, perhaps clipping the peninsula. As a consequence, I think it may be a little stronger than the NHC think and as soon as the convection gets organized, I think she'll be a Tropical Storm. 

<Science Alert!The troposphere. Our atmosphere is divided into layers – like a delicious trifle or seven-layer dip or lasagna (depending on what country you are from). In each layer the air temperature either increases with height or decreases with height. The troposphere is one of these layers. It is the lowest section of our atmosphere and extends up from the earth (ground zero if you like) to about 15-16km in the equatorial regions, and to about 8km in the polar regions of the planet. This is the layer of the atmosphere we live in, this is the layer we breathe. All our 'weather' essentially occurs in the troposphere. The troposphere is defined by decreasing air temperature with increasing height. You would know this if you climbed a mountain. Or the easier option, of course, is to just look at pictures of mountains and see the snow at the top (known as the ‘Flat Florida Option’). ;-) The top of the troposphere is called the tropopause. Strong tropical storms have clouds that reach as high as the tropopause - and in a few very strong cases, they can extend even higher into the next layer up - into the stratosphere, which is the layer of the atmosphere above the troposphere. The stratosphere is defined by air temperature increasing with height. The ozone hole is in the stratosphere. The top of the stratosphere is around 50km height and is marked by the stratopause. And the layer above that is mesosphere, where air temperature decreases with height again... and so we go on until we get to space...<End Science Alert!>

Atlantic Blob
This blob is centered around 7.9Nm 52.4W, so it is quite far south and fairly close to Suriname and Guyana - a little unusual to be that far south and so close to South America. It is currently moving west at 23mph. The current forecast is for it to start moving WNW, heading towards the Windward Islands. I don't see any reason for this not to happen, so I'll go with this forecast track. 

The circulation is really very good in the lower half of the troposphere and the convection is also improving as you can see in this satellite imagery video:

I would actually already call this a Tropical Storm, if not a Tropical Depression at this point! However, the NHC have a new term... 'Potential Tropical Storm'. <Minor Rant Alert!> Please note, as far as I can tell, this is a made-up term for advisory policy purposes, not an actual scientific/storm-type designation.  So, apart from being confusing and perhaps unnecessary for most of us, this gives them permission to have... (quote from the NHC site):

"... the option to issue advisories on disturbances that are not yet tropical cyclones, but which pose the threat of bringing tropical storm or hurricane conditions to land areas within 48 hours. Under previous policy this was not possible. These systems are known as Potential Tropical Cyclones in advisory products and are numbered from the same list as depressions."

I'm not against issuing advisories, but they keep introducing extra layers so their policies will allow them to issue these - seems a little backwards and overly complicated to me. Surely there must be a simpler way? <End Minor Rant!>

They will send a plane in to investigate on Monday afternoon and the current forecast is for it to fizzle out after it crosses into the Caribbean. 

The next name is Bret, followed by Cindy (in case she makes an appearance this week too).

Adios for now!


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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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