Thursday, July 06, 2017

The Atlantic Blob aka Tropical Depression Four: July 5, Update A

Hey up friends… there’s a bit of a blob way out there in the Atlantic. It was looking scruffy but it has put on some new clothes today and is looking a little spiffy now so they have called it Tropical Depression Four.  It is currently at ~13N, 40W and is heading NW. Winds are currently at 30mph, but I think this is a gross underestimate and in my humble but not quiet opinion, it should be the next named Tropical Storm… never underestimate the Don. Tropical Storm Don that is… ;-)  

You can see from the satellite imagery that the convection (rainfall) has definitely improved:

How do we know that the convection has improved? Well, methinks that this is a delightful moment for a…. (drum roll) <Technical AND Forecasting Alert!>. A double bill… lucky times are here! ;-)

<Technical AND Forecasting Alert!> Satellite Imagery: I mainly use three sorts of satellite images: visible, water vapour (spelled with a ‘u’ of course ;-), and infrared. To access these, go to this NOAA website: http://www.ssd.noaa.gov/PS/TROP/floaters.html. Click on the storm of interest (you can look at storms anywhere in the world from here), and then I usually look at the 'Animated GIF with Lat/Long' column (on the right). But you can have a play and click on the rest of the images because it's fun! :-)

The visible one is obvious… it is what you would see if you took a black and white photo. Best used during daylight hours of course! ;-) To see the center of circulation of the storm I usually look at the visible satellite imagery - never the infrared satellite imagery unless it is a very well defined storm.

The water vapor image is also pretty obvious…it shows how much water vapor there is in the atmosphere. I think the NHC ran out of paint this year – these images were much easier to see last year (and for many years before then) when they were colour-coded. They used to show brown areas which were dry (think of parched deserts) and any other colour indicated some amount of water vapor, with green being a lot. However, now it looks like shades of gray on this site… didn’t I already have a little rant on using the colour gray?? BUT, you can still look at a colour version of this on a different NHC page: http://www.nhc.noaa.gov/satellite.php. Scroll down and find the basin of interest, and click on water vapor (the last link under each list). I like the animated GIF for the ‘movie’ version. Don’t use the Adobe Flash version.   

The infrared satellite image is the most interesting and useful though because not only does it show where the storm is, but it also gives us an indication of how strong it is and what sort of weather we have. (To get to these, click on the link marked 'AVN' (or IR AVN) on either of the two pages above) The colours represent how high the clouds reach into the atmosphere because they are based on the temperature at the top of the cloud (which is what the satellite sees). It gets colder the higher you get in the troposphere (you should know all about the troposphere by now – I mentioned it at least two weeks ago!), so we can tell from cloud top temperature how deep the clouds are and therefore how strong the convection is! The red colours are very big high clouds with the coldest temperatures (other than a dark gray), and blues and whites are lower, warmer clouds. The redder the cloud colour, the more active the convection. My general rule of thumb (having seen these images and lived under them at the same time) is that blue and yellow areas are mostly clouds, with some rain in the yellow areas. But as you get to the orange and red, you get thunderstorms and possible tornadoes (especially in the red/dark gray areas). As I said, there is no point looking at infrared imagery to find the center for weak systems. The clouds are a bit too messy. <End Technical and Forecasting Alert!>

The reason why TD Four was struggling earlier was because it was caught under the Saharan Air Layer (SAL) as it moved westwards across the Atlantic:

A layer of dry and dusty air from the Sahara Desert (ingeniously going by the name the 'Saharan Air Layer' (SAL)) tends to inhibit storms from developing.

Hmm… I do believe there is time for (drum roll) ANOTHER <Science and Forecasting Alert!>! J Squeal! J (go on, grab another glass of wine… I am!).

<Science and Forecasting Alert!>The dust that comes off northern Africa quite often travels westward across the Atlantic towards the Caribbean and Florida, amongst other places. This is called the Saharan Air Layer. It has two major impacts. The good one (especially good if you want a social life and are writing a hurricane blog during an active season) is that it tends to suppress tropical storms, in particular it impacts their ability to get their convection groove on. The bad impact is that, amazingly, it carries with it microbes and stuff (technical term for ‘stuff’ ;-)) across thousands of miles, and these have been known to result in an increase of certain health issues along the western side of the Atlantic – especially respiratory illnesses. 

In the satellite image above, the red and yellow bits are the dust levels. That red indicates areas where you’ll need an industrial strength vacuum cleaner to suck up all the dust, and the yellow areas are places where a feather duster used daily might work ;-).  You can see TD4 to the west of a large area of red. This image is from the University of Wisconsin CMISS page, which is an excellent website for this sort of handy information! Those of you in the Caribbean know about this, because a red layer of dust appears on cars when there is a strong SAL (I saw it myself a couple of weeks ago – it’s just like every day in LA!). 

You can find the SAL map from this fantastic University of Wisconsin website: http://tropic.ssec.wisc.edu/tropic.php, should you want to have a look for yourselves (and I'm sure you do! :-)). Click on the colour block in the lower map for the part of the world you are interested in (North Atlantic in this case), and in the drop-down menu (amongst a number of other things) you will see 'Saharan Air Layer Analysis'. Click on the Saharan Air Layer and you will see the map above. Easy peasy! Now you are all experts in the SAL! J <End Science and Forecasting Alert!>

I’ll keep an eye on this one, but I don’t think it will get too strong:  this storm is heading NW and although it has moved away from the bulk of the SAL, there is some more ahead of it which may inhibit it from too much development (along with a spot of wind shear).  

More tomorrow… or maybe not if he doesn’t develop any further. You know how it goes. J

Ciao (I'm practicing my Italian for the future TS Don),
J.


--> Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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. 

Wednesday, June 21, 2017

Tropical Storm Cindy: June 21, Update A

Not much time for dilly-dallying for the rest of this week... so luckily, Tropical Storm Bret went away yesterday. Clearly all that standing on the seawall and blowing and waving my arms around in my Caribbean location worked. I hope the locals thought I was doing Tai Chi or Yoga or something.... ;-)

That leaves us with the lovely Tropical Storm Cindy, who is in the Gulf. She's currently at 27.3N, 91.9W, heading NW at a stately 8 mph. Winds are 60mph, and central pressure is 997mb. She's did move a little more to the west, and is currently on track to make landfall between the Louisiana/Texas border overnight (Thursday night): 

An interesting feature the NHC have added (probably one of the two which meets my very high standards!) is that windfield to the track... so you can see the extent of the storm on the same map as the horrible track map. By the way, if you are looking for this map, on the NHC website, go to the storm of interest, and click on Warnings/Cone Static Images... or, in as they used to say in the public-friendly, normal English days... the track. You can click on tabs to remove the forecast track line, that orange blob they are calling the wind field etc. I find this one much faster and easier than the 'Interactive Map' link which takes an age to load (especially if your connection isn't great) and, although you can add a google map, if you move your mouse over the map, the entire things moves so you lose your track. 

From our intrepid on-the-ground reporter, Heather P., I heard yesterday that it was "Raining steadily since early this morning in Slidell". From the satellite imagery, it looks like that is diminishing...


Anyway, I think the track is good. The intensity... I don't have time for an in-depth analysis of the data, but a mid Tropical Storm seems is about right (TS range: 39-73mph).

Must run! Stay safe out there!!
Ciao,

Jyotika

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. 

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!

Toodles!
J.

Blogs archived at http://jyotikastorms.blogspot.com/ 
Twitter @JyovianStorm
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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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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!

J. 

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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Friday, June 02, 2017

The 'Official' Start of the 2017 Atlantic Hurricane Season: June 1

Good morning everyone! I'm awake... are you? :-) And more importantly, are you ready for a hopefully boring Atlantic Hurricane season? I don’t know about you, but something boring and not-dramatic seems quite appealing these days! Much has changed since we last met, but then again, much remains the same… another glass of wine anyone? ;-)

Welcome to the Official Start of the 2017 Atlantic Hurricane Season! It’s the official start, not the actual start because as we all know, Mother Nature thought it would be fun to try and wake us up early with Tropical Storm Arlene in April. She was a short-lived ~24 hour Tropical Storm, with winds that reached a pip-squeak past breezy – it really wasn’t worth coming out of hibernation. J

It’s been relatively quiet in the tropics since then (although I am watching a tinsy winsy low-level blob in the mid-Gulf), which means I can jump right into the interesting stuff... what have the Usual Suspects forecasted for this year? Well (including Arlene)…

Tropical Storm Risk (prediction date: 26 May): 14 (+/-4) named storms, 6 (+/-3) hurricanes, 3 (+/-2) major hurricanes. 

Colorado State University/Klotzbach-Bell (prediction date: 1 June): 14 named storms, 6 hurricanes, 2 major hurricanes.

UK Met Office (prediction date: 1 June): 14 (+2/-3) named storms, 8 (+/-2) hurricanes.

NOAA (prediction date: 25 May): 11-17 named storms, 5-9 hurricanes, 2-4 major hurricanes. 

Interestingly, they are all forecasting a slightly above-average active season (with the usual wiggle room of below average in case it doesn’t pan out of course). The long-term average number of named tropical storms is 12, and the long-term average number of hurricanes per year is 6. But even more interesting to me is that they are all amazingly in agreement on 14 named tropical storms this season, with everyone expecting around 6 hurricanes! I don’t recall seeing such alignment before. I guess we’ll find out later this year if they were all right or all wrong!

I prefer my seasonal prediction (which I forecast back on the 22nd of April) which is that there will be more than 1 named storm. #JustcallmeaGenius.

This wouldn’t be the Official Start of the Season if I didn’t go over my top 10 notes about this blog so you have a reminder of what you are getting into for the next ~6 months! These are well worth reading again, but remember, if you get bored you can always watch the grass grow. :-)

Top 10 things about this blog:

1. These updates are about fun, forecasting, and education... and tropical storms (and whatever else pops into my head that may, with some imagination and possibly after a glass or two of wine, fit those three words). It is just what I think.

2. I have a British sense of humoUr... you have been warned.

3. This is my hobby - sometimes you'll get one update a day, sometime four. If you are really lucky, you won't get any. If you wish to pay me to write, let me know and I'll send out updates as frequently as you like.

4. I hope you like Monty Python, Eddie Izzard, The IT Crowd. And other Funny Stuff.

5. If you have any questions (preferably about tropical storms), please do not hesitate to ask. I will be happy to make up the answers for you. I can also cut and paste from previous entries (I’m very talented) so if I say something or use some "scientific jargon" (ooh ahh, how thrilling), please ask me about it. 

6. I often write tongue-in-cheek, which sometimes hurts my cheek but what can you do? Gentle sarcasm, irony, and puns are all acceptable forms of communication. Unfortunately, they don't always translate in writing so please don't be offended - like Planet Earth, I'm "Mostly Harmless" (Douglas Adams). Have a piece of chocolate or a drink instead.

7. I'm sure every cloud in the Atlantic is exciting to some but, unless I'm bored, I'll usually write about those that I think have a chance of developing. 

8. Despite what you may have heard, I am not always right. But then neither is anyone else. Forecasting is complicated. Sometimes the crystal ball gets smudges and you are all out of Windex to clean it and the store is closed. So PLEASE pay attention to the National Hurricane Center, National Weather Service and your Emergency Managers - especially when a storm is looming because they have the most up-to-date information!! 

9. I have stopped adding people to the listserve, so if you are still on that I highly recommend going to the website posts (http://jyotikastorms.blogspot.com). They are much prettier. I am still working towards transitioning to the website only format anyway… as a part of my top-secret grand plan to take over the world (bwa haa haa - evil laughter in case you were wondering). 

10. I confess; I am a twit. I am on twitter (@jyovianstorm). Twitter is cool. Just like bow-ties are cool. (Dr. Who). I will post these updates on Twitter, but I’ll also tweet about storms in other basins so if you want to catch up between updates, that’s the place to lurk.

I’ll just wrap up with a couple of bits of news from today...

First, something topical... I see both NOAA and FEMA are in the news today (thanks to all who sent me those news items). Yes, this is the start of the hurricane season, and yes, the President has not yet picked a head for NOAA or FEMA, however there are acting Heads for both of these federal agencies in place so hopefully should things go pear-shaped during the hurricane season, there will be some response! I'm not too worried about those appointments. Somewhat more concerning are the budget cuts being proposed by the President for NOAA. Should all of them come through (unlikely, but one never knows), then there may be a dent in the hurricane forecasting capabilities - for example, I use the NESDIS products for this blog and they are facing an ~18% cut. Regardless of where you sit in the political spectrum, I just wanted you to be aware that the proposed cuts to NOAA's budget may be a problem.  

Second, whilst the world is discussing and debating the consequences of the US pulling out of the Paris Accord and other serious matters, feathers are flying in Canada as it struggles with its own scandal over the counterfeit Giant Yellow Rubber Ducky it is renting to celebrate its 150th birthday!
Photo credit: Getty Images (You can find oodles of stories about this on the interwebs)

A number of words spring to mind about this: unusual, fun, cute… but counterfeit!?! Surely if you were going to counterfeit something, wouldn’t you pick something a little less obvious? How many giant yellow floating rubber ducks can there possibly be in the world? How on earth did anyone think it would go unnoticed? 

That’s it for today. Oh, and if you see a spare giant yellow rubber duck lying around, please let me know... I think it’s adorable. J

Toodle pip for now!
J.

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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