Hurricane Cristobel: August 28, Update A

I've arrived on this other planet called 'DragonCon', along with the Klingons, Wolverines, Daleks, Harry Potters and Hermiones, a gaggle of Superheroes, and a collective of other beings. So entertaining. Of course I'm Storm... who else would I be? ;-)

I see Cristobel is still officially a Hurricane with winds of 80mph, central pressure 973mb. I'd agree with this wind speed as he was trying to develop a little eye a few hours ago (not very clear though), so that would be around 90mph:

However his convection is relatively weak for such a storm, with very few strong thunderstorms and it looks like it is falling apart a bit. This is because his top is really part of that front that we've seen all week:

He's trying to be helpful and avoid most landmasses except one... (bwaa haa haa) 

Bardarbunga watch out! I see the B-movie title already... Hurricano! ;-) (copyright: Me!)

He is currently at 38.5N, 61.5W heading ENE at 36mph.  That superfast forward speed is another sure sign that he is caught up in a front, which is carrying him to the northeast.

I may not be on here tomorrow unless the other little 'disturbances' do something silly, but I don't think much is going on with Cristobel.

If you are at DragonCon, just a reminder that I'll be giving a talk on the wonderful stuff that goes on at XPRIZE at 5.30pm tomorrow, and right after that I'll be on a disasterlicious panel at 7pm on "A Practical Guide to the End of the World!" (panel will also contain a geohazards expert - earthquakes, volcanoes and the likes; a nuclear astrophysicist - solar flares, meteors etc; a biologist - sharks, dinosaurs etc; and an infectious diseases physician - plagues, ebola etc.- I think between us we have it pretty much covered! :-)).

Toodle pip until Saturday!
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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Hurricane Cristobal: August 26, Update A

Oh how the days do fly by when you are having fun! I have to pack to go to another planet (disguised as a city called Atlanta) tomorrow, where there will be weird and wonderful alien beings. :-) Who else is going? Let me know! I'm giving a talk on Friday at 5.30pm on XPRIZE. Then at 7pm I'll be on a panel: A Practical Guide to the End of the World. Should be a barrel of laughs. Stop by and say hello! :-) :-)

Meanwhile, today, back here on planet Earth, Hurricane Cristobal is still a fairly weak cat 1 and officially has 80mph winds (cat 1 range: 74-95mph) and a central pressure of 983mb. Although official he is at 30.4N, 71.5W, heading N at 15mph, from the satellite images it looks like he is closer to 30N, 72W - a bit south and west of the official location.

Earlier today the NHC wrote: "Cristobal's cloud pattern is not typical of a hurricane on IR images. The convection is quite linear and the system appears to be embedded within the tail of a frontal zone.". Yes, thank you very much.

Since then, Cristobal tried to regain his manly identity as a Hurricane (or really a Tropical Storm) in the lower levels of the troposphere, even though he is still somewhat stuck in that front in the middle and upper levels (vorticity at 500mb - the middle of the troposphere shows that he is not an isolated 'blob'):

They did increase his wind speed slightly to 80mph, but it looks like he is having a few issues now...

Even though he still has some circulation (more than he had as a 'hurricane' yesterday) and you can see that familiar banding structure, that strong convection (red bit - lots of thundery weather) in his center just went puff in the space of about 7 hours!

There are a handful of reasons why his convection would fall apart so beautifully:
1. Sea surface temperature. Unlikely to be the cause because although he is over slightly cooler waters, with temperatures in the 27-29 deg range, it is still warm enough to keep him going.
2. Dry air. There is some dry air to his west, which does begin to get pulled into the system as it weakens, but this doesn't appear to be the initial cause:

3. Very shallow layer of warm water underneath: I think a bigger factor in his decline is that he has just moved from an area where the upper 75m of the water column was warmer than 26 deg C, to an area where only the upper 25m is warmer than 26 deg C. So as he churns away, he is mixing up water that is colder than 26 deg C, and about 26.5 deg C is the water temperature you need to really sustain a tropical storm.

I am not sure he will remain like this though. Given that he is stuck in that front, I think the convection will return (at least to some extent) as he moves north and goes over the Gulf Stream, a warm strong ocean current that runs along the eastern coast of the US and then heads east, out into the Atlantic around 35N. The upper ~50-75m of the water column in the Gulf Stream is warmer than 26 deg C.

As you can see, Bermuda, that little blip in the Atlantic, is under some cloud cover - probably a perfect day for a BBQ and refreshing beverage. ;-) (What do you mean you can't see it?!?). It does look like his center (should he survive) will pass to the west of Bermuda, but the cloudy goodness is on his east, so, well, you can obviously expect beautiful sunsets for a few days (behind the cloud cover).

Right, must dash and pack! I'll try and hop on tomorrow, but I may be sucked into a space/time vortex. I'll be back as soon as I emerge - sometime in the future.

In honour of ...
 
Nanoo nanoo, and a good day to you!
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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Hurricane Cristobal: August 25, Update A

An eminent geologist gave me the low-down on what happened in Iceland with Bardarbunga ... "Actually the Icelanders turned the volcano off using big underground magma valves. They decided that they can create more havoc and thus hold the airline industry for a larger  ransom at a later time. Hey, you gotta do what you gotta do to enhance your GDP." (Source shall remain anonymous to protect his Great Geologicalness). 

Regarding the other natural havoc in the Atlantic arena... not much time for dilly dallying tonight, alas, as I have a bit of ranting to get done.

So Cristobal is a Hurricane, hey? Officially his wind speed is 75mph, which makes him barely a cat 1 (cat 1 range: 74-95mph), central pressure is 989mb. He is located at 25.1N, 71.9W, heading NNE at 2mph. He has barely moved from the poor Turks and Caicos, who are well and truly drenched at this point I imagine!

I'm not sure I quite agree with this analysis of him being a hurricane. <Rant Alert!> Ok, truth be told, I really don't agree with this. You can't go around naming storms hurricane willy-nilly just because you measured some high wind speeds! In that case a winter gale or a tornado should be named a hurricane because it has high wind speeds. It's just not on. Cristobal is more of a front meeting a Tropical Storm rather than a full out Hurricane. Sigh. <End Rant Alert!>

Let's look at the evidence...

1. There is a lot of convection, I give them that. You can see this in the infrared satellite video:

But you would expect a lot of convection with any stormy weather over water temperatures in the 29-30 deg C. It looks more like a blob than a well-organized tropical system.

Even the NHC admit: "this system's cloud pattern does not resemble that of a hurricane, with little or no evidence of banding on satellite images." No banding. No eye. Nothing.

Of course, you could say that the long line of very active thunderstorms and rain showers streaming off to the northwest (over Bermuda) is because of wind shear. It does look like wind shear. But is it just wind shear or is something else afoot (aloft)?

2. We can look at the structure of the atmosphere to find out, and we do that by looking at the vorticity fields....

These show a long line of higher vorticity (greater circulation) stretching across the Atlantic in a SW-NE direction at all levels of the troposphere. This is the signal of a front.

Lower level of troposphere (850mb):

Middle troposphere (500mb):

Upper troposphere (200mb):

By comparison, Hurricane Marie off to the left, has the well-organized circular structure of a Hurricane. Looks very different, doesn't she?

So, the circulation is not showing the structure of a Hurricane, and the convection is not showing a Hurricane. And therefore... why would one call this a Hurricane?!? It should still be a Tropical Storm as there is a signal of one still in the lower half of the troposphere, even it if is getting a bit entangled. If I was cynical, I might even say that this is one of those 'we need the numbers' things. But luckily for you, I'm young and carefree and not cynical or skeptical or any of those other words ending in 'ical' at all, so I won't say that. Not At All.

All this silliness aside, what does it mean for you Bermudians? It looks like you're going to get a spot of rain (it looks like you may already have had some?). Although the track has Cristobal passing to your west on Weds, I would still dust off the galoshes and stock up on the tea, wine and ice cream (good advice for most situations I think ;-)). The NHC have generally been rather good on the track at 1 day (even if their intensity estimates are poor), but Cristobal is caught up with that front and is a bit bulky, so although the center may not pass over you, you might still get a bit of a breeze. I would be ready also in case the track does shift a bit more to the east - I'm not ruling that out yet.

More tomorrow. Must run... mudpie ice cream is melting... ;-)

Toodles 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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Tropical Storm Cristobal: August 24, Update A

Mother Nature pulled a fast one in Iceland yesterday! Today the scientists over yonder said that there was no sign of a sub-glacial eruption at Bardarbunga after all and something else is afoot (my leading theory is that the rumblings are caused by an alien spaceship. Obviously. ;-)). Hmm... maybe this volcano-eruption malarkey is just a ploy to make us all learn another Icealandic word?

On the other hand, a magnitude 6.0 earthquake hit the Napa region of California!! Aaagh! The WINE!!(Warning: following image may be disturbing):

(image credit: D. Duncan, via C. Kellogg)

Quelle horror!

Breathe. Breathe. Ok, I'm back...

So... at least the storms are behaving in a somewhat predictable manner. The blob in the Atlantic turned into a weak Tropical Storm Cristobal today. (Historical Note, thanks to Mr. Locke: Cristobal Colon (minus accent aigu) was the real name (in Spanish) of Christopher Columbus. His REAL real name is Cristoforo Colombo since he was Italian; however he discovered the Americas on Spanish ships so Cristobal Colon is it.)

Cristobal's winds are officially at 50mph (TS range: 39-74 mph), central pressure is 996mb. Here are the vorticity maps so we can see his circulation (and hence, structure) in the troposphere. There's something really cool in these maps... not only is there a poorly defined Tropical Storm in the Atlantic, but you get the rare privilege of seeing the structure of a cat 5 hurricane in the Pacific!

Near the surface (850mb):

 

In the middle troposphere (500mb):

 

 

In the upper troposphere (200mb):

He is barely a Tropical Storm because the vorticity is not an isolated blob, but is connected to low pressure to the north and south (like a front) - this is an indication that he is not very well-organized. Another indication that he is only a Tropical Storm at the most is that there is no blob in the upper troposphere (you only see that in hurricanes). In comparison, in the Pacific just southwest of Mexico you can see the vorticiy signal for Hurricane Marie (lower left quadrant) - she is a cat 5 storm with winds of 160mph! The circulation is so strong (the force is strong with this one ;-)), that it is white in the lower and mid troposphere, and almost white in the upper troposphere. That, my friends, is the vorticity (circulation) signal of a pretty darn-tootin strong storm!

Because he is so poorly defined, the NHC estimate Cristobal's center to be at 24.5N, 72.9W and he is stationary at the moment. He was drifting slowly to the north earlier today. It looks like the pressure fields have changed since yesterday and are opening up a path for him to move northward and stay out in the Atlantic, away from the US. He is stationary at the moment because he is bumping up against high pressure (it's like climbing uphill for him), but it looks like he should move northwards tomorrow and then to the northeast.

He does have a fair bit of rain in him... I think the Turks and Caicos are getting a bit of a washing!
This is because the sea surface water temperature is a very warm 29-30 deg C, with the upper 50-100m warmer than 26 deg C. That's enough to keep him happily fed for now.

And for those who asked... I thought the new Dr. Who was ok. Not a strong an opening episode as a couple of other Doctors as it was a bit heavy handed on the differences between this Doctor and the previous one and it was a bit chaotic. I'm not sure I like all the opening sequence changes yet either. I am also curious to see how going back to a more avuncular Doctor plays out with the new audiences. I, for one, enjoyed the old Dr. Who, and don't mind at all. :-)

More tomorrow!
Ciao,
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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Tropical Depression 4 and Volcano Special: August 23, Update A

A big day today! The much anticipated new season of Dr. Who begins with a new Doctor! :-) How exciting! Oh yeah, and that rather big volcano in Iceland erupted today.

I suppose it's time to dust off the ash from my last Volcano Special a few years ago but first there's a little Blob that's been crossing the Atlantic, now in the vicinity of the Turks and Caicos. He's a dinky little thing with winds officially at 35mph (central pressure 1005mb).

I agree with the NHC that he is just a Tropical Depression at the moment. The vorticity fields for the Atlantic show that he has some circulation in the lower half of the troposphere, but it is not very well defined yet. (I know, it's been weeks since we talked about vorticity! If you need a refresher on how to read these, check out the Science Alert in this very intelligently written blog: http://jyotikastorms.blogspot.com/2014/08/hurricane-bertha-august-4-update-a.html ;-)). Also, in looking at the satellite images, he doesn't have much structure or much convection. Pretty wishy washy... for now.

He is currently centered at 22.0N, 72.4W, heading NW at 11mph. The forecast track and intensity calls for him to become a Tropical Storm as he goes over the Bahamas tomorrow and on Monday, and then a Hurricane on Tuesday as he curves to the N and NE and remains in the Atlantic. Although the forecast track keeps him away from Florida and the US coast, I am not so sure of this yet. I think there is a possibility that his track will shift to the west. Once he reaches 39mph wind speed, we will meet TS Cristobal (which, in case you were confused, is actually a male name... the internet tells me it is 8 times more common to be a boys name than a girls). More tomorrow on this Blob!

Volcano Special
And now for something completely different! Iceland has decided it wanted some attention so it has gone and set off another volcano. ;-) Alas, this one is much larger than Eyjafjallajokull that brought air traffic to a halt in Europe for some time in 2010. But don't worry, there is a bright silver lining to this volcanic eruption... it is much easier to pronounce. Bardarbunga (minus some accents and whatnots over a few letters here and there) is pronounced BAUR-DAR-BUNG-KA, as demonstrated in this little video by some nice Icelandic chap: https://www.youtube.com/watch?v=413V0bmjvBg.

Now, just in case you are silly enough to be contemplating air travel that involves Europe or the Atlantic anytime soon, I thought you'd like to know where to look for potential forecasts and find out Bardarbunga's latest shenanigans. (Bardarbunga really does sound like a muppet name, doesn't it? :-)).

To read about what the volcano is doing, I go directly to the Icelandic Met Office: http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947. This is a pretty good site and scientists who have been monitoring the volcano will update it with a report a couple of times a day.

<Forecasting Alert!> For volcanic ash forecasting the world is divided into regions with a Volcanic Ash Advisory Centre (or Center ;-); VAAC) per region:

Each VAAC is responsible for providing the official global forecast for ash from any misbehaving volcano in it's region (see website below) so that all aircraft are using the same information and there is no confusion (a good thing to avoid, especially if you are in a plane!). The London VAAC covers Iceland and is based in the UK Met Office: http://www.metoffice.gov.uk/aviation/vaac/vaacuk.html. Should there be a need for advisories, this is the place to look. I'll write another update to let you know what's what if we need to use that page. <End Forecasting Alert!>

Now it's time for Dr. Who!! Woohoo! I have my cuppa tea and Double Decker ready for the viewing. :-)

More tomorrow!
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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Tropical Storm Bertha: August 5, Update A

Ahh... ice cream. The current favourite is Mud Pie. So delicious I might have to have another bowl to er... help me write.... :-)

Tropical Storm Bertha is now pretty weak with winds of 50mph (TS range: 39 - 74mph), central pressure 1007mb. She is officially centered at 37.5N, 68.1W heading NE at 23mph, but it is difficult to identify an actual center.

She's not really a Tropical Storm anymore even if she is bringing a bit of wet and windy weather with her...

Apart from not being able to see much of a circulation in the satellite imagery, we can also check the vorticity maps (I'm sure you memorized every brilliant word I wrote on this yesterday! ;-)) to get an idea of her structural integrity. Near the surface (850mb) she no longer has a self-contained red 'splodge' (don't be fooled, this is still a highly technical term ;-)) but is attached to another red splodge (splodges unite!) (ok, I admit it, I just like saying the word 'splodge' ;-))...

Same for the next level up (700mb) except the colors are a little weaker ...

And there's really very little going on in the middle troposphere (500mb)...

These all show that her structure is not really circular like a storm, but elongated like a front with two areas of stronger activity, which we can also see in a larger satellite image of the Atlantic:

The vorticity maps also show that she doesn't extend high into the atmosphere, so she is, indeed, a fairly weak system compared to a hurricane. But as a front, she can still bring some wet and windy weather... and it looks like she will to those in the UK area! Best put the deck chairs away!

<Technical Alert!> If you want to look at these maps for yourselves, go to the University of Wisconsin website for the Atlantic winds: http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=.

This will show you the map at 850mb. To look at the maps at the other levels, along the top are a number of tabs. Click on the level you want - 700mb, 500mb, 200mb.

These maps get updated every 3 hours, although you have to refresh the page each time. You can even go back to the map from 3 hours ago by using the tabs on the upper left. You can see a time stamp at the bottom, in the black border of the image.

There are a few more tabs at the top. Wind shear shows wind shear (are you surprised? ;-)). Wind shear tendency shows the direction the wind shear is heading in - so low tendency (dark blues) means that wind shear will not strengthen, and high tendency (reds and oranges) means that wind shear is likely to increase.

I'll go into upper level divergence and lower level convergence the next time we have a storm! (unless you have a super-amazing memory and really remember everything I ever wrote, in which case it is probably in an entry from last year :-)). <End Technical Alert!>

Meanwhile, over in the Pacific, we have TS Julio which has winds of 65mph and is still heading for the Hawaii region for the weekend, just a couple of days after Hurricane Iselle ges there (she has weakened to a cat 2 with winds of 100mph... I'm sure that's a relief to those on the islands!)...

(And in the western Pacific, Typhoon Halong is now down to a cat 1 with winds of 90mph, heading for Japan on Friday).

If Bertha is not downgraded tomorrow, I'll be back with another update - although it will be a bit late in the day because I'll be watching that scientifically accurate upcoming movie, Into the Storm (and then recovering from it). ;-) Otherwise, I'll back for the next storm (next name in the Atlantic is Cristobal) but I'll be tweeting about the other basin storms as usual in between.

Night night!
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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Hurricane Bertha: August 4, Update A

I'm going to jump right in today...

The NHC upgraded TS Bertha to Hurricane Bertha this morning. I think they overestimated her intensity and although she is still officially a hurricane, I have to say, I don't think she's been one for most of the day and certainly doesn't look like one now...

Currently her wind speed is 75mph, so she's barely a cat 1 (cat 1 range: 74-95mph). Central pressure is 1001mb. Although it looked like she was going to hang out in conditions that would allow her to grow a bit, she moved rather quickly over colder water! So although the wind shear is low and she's in an area where there is moisture in the atmosphere, we see the importance of the ocean at play... the sea surface temperature is around 27-28 deg C but there is hardly any warm water with depth; water warmer than 26 deg C is only in the upper ~25m. This would account for her scraggy appearance and structure.

She is apparently centered at 31.3N, 73.1W heading NNE 20mph. I really think she's a Tropical Storm and barely got to hurricane strength today. Of course she will continue to deteriorate as she moves north.

<Science Alert!> Although satellite images are one piece of the information puzzle, the biggest clue about what sort of storm we have is in the circulation (or vorticity as this is supposed to be all sciency stuff ;-)) and what that looks like at different levels of the troposphere - this gives us a glimpse into the structure of the storm. A tropical storm will have a well-defined circular "splodge" (yes, you can expect only the most highly technical jargon to be used here! ;-)) on a map of vorticity. The stronger the storm, the more cohesive the "splodge" at all levels of the troposphere.

Luckily for you, I have a Tale of Three Storms to show you this! :-) 'Hurricane Bertha' in the Atlantic, and both Hurricane Iselle and Tropical Storm Julio in the E. Pacific. Earlier today I grabbed the vorticity maps for the Atlantic and E. Pacific. At that time, Bertha was a cat 1 storm officially with winds of 80mph, Iselle was a cat 4 and had winds of 140mph (she is still a cat 4, but with winds of 135mph, still heading to Hawaii) and Julio was just a baby with winds of 45mph (he now has winds of 60mph, and is also heading in the Hawaii direction!).

We can see the how good the structure of these storms are throughout the troposphere by looking at the circulation/vorticity maps for four levels of the troposphere.

The lowest level, pretty darn tootin' close to the surface of the planet (850mb)...
Atlantic (Bertha, the really dark red splodge just to the right of the Bahamas):

E. Pacific (Iselle is the red 'splodge' on the left - actually, the center is white which indicates that the vorticity is really really strong - and Julio is the one on the right):

A bit higher (o.k., 700mb if you want to be all technical ;-))...
Atlantic (Bertha, the  dark red splodge next to the Bahamas):

E. Pacific (Iselle is the red/white 'splodge' in the center and Julio is the red one on the right):

The middle bit of the troposphere (500mb)...
Atlantic (Bertha, the not-so-dark-red-as-the-lower-levels-of-the-troposphere splodge next to the Bahamas, which indicates that although there is some vorticity, it is weakening as you get higher into the troposphere):

E. Pacific (Iselle is the dark red 'splodge' in the center and Julio is the one on the right):

And the upper troposphere (250mb)...
Atlantic (Bertha... no longer a splodge next to the Bahamas! which indicates no vorticity in the upper troposphere):

E. Pacific (Iselle is the round red 'splodge' in the center and Julio is no longer red splodge on the right):

For a hurricane, we always see a 'splodge' at all levels of the troposphere and they always line up on the same spot. The darker red the splodge is at the 200mb level, the stronger the storm. For a Tropical Storm, the vorticity generally stops somewhere in the middle troposphere (around 500mb), so both TS Julio and 'Hurricane' Bertha were really Tropical Storms, whereas Hurricane Iselle is most definitely a strong hurricane!

And thus endeth a Tale of Three Storms. :-) Let me know if you have any questions! :-) (All of these vorticity maps are from the University of Wisconsin... I'll show you how to get to them tomorrow). <End Science Alert!>

Before I zip off, I ought to mention this historic day... 100 years ago today (4th August, 1914) Britain and hence the Commonwealth jumped into The Great War, also known as World War I... or the largest family squabble in history (and you thought 'Dynasty' was bad?). Amazing times with many courageous stories!

Toodle pip!
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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Tropical Storm Bertha: August 3, Update A

A lovely Sunday with tea and Jaffa cakes and classic Dr. Who (the first one with the third Doctor, John Pertwee, is really good by the way :-)).

Meanwhile, over in the Atlantic things have also been moving along as suspected... Tropical Storm Bertha is still a Tropical Storm but has, indeed, intensified and now has winds of 65mph (1007mb central pressure). To re-cap from yesterday, this is because she's moved away from land (including the soggy Bahamas), wind shear has decreased (although there is still some), she's moved out of the dry and dusty SAL, and sea surface temperatures are now 28-30 deg C with waters warmer than 26 deg C.

She is not very organized at the moment but it looks like she will get stronger because all those conditions remain the same for the next day or so (wind shear will weaken a bit) and she'll probably be a weak hurricane tomorrow, which is in agreement with the NHC.

She is currently at 24.9N, 73.2W heading NNW at 17mph. The track looks more-or-less ok and she'll stay away from the US and Bermuda, possibly clipping Canada as a weaker storm in a few days:

So that's the Atlantic. Meanwhile, in the Pacific we have a few interesting things going on... the best looking of which is Hurricane Iselle, heading for a vacation in Hawaii on Thursday/Friday. She currently is a borderline cat 2/cat 3 (cat 2 range: 96-110mph, cat 3: 111-129mph) storm with winds of 110mph:

And in the West Pacific, Typhoon Halong is supposedly a border-line cat3/cat 4 storm because it has winds of 130mph, and is therefore stronger than Iselle. Although it is bigger, it does not have a very well-formed eye at the moment so I suspect it may be a bit weaker than a cat 4! (maybe a cat 2):

Not to be outdone by Iselle, Typhoon Halong is going for a vacation to Japan on Thursday/Friday. Japan really does not need more rain this week... I heard some parts had about 40 inches this weekend!

This large difference in the intensity of the storms (relative to their look) is because agencies from different countries issue the forecasts for storms in different parts of the world. Because they don't have enough data (or even the same sort of data) from inside these storms when they are over the ocean, it's pretty tricky for them to figure out their intensity (not for me, obviously, but I use magic ;-)  and I've been doing this for yonks!).

There are a few other blobs and blobettes in the Pacific, but that's all for now folks!

Until tomorrow,
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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Tropical Storm Bertha: August 2, Update A

Itsy bitsy Bertha is barely a Tropical Storm. She could be downgraded to Blobette Bertha and hardly anyone would notice, but officially the NHC have kept her as a Tropical Storm with winds of 45mph, central pressure at 1010mb as a precautionary measure. They said they couldn't find a center of circulation (or closed circulation actually)... and neither can I - can you?:

(Sorry about the satellite video loop - can't be helped!)

She does have a bit of convection though, with maybe the odd thunderstorm or two (shown as dark orange patches), as you can see in this infrared satellite image:

I received an on-the-ground report from our intrepid reporter, Tom, in St. Thomas:

"Short update from St. Thomas...first drop of rain at 6:41am with expectations of 6" by days end. Newly cleaned empty cistern awaiting the incoming...gusty wind but nothing like St. Croix to our south must be getting. Cats are in their hurricane beds behind hurricane shutters dreaming of gold fish and swooping birds...Bertha is a breeze!"

Bertha is currently officially centered at 18.9N, 69.1W, heading WNW at 22mph. This is somewhat speculative because, as I said, no-one actually knows the center. She is weak for three reasons:
1. She is interacting with the Dominican Republic, Puerto Rico etc. as shown in the satellite images, and this interaction will weaken her a bit more.
2. She is also in that area of dry, dusty Saharan Air Layer that I showed you yesterday.
3. There is quite a bit'o'wind shear.

The convection is because the water is rather warm - sea surface temperatures are 28-30 deg C, and the upper 100-125 m is warmer than 26 deg C.

Her future intensity depends on how much she weakens as she crosses out of the Caribbean. It is possible that she will begin to strengthen again as some of those inhibiting factors go away... you can see that she is almost out of the dry SAL layer and is moving towards a low-pressure area which has already got convective activity (over the Bahamas) in this IR satellite image:

Wind shear also looks like it will weaken once she is in the Atlantic, and the water temperatures are as warm as those in the Caribbean. All things that will allow her to intensify. The track keeps her away from the US, but it looks like she will roll over the Bahamas (who are already getting a coat of water).

I'll be back with more on Itsy Bitsy Bertha tomorrow!

Ciao!
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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Tropical Storm Bertha: August 1, Update A

I had a terribly busy week doing important things like painting my nails and drinking glasses of wine, but finally I have a moment to write!

I saw that the NHC upgraded a blobette to TS Bertha yesterday. I remember the last Bertha, 6 years ago... Big Beautiful Bertha. This Bertha is definitely not so big or beautiful at the moment. She's a dinky little thing with winds of 50mph (central pressure is 1007mb) and not much circulation or convection...

She is now in the Northeastern Caribbean, having crossed the Lesser Antilles earlier today, and is heading towards Puerto Rico. She is currently moving WNW at 24 mph (scampering along) and is currently at 15.2N, 61.9W (ish). The track forecast looks good to me.

The convection is to the north and east of the center, as you can see, so it looks like you guys in the VIs might finally get a spot of rain. Good news, hey? Just bring the cats indoors... apparently some of them don't like water. ;-)

Although sea surface temperatures are a rather warm 28-29 deg C, with warm waters in the upper 100-125m, I don't think she will intensify much in the next couple of days because there is some nice wind shear and she is still moving in oodles of dry and dusty air (known as the Saharan Air Layer) which you can see in this image as the lovely orange 'stuff' (technical term ;-)):

<Really Obvious Jargon Alert!> Saharan Air Layer (SAL): This is dry dusty air blowing off northern Africa (the Sahara Desert to be precise, in case the name didn’t give that away ;-)) and usually inhibits storm development. <End Really Obvious Jargon Alert!>

Once she moves away from the SAL and away from the Puerto Rico 'landmass' area, then she may intensify a bit more. Although I'm estimating this will take a couple of days, she is moving quite fast so we may see some intensification later tomorrow/early Sunday.

Good luck out there! More tomorrow.

Toodle pip!
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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