Hurricane Isaac: September 30, Update A

As expected given the ocean temperatures and low wind shear, Isaac has
intensified. In the 11am NHC advisory this morning, he was upgraded to a
hurricane - the fifth hurricane of the season. The average number of
hurricanes per year is 6.

Maximum sustained winds are near 75mph (cat 1: 74-95 mph), so Isaac is
not a very strong cat 1. He is still moving fairly slowly at 7mph in a
northwestward direction.

He is heading into a region of slightly increased wind shear again, and
it looks like in a few hours he will start to interact with that low
front that I mentioned yesterday. He is still over water temperatures of
26-27 degs C and at his current speed and direction, he will be for
another day. So, there is room for a little more intensification in the
next 24 hours, but not too much. There is also a chance that he will not
intensify further - it's a battle between the ocean and atmosphere.

Not much more to say on this storm for now. All else is quiet out there
in the Atlantic.

In the Pacific on the other hand, Typhoon Xangsane killed 61 people in
the Phillippines (it hit the capital, Manila), and is now heading
towards Vietnam, due to hit there in a few hours. Typhoons are the same
as hurricanes, but that's the name for these tropical storms in the
western Pacific. This typhoon is about the same intensity as Isaac with
winds of 80mph, which makes it a mid-level cat 1 on our scale. But it
has already caused much havoc and mayhem in the far east - partly
because it hit a highly populated major city.

Until tomorrow.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

TS Isaac: September 29, Update A

Welcome to my new two-step program.

Isaac is becoming a little better organized, and he has also started to
move in a more westward direction. The problem with this change in track
is two-fold:
1. It brings him a little closer to land (not so much of a problem really)
2. It keeps him over warm waters (of 26 deg C), which may mean that he
will intensify a bit more than expected.

The westward shift in direction is because high pressure has developed
in front of him (see blog entry: Hurricane Gordon & Hurricane Helene:
September 16, Update A for why this would cause a more westward
movement). At the moment the models are divided as to how long this
west-north west motion will continue. There are two reasons for the
division in opinion:
1. They are trying to predict how long this high to the north of Isaac
will persist
2. There is a low pressure front moving eastward from the US into the
Atlantic, and depending on Isaac's speed, this will interact with the
storm and help him turn toward the north and then north-east.

Here's an image of the low front (band of clouds extending from the
north-east to the south-west off the US coast) and the storm:
http://www.ssd.noaa.gov/goes/east/nwatl/vis-l.jpg

By the way, this is the same low front that brought those chilly
temperatures of 83F (28 degs C) to Florida yesterday. Brrr.

Wind speeds within the system are 45mph (TS: 34-73mph). He is currently
moving along at a fairly slow 6mph (another indication that he's bumping
into high pressure). There is still dry air around the system, but he is
entering an area of weaker wind shear. So, there is room for some
intensification - between the shear and the warm water. Plus, as his
speed is quite slow, he will be over that warm water for longer.

Have a nice day,
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Tropical Storm Isaac: September 28, Update A

The latest National Hurricane Center (NHC) advisory at 11am upgraded the
latest Tropical Depression to a Tropical Storm Isaac. Winds are around
40mph (TS wind range is 39-73mph), so he's a very very weak Tropical
Storm. They are basing this on satellite data of winds and as it is so
close to the lower limit of TS force winds, this upgrade in status is a
judgement call in my opinion. I probably would have kept it as a TD for
at least another advisory... but that would have been boring and you
wouldn't have heard from me. :)

Isaac is a dinky little thing really. There is dry air in the center and
to the south and west within the area of rotation. There is also dry air
surrounding the system. He is currently over water temperatures that are
barely 26 degs C, and is heading into cooler surface waters. The
subsurface waters are not really conducive for intensification. There is
some wind shear and although he is heading into a region of less shear I
don't know if that will be enough to allow much intensification.

The path keeps him out in the Atlantic.

I agree with the NHC, this storm won't get above a mid-level TS, if that.

I'll only send out one update a day on this one.
J.

P.S. If you have any questions feel free to send me an email. I'll try
and "make up" an answer ;)

------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Tropical Storm Helene: September 25, Update A

She officially became a Tropical Storm yesterday morning. Not much to
say about her. Northern Europe can expect some windy weather and that's
about all.

This is the last entry on Helene. Nothing else is out there at the
moment... so over an out until the next one.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Helene: September 23, Update A

Well she's still a hurricane, and a good sized cat 1 at that, with winds
of 90mph. She's definitely over cooler waters, so now she's what I would
consider to be more extratropical than tropical, and therefore her
intensity is being maintained by the atmosphere more than the ocean.
Cloud tops are low, there is dry air well within the system - so she's a
windy thing with a bit of rain perhaps.

She's heading towards northern Europe. My brother told me this morning
that what was left of Gordon brought about 2 drops of rain but he did
make the surfers up there happy with the windy conditions at sea.

Assuming the other big blob (sorry about this highly scientific jargon I
keep using) in the Atlantic doesn't develop into anything, I think I'll
take the day off tomorrow. Have a lovely weekend.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Helene: September 22, Update A

She's picked up forward speed and is racing along at 21 mph now...
heading in the general direction of north Scotland (but that's still
days away). She'll be an extratropical system by then.

Her winds are at 85mph, so she's still a mid-strenght cat 1. But I
really expect her to weaken soon (24 hours) because more of the system
is in a stronger wind shear, she's moving over colder waters (25-26 degs
C), and dry air is being entrained into the system. As a reminder,
waters of 26 deg C are needed to sustain a tropical system (but not an
extratropical system). Her slight increase in wind speed since
yesterday's 80mph was from atmospheric effects, not because of the
ocean. The southern and western sides of this system looks pretty
ragged. The circulation in this storm is still quite strong, so she will
be a nice extratropical storm soon.

If you look at a satellite image of her now
(http://www.ssd.noaa.gov/goes/east/nwatl/vis-l.jpg) you can see a long
arm of clouds extending to the north. That was a low front that moved
westward (across the US and into the Atlantic) and has now interacted
with this hurricane.

That's all for today folks (unless the next system out there becomes a TS).
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Helene: September 21, Update A

Helene is barely a mid-sized cat 1 hurricane now, with winds of 80mph
(cat 1: 74-95mph) so it looks like the conditions I laid out yesterday
that would inhibit this system proved their worth. I don't think she
will re-intensify and in the last advisory the hurricane center also
brought down their intensity estimates.

She's moving at a pretty good 13mph now and will soon (in a day) be over
cooler waters. She is still entraining dry air, there is still some good
wind shear affecting her outer bands.

I think there's a good possibility that she will be a tropical storm by
this time tomorrow - although we are again looking at a storm that will
become extratropical. Really not much more to say on this at the moment.

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Tropical Storm Gordon & Hurricance Helene: September 20, Update A

Tropical Storm Gordon:
This system is weakening, and it's projected path suggests that it might
miss Spain but clip France as it heads to the UK. By the time it gets to
the UK it won't be very strong; just rain and some windy weather. So
really, no difference from usual weather conditions in England :)

Hurricane Helene:
She's still a strong cat 2 with winds of 110mph. She's made that
north-west turn, so it looks like she's following in Gordon's footsteps
and avoiding Bermuda. This system is still moving forward at a
medium-paced 9mph. The eye is no longer visible on the satellite
imagery. This might be a cycle the storm is going through, or it might
be the beginning of a longer (but slow) decline. There's a chance she
will intensify slightly, which would make her a weak cat 3 again. But,
there are clues in both the ocean and atmosphere that suggest otherwise.
These are:
1. Dry air is being entrained into the outer regions of this system.
2. Although she is over water temps of 28-29 deg C, the subsurface
depths at which 26 deg C water extends down to is declining, (which
means that the source of energy is being reduced) and will continue to
decline in the path that she is currently on.
3. She is entering a region of slightly stronger wind shear.
At the moment, these conditions are not strong enough to reduce her
intensity by much, but they are enough to possibly inhibit future
enhancement. At the very extreme, she'll get to a weak cat 3 for a short
time and then start a decline.

I'll only send out one update a day unless anyone knows anyone in the UK
in which case I can send out more frequent updates to those
interested... oh wait, that would be me... :)

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and Hurricane Helene: September 19, Update A

Special request: If you forward these emails to people, could you send
me an email letting me know approx. how many you forward them to (not
including yourself cos you are on the list). I'm just trying to get an
idea of the number of people who are being "forced" to read my rambles.
:) Oh... and if they are in different states, can you let me know which
ones. Thanks.
-----------------------------------------
Hurricane Gordon:
I turn my back on the Atlantic for one day and Gordon decides to head to
the nearest landmass as a cat 1 hurricane!!! He's not as well-behaved as
I thought he'd be. Well, it looks like the Azores will be hit by a
medium-sized cat 1 storm, with winds of 85mph and then after that he'll
head towards the northern edge of Portugal/Spain. The Azorians (? -
anyone know what they are really called?) are already under the cloud
bands. Gordon is moving directly eastward at a very fast 33mph so the
good news for the people on the Azores is that he will pass by very
quickly.

He's in a region of pretty good wind shear, and has been in temperatures
below 24-25 degs C for a day at least, and yet he has still hung on.
He's in the extra-tropics now (at almost 40 degs N) and therefore the
physics involved are different and the reason this storm is still so
strong is because of the atmosphere and not the ocean.

Hurricane Helene:
Helene has a well-defined eye and an almost circular shape. I say almost
circular because there is dry air to the south-west quadrant. She's
moving forward at a stately 9mph, with winds of 110 mph, making her a
strong cat 2 storm (cat 2: 96-110mph). The wind shear is quite low near
the center of the system, although the outer bands are in regions of
stronger shear. The eye is over some pretty warm waters (28-29 degc C)
and sub-surface conditions are favorable for some intensification. So,
as there is no friction to really dissipate the energy of this system
and she will remain in waters favorable for intensification, I agree
with the NHC, that there's a very good possibility that she will
intensify to a cat 3 again soon.

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon & Hurricane Helene: September 17, Update A

Hurricane Gordon:
He continues to be a very weak cat 1, but he has started moving to the
north at least although very slowly at 6mph. He'll be heading northeast
soon though, and I think he'll be a TS within the next 24 hours.

Hurricane Helene:
Helene did strengthen a bit since yesterday and is now a mid-level cat
1, with winds of 85mph (cat 1: 74-95mph). The system is moving towards
the northwest at 9mph. She's still in a low shear environment, the
water vapor situation is the same as yesterday, and she's over slightly
warmer waters. I expect her to continue to intensify, and maybe even be
a borderline cat1/cat 2 storm by tomorrow.

Speaking of tomorrow, I won't be sending out an update. If you are using
these blogs to figure out the date, it will be Sept. 18th tomorrow :)

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon & Hurricane Helene: September 16, Update A

Hurricane Gordon:
Yes, he's still a hurricane... but barely. Winds are near 75mph (cat1:
74-95mph). As he has been pretty much stationary overnight, the decrease
in intensity has been slow. Once he starts moving (and it looks like he
has slowly started in a northward direction - or maybe in a slight
north-northwestward direction but that could be a wobble) then he will
cross into 25 deg C waters - he's not far from that region so the time
it takes will obviously really depend on how fast he gets going. For
those who don't know, stationary or stalling means that the storm is not
moving forward.

Why would a storm stall?
Well, tropical storms are generally steered by mid-to-upper level
(around 4km-13km above ground) pressure systems. The storm will move in
a clockwise direction around a high pressure system in the northern
hemisphere. This is what Gordon has been doing for most of his life -
imagine a clock face... he started off moving in the 6-9 quadrant (i.e.
west-northwest), and when he made that northeast turn, he began moving
in the 9-12 quadrant. Clockwise motion. But high pressure systems are
not as nice and round and solid as a clock face would be (otherwise that
would make this forecasting too easy and lots of people would be out of
a job :) ). These pressure systems evolve with time (hence the changes
in the forecast direction). A storm will stall if high pressure develops
in the path of a storm. I tell people it's like a ball (storm) trying to
roll up-hill. If it has room, it will adjust and try and move around
this by moving in a more westward direction (clockwise) until it gets to
an area it can cross. But if there is no room for movement, the system
will stop where it is. These pressure systems are also partly why storms
move forward at varying speeds.

The converse to the high pressure systems are the low pressure
systems... I'll get into that another day when there's a storm that will
provide an example.

Hurricane Helene:
He-storms and she-storms are created equal... well, at this point in
time and only as far as max. sustained winds go because Helene and
Gordon are, indeed, at the same strength. Helene's sustained winds are
near 75mph too, making her just about a hurricane. But unlike Gordon,
who has had his day, she will grow some more and get stronger. She's
already much bigger in area than Gordon is. She's moving along at a
respectable 14mph

Helene is in 27-28 degs C water and will continue over that for at least
another day. This means she will slowly intensify. She's in an
environment of low-to-moderate wind shear, coming out of the north-west.
Although the direction of wind shear will change in the next day or so,
it doesn't look like it will get any stronger. As I said the past couple
of days, there is dry air around this storm (to the west and north), but
it really it doesn't look like it is reaching the center and therefore
won't have as big an impact as it has for other storms.

I'm glad she's moving in a more northwestward direction than before. Now
I have more confidence that she will stay away from most land. Whether
or not she will clip Bermuda though is still a question (in my mind).

Today I expect some slow intensification of this system, but probably
still within the cat 1 range.

I'm only posting one entry today as nothing much is going on out there
(ha ha ha).
More tomorrow morning.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and TS Helene: September 15, Update B

Not much time this evening but fortunately everything is progressing as
I expected:

Hurricane Gordon:
Now a cat 1 with 90 mph winds and still falling... He has stalled
however, but it shouldn't affect the system too much.

TS Helene:
She's intensifying and will more than likely be a hurricane by tomorrow
morning.

Sorry about the brevity... although I'm sure it makes a nice break for
you all :)

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon & TS Helene: September 15, Update A

Hurricane Gordon:

He's now a cat 2 storm and falling. The southwest side is getting eroded
(wind shear) and dry air is entering the system, the eye is no longer
visible although the center is still obvious, and cloud tops are
gradually getting warmer. He's still over water temps of 26 degs C.,
which will sustain him but not enough to intensify. He's in a region of
moderate wind shear, and is heading towards a region of increasing wind
shear. In a day or so, I would expect this storm to be down to a cat 1
at the most because of increasing wind shear and colder ocean temps. BUT
here's the catch, as with Florence, he might become an extratropical
storm in which case the physics are different, so it could be a storm
with strong winds even then.

TS Helene:

Not much change. Still a TS, max. sustained winds of about 45mph. She's
a large storm too, but just not very well organized. Waters are warm,
the wind shear is moderate. At the moment the cloud tops are quite high
for this storm, but that could be part of a cycle and may not be
sustained. There's a bit of dry air entering the system on the outer
edges, but it doesn't look like it's making it into the center. I think
this storm will start to get stronger soon.

And now for something almost completely different... some humor!
Regardless of your opinion on global warming, I hope you enjoy this:

http://ff.org/centers/csspp/library/co2weekly/20060906/20060906_14.html

It made me laugh.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and TS Helene: September 14, Update A

Hurricane Gordon:

He's still a big storm... there's been no change in the intensity since
this morning, although he will soon be over waters of 26 degcs C. There
is some wind shear as I said earlier, and which is keeping this storm
from growing any further. He is maintaining his status quo despite the
slightly cooler waters and wind shear because of other atmospheric
dynamics, because it's not the ocean. Actually, if it wasn't for the
wind shear and cooler temps, the other atmospheric conditions are ripe
for this storm to intensify further. He's still a good looking storm,
despite the shear. I'm attaching a photo so you can see the shear -
there are more clouds in the north-east quadrant. The shear is from the
south-west.

TS Helene:

Her forward sprint (22mph) has slowed down to a more respectable fast
jog of 16mph (o.k. so I'm not a runner... I guess that's more of a
really really fast jog!). Winds speeds are at 45mph (TS: 39-73mph), so
still not a very strong TS. But don't you worry, that will change and
she will grow. She's in an area of low(ish) wind shear, warm 28 degs C
water, and the center of this storm is not being exposed to dry air. She
is moving in a west-northwest motion, but I'm still going to wait a
couple of days before I have full confidence that she won't affect the
islands.

Oh, one more thing before I sign off. One of my good friends (being a
computer purist) insisted that if I'm calling this a 'blog', then I
should have a proper weblog - thanks Mr. H. :) So I'm proud to announce
the arrival of:

http://jyotikastorms.blogspot.com/ <http://jyotikastorms.blogspot.com/>

Some of these updates have already been archived in reverse
chronological order. If you're into blogs and RSS feeds and all that,
you can subscribe to the blog using your RSS reader (like Bloglines or
Newsgator) with this feed:

feed://jyotikastorms.blogspot.com/atom.xml

If you wish to be removed from the list and access the updates at your
leisure at the blog site instead, then please let me know. Also, while I
am saying thanks to my technical managers, I really need to thank Mr. V
for setting up and maintaining the list, ad Mr. D for offering to help
with maintaining it if needed. Proper thanks and full names will be
given at the end of the season. Assuming I can still type by then. :)

Ciao,
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and TS Helene: September 14, Update A

Hurricane Gordon:

Now a cat 3 with sustained winds of 120mph (cat 3 = 111-130mph), Gordon
is a mid-strength cat 3 storm. However, he is definitely beginning to
encounter some shear (from the south-west) to the north because the
northern side is looking a bit ragged and not as circular as the
southern part. The clouds tops are also warmer in the northern parts of
this storm compared to the southern part. The asymmetry could be part of
a cycle, but I doubt it. He still has a good eye though, and is still
symmetric closer to that center. He's moving forward at a faster pace
too (about 13 mph), and will soon be over waters of 26 deg C. Therefore
I think this is the strongest we will see this storm and I expect him to
have lower winds in the next advisory, and by the 5pm advisory he'll
might even be a cat 2. He is heading on a north-northeast track to nowhere.

Tropical Storm Helene:
Although Helene has a circulation, it is still difficult to pinpoint the
exact center of that circulation. There is a broad area that could be
considered to be the center. The convection around her is not very well
organized at the moment either, but there is a lot of water vapor in the
system already so the dry air outside won't be as important as it has
been in other storms. She is moving westward vey quickly, at 22 mph -
which is about as fast as any storm I remember. Her sustained winds are
about 40mph (TS: 39-72 mph) so she's barely a TS. All wind product sites
just went down, so the shear portion will have to wait until later. But
she's in pretty warm water (28degs C), which will help her to slowly get
her act together (depending on the wind shear).

More later...
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and TD 8: September 13, Update B

Right... I inadvertently put my foot in it in the last blog entry by
(a) calling Gordon 'cute' when he should have been 'handsome', and (b)
signing off 'later gators' which was supposed to be short for 'see you
later alligator' (something we even say in the UK), but in Florida
'gators' refers to the UF college football team which apparently has
some very very loyal supporters and some very very strong rivals. :)

Hurricane Gordon:

Gordon is a very handsome storm, with a very handsome eye and a very
handsome circular outflow. :) He's a strong cat 2 now, and is still
taking his time crossing that warm water. Combining the warm water with
very minimal wind shear, it does look like he'll become a cat 3
overnight. In his case, it was atmospheric conditions that allowed him
to become so very strong. So, he'll be our first 'major' storm of the
season. I'm quite happy that he's well behaved and will stay away from
land. He really is a beauty to look at in the satellite image and I'm
attaching a picture, taken from the GOES-East satellite for you all to
ooh and ahh at.

As for my comment about the model that overestimated the intensity of
this storm...I take it back (sorry Dr. A. ;) ). It looks as though this
model has the atmospheric component correct, but not the oceanic
component. But I believe my friend & his colleagues are working on
correcting that for next year. This model does have one of the better
track records for well... getting the track correct. :)

TD 8:

Thanks to this system, I found out something very interesting today.
Until today, this storm was so far in the eastern Atlantic that I was
looking in a different place for the satellite imagery (from Meteosat
instead of GOES-east which is my normal source). It looks like the water
vapor levels in the Meteosat image are much higher than the GOES image!
which is why I said yesterday there was hardly any dry air around this
system. Well TD8 is now visible in both satellite frames, and in the
GOES image there is plenty of dry air around this system and although it
doesn't look like much is being entrained, some is and that's helping to
keep the intensity down.

Not too much change since the last update. The storm circulation is
slowly improving (although no-one can find the center), and there is
more convective activity. It is still in pretty good wind shear, and as
I said there is some dry air, but given the warm water etc, there's a
good chance it will become a TS sometime tomorrow.

O.K.... later 'hurricanes' (I believe that's the UM football team)...
hmm... just doesn't have the same poetry to it, does it?
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Gordon and TD 8: September 13, Update A

Hurricane Gordon:

Gordon became a cute little hurricane overnight. I say 'cute' because
he's already moving towards the north and will hang out in the Atlantic
ocean, he has a nice circulation, and a nicely developed eye. His
sustained winds are near 90mph, which makes him a strong cat 1
(74-95mph) - and also means he intensified slightly faster than I
thought. The eye will be over slightly cooler waters of 27 degs C in
12-24 hours (currently in about 28 degs C) - he is not moving forward
very quickly (9mph). He will remain in a region of some wind shear but I
don't think the it is enough to stop him developing further. There will
be some intensification during the day, and it is possible that he will
become a cat 2 by the end of the day. If he stalls anytime in the next
48 hours, then there's a chance he will become even stronger.

TD 8:

Although this storm doesn't look as good as it did yesterday (i.e. i
can't find the center anymore), the circulation within the system has
improved. It is over warm waters (28-29 degs C), but that alone won't
be enough to make this intensify because it is also in a region of good
wind shear. Sometime in the next 24 hours I expect this to be a TS
because the wind shear will decrease, the ocean will be more conducive
to development. It's moving westward at a fast pace (17mph). The
forecast track has it going out to sea and staying north of the Leeward
Islands - this is still days away and I will have more confidence in
this in a couple of days.

Later gators.
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

"Hurricane" Florence, Tropical Storm Gordon & Tropical Depression 8: September 12, Update B

One...too...many... storms....too...much... to...talk...about.
Just skip to the one you are interested in (but I wrote this so it
*must* be a fascinating read ;) ) ...

Also... in case you fall asleep by the end... TD8 is the one to keep one
eye on as far as we are concerned - although there is a chance it will
also recurve out to sea. But it's not yet even a TS yet.

"Hurricane" Florence:
This is no longer a tropical system because it is over colder waters now
and the interaction between the ocean and atmosphere is not the same, so
it is now an extratropical system. Winds are "near 75mph" and this is
still a big storm (in size). Cloud tops are very warm, there is dry air
all around the eye, there is huge wind shear etc. The NHC are no longer
putting out advisories on this system after the 5pm advisory today.

This is the sort of storm that meteorologists argue over whether or not
to even call a hurricane because the physics that maintain this sort of
system is very different from a tropical system. Therefore the
"hurricane" classification is based on wind speed alone, which is a bit
dodgy in my humble opinion. :)

This also highlights one of the many problems with the historical record
of hurricanes - in the old days this wouldn't be classified as a
hurricane. However, in more recent times the way storms are defined has
changed. Fortunately a project is currently underway to try and bring
the historical hurricane database onto a more even platform (there are
many many other problems with the database in addition to this one).
After that is done (sometime in the next year or two hopefully), then
studies that look at changes in hurricanes (e.g. intensity) over the
past x number of years will have a more solid footing on which to base
their claims.

How many paragraphs can I start with the word 'This'?

Bye bye Florence.

Tropical Storm Gordon:
As I said earlier, TS Gordon has colder cloud tops than Florence. I
should explain that colder cloud tops means that the clouds are 'deeper'
and there is more convective activity. In the troposphere (the layer of
the atmosphere closest to the ground, the temperature gets colder with
increasing height - think of climbing a mountain and how it is colder
the higher up you go). I could actually work estimate how much higher
the tops are compared to Florence, but that might just throw you all
over the 'science threshold' (and in case you haven't figured it out by
now, yes, I'm a science geek and proud of it). :)

It has become better organized since I looked at it earlier in the day.
But it is still a TS. Sustained winds are 65mph, so some intensification
since earlier. It is heading due north, but not very quickly at a mere
7mph. Over the next 24 hours the ocean conditions are good for some more
intensification, the wind shear is low, and I don't think dry air will
be a player for now. This will probably be a hurricane by this time
tomorrow. But not a cat 2. One of the models has it as a cat 2 in three
days. This model has been over-intensifying storms all season as far as
I can remember. The NHC seem to have picked up on this and are placing
less emphasis on it as they did at the beginning of the season, so the
NHC forecast has the intensity as a strong cat 1 in 2-3 days. I think
this is far more reasonable.

TD 8:
Hot off the coast of Africa, this system is not even a TS and I can see
the center of circulation. The good news is that it is heading into an
area of higher wind shear. The bad news is that it is in an area of lots
of atmospheric moisture... hardly any dry air in sight. It's moving
westward at 15mph. Sustained winds of 35mph (TS=39-73mph). Temperatures
are 28 degs C, and on its westward path it will soon (24-36 hours) get
to 29 degs C temps. So I expect some intensification over the next 24-36
hours. This will be TS Helene (I had to look that up :) ).

Current model track forecasts have it remaining far north of the
Antilles. It's too soon to tell I think.

Stay tuned for more tomorrow ...
J.

------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Hurricane Florence & Tropical Storm Gordon: September 12, Update A

"Hurricane" Florence:
The 5am advisory said that Florence was still a cat 1 hurricane with
winds of about 75mph. Cat 1 storm winds: 74-93mph. So it's nominally a
cat 1 and that wind speed is within all sorts of error margins
(instrument, satellite algorithm etc). Since then, this storm has fallen
apart even further. Cloud tops are much warmer and there is dry air in
the center of the storm. I consider this to be a Tropical Storm, and it
was probably a TS at 5am too, but as I mentioned for umm... TS Ernesto I
think, it is the NHC's job to be conservative and that is o.k.

I do not see any reason why they would keep it at the cat 1 designation
at the next advisory (11am). I will send out a brief note on this once
it gets officially downgraded, but other than that, this is my last real
update on Florence.

Tropical Storm Gordon:
Cloud tops in Gordon are actually colder than for Florence. He is much
smaller in areal extent compared to Florence. I agree with the forecast
track, which takes this out to sea. The good news for Bermuda is that he
will pass to the east.

As with most TS, I can't see a well defined eye. Wind speeds were last
noted to be about 60mph (TS range: 39-73mph) so this is a mid-intensity
TS. He is currently over water temps of about 28 degc C (minimum temps
required for tropical cyclogenesis is 26 degs C - tropical cyclogenesis
means 'development of a tropical system'), but given the track and speed
he is moving on, he will move over cooler waters (about 26-27 degs C
temps) within the next two days, which is enough to sustain the system,
but not really help to develop it further. However, he is in a low
shear environment at the moment and although there is dry air around the
system, I don't see it being entrained. So I think this will intensify
to maybe a strong TS/weak cat 1 and that's about it. This is
more-or-less in agreement with the NHC forcast. I'll only send out one
update a day on Gordon unless I see anything unusual.

That's all for now folks. :)
J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.
------------------------------------------------------

Natural disasters & Hurricane Florence: Sept. 10 Update B

Earthquakes felts whilst writing hurriance blog this morning: 1
Hurricanes discussed during hurricane blog this morning: 1
Tsunamis in the Gulf: 0

As I was writing the blog this morning, I heard a loud bang and then
my desk shook and computers rattled/slid slightly. I thought some
plane or ship had crashed at first, and my second thought (as the
shaking was going on) was that it was an earthquake. But I've never
felt one here, so I dismissed that thought and continued merrily with
the blog. An hour later, I heard that it was an earthquake.

According to early reports, there was a magnitude 6.0 earthquake in
the Gulf of Mexico, just over 250 miles WSW of Tampa Bay at 10.56am
this morning. It's the largest in the Gulf for about 30 years. No
reports of damage or casualties. Pretty cool that I felt it as I
usually end up sleeping through these things. It was about 6.2 miles
deep (10km) and in a supposedly non-active geological region (i.e.
not on a fault). I don't know much about this, so maybe one of the
experts on geology in the the Gulf of Mexico who are reading this can
fill me in on the details and I'll pass that email along to this
list? I know I'm interested, and I'm sure others will be too.

Hurricane Florence: not much change... still moving in the same
direction, the intensity has increased to 90 mph, so although it is
still a cat 1, it is approaching cat 2. More later on this.

J.
------------------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms
(my storm blog). If you are making an evacuation decision, please
heed your local emergency management and the National Hurricane
Center's official forecast. This is not an official forecast.
------------------------------------------------------