Atlantic blobette: September 27 Update A

Wind shear and dry air took their toll on the tropical depression, and
it's now just a...er... blobette again. Some things do go away if you
ignore them I guess. ;) There's still some circulation and convection, so
I'll keep an eye on it, but don't anticipate much. This is my last entry
on this system. Back to napping for now.

Ciao,
J.

Disclaimer: see previous update.

Atlantic Blobette: September 25 Update A

Ha ha ha... Did you really think you'd not be hearing from me again this
season? Well, better luck some other year. This year you can blame it on
El Nino. Which, coincidentally, I hear is (yet again) apparently solely
responsible for this 'quiet' season (according to my sources in the US).
Sigh. Before we even knew we were going into an El Nino (in the Pacific)
the signs were set up for a weaker season: for example, Atlantic water
temps were cool as I said at the beginning of June. There is also a lot
less water vapor in the air over the Atlantic (partly due to that Saharan
Air Layer also mentioned in an earlier entry), and there are a number of
other things afoot (and even aloft :)). The biggest influence on storms
over the Atlantic is, surprisingly, what's going on in/over the Atlantic!
What an amazing concept!! I'm a genius aren't I? I should be given an
award. ;) I'm not saying that El Nino has no impact, it's just not the
only one, and not the biggest. (And sarcasm aside... of course I'm a
genius ;)).

So, back to the Atlantic. There's a little blobette west of the Cape Verde
Islands. It's been struggling to get a grip for the past day, but
circulation isn't very strong. Convective activity has been waxing and
waning all day. I more-or-less agree with the NHC on this one. It is a
tropical depression (8th of the season), and is teetering on the edge of
being a Tropical Storm. But it is under reasonable wind shear given it's
size, and more importantly, has a lot of dry air around it, which will
inhibit it. The NHC site says something about how it'll also move over
cooler waters which will keep it down. I don't agree with that bit. It's
over temps of 28 deg C, moving over 27 deg C. Brr, yes cold indeed. Huh.
It's colder than that here when the sun is in full bloom. That water is
warm enough to sustain a storm. Should this storm manage to get a bit more
organized, the next name is 'Grace'. It's currently at about 15.4N, 31.5W,
moving NW at 14mph. Wind speeds of 35 mph, central pressure is 1008mb.

I'll try and check in over the weekend but if I don't manage to sober up,
not to worry as it'll stay in the Atlantic for now. ;)

Toodle pop,
J.

DISCLAIMER: These are just my opinions and thoughts, and not those of any
organization I represent. That should be obvious as organizations are not
generally prone to chit chat like this. If a storm is looming, please pay
attention to the NHC, weather service and your emergency managers because
they have the most up-to-date information.

Blob Fred: September 13 Update A

I was too busy having cups of tea with cucumber sandwiches to write an
update yesterday, but Fred declined and is now a blob again. There's still
a fair bit of convection, but circulation is now really only in the lowest
part of the troposphere. I'll check in on him, but don't expect much. So
this is my last entry on this system.

And the answer to the Famous Fred was Fred Allen. Thanks to LS for sending
me the details. Fred Allen wrote that about Boston in a letter to Groucho
Marx in 1953.

Mid-September... this week is the statistical peak of the Season.

That's all for now folks.
Cheerio,
J.

No Disclaimer Today. :)

TS Fred: September 11 Update A

As expected, Fred has been detiorating all day and was just officially
downgraded to a TS with winds of 70mph, estimated central pressure 987mb.
I think that was his status a few hours ago, and he's weaker than that
now. Although sea surface temperatures are still 27-28 deg C (ideally we
need at least 26.5 deg C or warmer to sustain a storm), the wind shear
took it's toll. It's difficult to see his center from satellite images
(which is why I think he's weaker). Officially the center is at 18.1N,
34.6W, and he's wandering NE-ward at a whopping 2mph. Obviously that's
just an estimate by the NHC. I think they are guestimating his center and
speed, because I took their 11am location and speed and did a quick
quackulation (like a calculation, but you make duck noises as you do it
;)) and the 5pm numbers don't match. But it's just academic really, as he
won't be a storm for very long.

A lot of you got the answer to yesterdays question: Freddie Mercury. How
did we survive without google? ;) (although some of you know some of these
sans help which impresses me as I can't even recall jokes I've heard
multiple times).

Famous Fred quote of the day: "I have just returned from Boston; it is the
only sane thing to do if you find yourself up there." Hee hee hee. Which
Fred?

Have a lovely Friday evening!
Toodles,
J.

Disclaimer: see previous entry. One day I'll follow my own advice and then
re-write it here.

Hurricane Fred: September 10 Update A

Well apparently there are more Scooby Doo fans out there than Fred
Astaire! Yes, yesterdays Famous Fred quote was from Fred in Scooby Doo,
Fred Jones (thanks D.P. for telling me his surname... saved me having to
look it up). :) Todays quote is at the end of this update.

Hurricane Fred is a Cat 1 now, with winds of 90mph (cat 1 range: 74-95mph)
and central pressure of 975mb. He's currently at 17.3N, 35.1W, casually
sauntering northwards at 5mph. The track forecast has him turning WNW in a
couple of days. I don't have enough data, so I'll go along with this. He
has slowed down, and looks like he might slow down even further in the
next few hours. As I have mentioned before, things become trickier to
forecast when storms slow down or stall because conditions around them can
still change. But as expected, he is now in greater wind shear from the
southwest and is looking very lopsided, with convection mainly in the
northeast quadrant. He may not even survive in such conditions.

<science alert> why would a storm stall? This goes back to the large scale
atmospheric pressure fields I was waffling on about a couple of days ago.
Imagine the storm is a ball. If the path ahead of it is low pressure (in
meteorological jargon you may hear "trough" or other such words), it's
like a downhill gradient and the ball will happily keep on rolling. But if
the path in front of it has high pressure, it's like an uphill gradient.
If it is 'uphill', the ball will slow down, or maybe move in a different
direction until it finds an easier path. But if it is in a 'dip',
surrounded by high pressure, then it's difficult for the storm to move in
any direction, so it will stop until the pressure fields around it change.
Of course, as pressure fields change, the forecast track will change even
though the storm may not have moved far. So not only do forecasters need
to predict the track of the storm, but they need to predict the entire
surrounding pressure field and how it will change before the storm moves
again. That's where the computer models really kick in. <end of science
alert>.

Famous Fred quote of the day: "I always knew I was a star, and now the
rest of the world seems to agree with me." Which Fred? :)

Have fun!
Tally ho,
J.

Disclaimer: read previous entries.

Hurricane Fred: 9/9/09 Update A

Fred became a major hurricane (cat 3) this morning, with winds of 120mph
(cat 3 range: 111-130mph), but has decreased in intensity since then.
Although the NHC's 5pm advisory still had him as a cat 3 with winds of
115mph, I think he's a cat 2 at the moment (cat 2 range: 96-110 mph)
because his eye is not very clear anymore, and the convection is a bit
skewed. His western side is a little weaker than the east, because he's
pulling in (entraining) dry air from the north and west. Also, his
northern side is beginning to move into an area of stronger wind shear.

He's currently centered around 14.8N, 33.3W, with central pressure of
960mb. The NHC had an interesting tidbit in their write up earlier
today...according to their records this is the strongest storm to have
formed so far south and east. There are a few caveats you should keep in
mind if you hear this: 1. Hurricane records only began in 1851; (2) a
storm like this would probably not have been detected before the 1970s,
when satellite observations kicked in and there are more, and different
types of satellite data available now which allow for greater accuracy
(hopefully!!); and, (3) techniques to estimate the winds and pressure of a
storm from afar have changed a bit over the years.

He's moving NW at 13 mph. I'm going to rely on the models and NHC for
track for the next 24 hours because the models are in pretty good
agreement at the moment and unless you are a mid-Atlantic jellyfish
<insert creature of choice>, I don't think small variations in track
forecast will matter. :)

Wind shear increases at about 18N, although sea surface temperatures will
still be over 27 deg C at that latitude. I agree with the NHC that the
shear will take it's toll and reduce intensity. But they claim a secondary
effect will be the reduced sea surface temperatures, whereas to me a more
likely secondary effect will be the surrounding dry air.

Famous Fred quote of the day: "Let's split up gang." Which Fred? :)

Night night,
J.

Disclaimer: Insert from previous entries.

TS Fred: September 8 Update B

TS Fred is still a Tropical Storm, but barely. His winds are now 70 mph
(TS range: 39-73 mph), with central pressure estimated to be 990mb. Also
as expected, he's continued on a westward track all day, with the forecast
having shifted west a bit. He's currently moving at 14mph and is centered
somewhere around 12.1N, 29.8W. Although wind shear is low and sea surface
temperatures are high, and his circulation (vorticity) covers most of the
troposphere now (essentially indicating a hurricane), he has been taking
in some dry air - part of the Saharan Air Layer I wrote about a while ago.
This has kept convection down a bit, but it won't be enough to stop him
from being a hurricane.

He'll keep going westish... He does have some room to move WNW, but it'll
only be a little. Then it looks like he will slow down as there is high
pressure ahead of him at the moment. In this I agree with the NHC.

<science alert> In the northern hemisphere 'things' (technical jargon ;) )
tend to move clockwise around high pressure systems, and counter-clockwise
around low pressure systems. For example, a tropical storm has low
pressure so winds move counter-clockwise (or anticlockwise if you prefer)
around a storm. Similarly, tropical storms also move around larger
pressure systems. There is generally a high pressure that likes to hang
out over the Atlantic, sometimes called the Bermuda High or the
Bermuda-Azores High. You can imagine it as a big clock face over the
Atlantic. As storms cross the ocean, they move westward along the six
o'clock region. As they turn WNW and NW they are moving from 6 to 9. Then
they move N and NE, from 9 to 12. Of course, this imaginary clock face
isn't nice and round, nor does it stay in the same place (otherwise
forecasting the track would be easy peasy :)). It's like a Dali clock,
with wiggly bits (more technical jargon ;)) that are always moving. That
is why I talk of 'pressure fields' when I talk about the track - I refer
to the large scale atmospheric pressure fields. <end of science alert>

I hope I didn't confuse anyone (well, not too much anyway :)) but of
course, if you have any questions don't hesitate to ask! I'll do my
bestest to explain what I know ... and can always make up what I don't. ;)

The answer to the Famous Fred quote earlier today was, indeed, Fred
Astaire. Another one tomorrow.

That's all for now folks.
J.

Disclaimer: no need to worry about this storm...insert disclaimer from
previous entries here.

TS Fred: September 8 Update A

I hope you had a "yaba daba doo" Labor Day weekend in the US. :) This year
Mother Nature also took a break. But yesterday a blob in the far eastern
Atlantic developed into a Tropical Depression, and now we have Tropical
Storm Fred. He's just SE of the Cape Verde Islands, centered at about
11.8N, 27.3W and is moving west at 15mph. He's so far east that he doesn't
yet appear on the NHC satellite page under the 'Atlantic Wide View'. Hmmm.
Maybe it's time to rename that to the 'Almost Atlantic Wide View, Just
Excluding That Bit Off Africa And Around The Cape Verde Islands, Which
Surely Aren't All That Important For Tropical Storms Anyway'. If you want
to see him, scroll down to the 'Eastern Atlantic', under Meteosat-8 (which
is a different satellite than the GOES images that cover the rest of the
Atlantic.

Winds speeds are estimated to be about 50mph, although they estimate his
central pressure to be 1000mb. Those two numbers don't quite match up in
my head - I think wind speeds are a little higher. Sea surface temps are
about 28deg C. He will grow. Circulation is quite well developed,
extending quite high in the tropopause (lowest 10-15km of atmosphere) for
such a little storm. Wind shear is low, so there is plenty of room for
convection to develop. The cloud tops are alteady cool.

The forecast track shows he will be moving WNW any second now, and then NW
in the next day or so. Why bother forecasting tracks via the western
Atlantic when you can save time and effort by forecasting them all to come
directly to the UK, huh? ;) I think he'll remain on a more westward track
than the 5am advisory shows, for now at least. There's a high pressure
system that he (like all storms) is moving around. I'll write a
bit'o'science about pressure systems in the next update later.

Famous Fred quote:"Chance is the fool's name for Fate". Which Fred? :)

Until later!
J.

Disclaimer: see earlier entries.

Blobette Erika: September 4 Update A

Erika made a valiant attempt to reform today, resulting in some strong
convection mostly over the water in the Caribbean, but to no avail. She's
back to being a blobette and this will be my last entry on her. Unless she
gets a second wind :) as she hangs out in the Caribbean.

There's another blob, way out by the Cape Verde islands. Not much
convection yet so we can tune out for the weekend at least.

Enjoy your long weekend! (we had one last week in the UK).
J.

Disclaimer: Not much out there to disclaim about. Hurray!

TD Erika: September 3 Update A

Poor Erika took a bit of a beating as she crossed the leeward islands and
has lost a lot of the big convective activity. She's well and truly in the
Caribbean now, with her center of circulation continuing to remain west of
the convection. A plane located it at 16.6N, 64.7W earlier today and the
latest NHC advisory has it at 16.7N, 65.3W, moving west at about 12mph,
with a central pressure of 1007 mb. She's been downgraded to a Tropical
Depression with winds of 35mph.

Although she's over water temps of 29-30 deg C, wind shear is strong. I
got a message from TJ in St. Thomas this afternoon. They were wondering
where the storm had gone as all they had at that point was a cloudy sky.
She's south of the VIs at the moment, and the convection is east of
that... so still to come if there's anything left. As I said, the
convection decreased in intensity and size thanks to the leeward islands,
so the VIs may get off lightly. The winds are mostly on her east, but all
warnings have been discontinued.

Worth keeping an eye on her, but with wind shear I'm not sure she'll be
anything big. Another fine example of those innocent looking islands
taking the steam out of a storm (puns always intended). As with life, it's
the little things you have to watch out for. ;)

I'll send out another update tomorrow. Have a super evening!
Night night,
J.

Disclaimer: See yesterdays. :)

TS Erika: September 2 Update A

She's not a very strong storm and she's a bit discombobulated which makes
it a little tricky seeing exactly where her center of circulation is. The
NHC had it at 16.2 N, 61.1 W at 2pm. I think it might be a bit west of
that, possibly already in the Caribbean. Her convection, which has
remained east of the center of circulation, decreased over the past few
hours. My theory is that it decreased as her center interacted with the
leeward islands. She's moving west at 10mph. I think her convection will
continue to decrease as she continues to cross those islands. I know they
only look like blips on a map, but we've seen them take the steam out of
storms in the past (all puns intended :) ).

Currently they have her winds at 40 mph, making her barely a TS (range:
39-73 mph). Central pressure estimated to be 1008 mb. A plane is heading
into the system to assess conditions. I don't have good pressure fields,
so I can't comment too much on the track. But from what I've seen, I'd
agree that she'll resume her WNW motion, essentially catching as many
islands as she can before getting to the Bahamas, including the VIs. She
may not be much by the time she gets that far though.

The other factor that's playing a role is the wind shear, which as I
expected, has increased. I am not sure what data the NHC are looking at,
because they said wind shear increased sooner than expected??!? I thought
we were looking at the same thing. Hmmm. Well I'm sure the plane will get
us all caught up. With disorganized storms like this, the forecast is
tricky, partly because it's difficult to find the center.

If anything unusual is found, I'll send out another update. Otherwise
tomorrow it is. I know that folks were scrambling to get boarded up
earlier today on the islands, partly because of the belated notice and
partly because the track shifted closer towards them than expected. Let
me know how things are out there if you can.

Toodle pip!
J.

Disclaimer:
These remarks are just what I think, and I could be totally off my rocker.
So if a storm is approaching, please heed your emergency managers, the
NHC, the weather service as they have more up to date information. If I
was hypothetically there, I'd let you know if I was going to 'run away,
run away' (Monty Python) or stay put and have a glass of wine instead.

TS Erika: September 1 Update B

Well I don't think anyone who is near the path of this storm is
particularly surprised by the NHC finally getting around to recognizing a
tropical storm. And if anyone is reading this from the NHC, I can tell you
that there are a lot of people who are not happy bunnies and were
wondering earlier today if you had fallen asleep on the job! TS Erika has
sustained winds of 50mph and a central pressure of 1007 mb. Quite a jump
from the 'high probability of a system forming' to a ready-made mid-sized
storm with tropical storm force winds extending 105 miles out from the
center don't you think?

She's moving WNW at 9mph and is at 17.2N, 57.3W. As with the storms that
preceeded her, she'll most likely barely skim the leeward islands and head
towards the east coast of the US. As I said earlier in the season er...at
least a whole two weeks ago...storms that form close together tend to
follow a similar track because the pressure fields don't change that
rapidly.

It doesn't look like she'll be too big. The NHC agree with my earlier
statements... The circulation center is slightly west of the convection,
she's experiencing some wind shear and heading into more Wind shear etc.
TS watches have been issued on the northern leeward islands.

More tommorrow! Be good. Be safe.
J.

Due to technical difficulties, the disclaimer should be here. Insert from
a couple of entries ago. C'est la vie.

Atlantic Blobette: September 1 Update A

If you are on one of the Caribbean Islands, and it's a bit overcast,
that's because you have the outer edges of a tropical system overhead. The
NHC have not yet upgraded it to a Tropical Depression, but i think they
should have earlier today. It looks like a Tropical Storm to me (next is
Erika I think). They have sent a plane on this afternoon to confirm or
deny all such rumours.

Circulation has been good all day, and convection has been really strong
for the past couple of days. If it's any consolation, I think the center
of circulation may be west of the main convection. Also, the circulation
is currently confined to the lower part of the troposphere, so it's a weak
system. And finally, in favor of keeping it small, it's moving into an
area of slightly stronger wind shear. Of course, water temperatures are
over 29 deg C. The cloud tops are very cold, indicating some very strong
thunderstorms.

I hope you guys have your umbrellas ready!

Maybe the NHC have been distracted with Hurricane Jemina, who was just
downgraded to a cat 4, and is in the eastern Pacific, about to hit Baja. I
hope she gets some rain to the southern California wildfires. Wouldn't
that be handy? I got this from a friend who lives in Pasadena:
"I can see the fires from my street. Air quality is BAD. I do not go to
the Burbank office because I do not want to breathe the air..."

Wind picked up today here, from the remains of TS Danny I presume. Another
blustery and wet day tommorrow I expect. I suppose I ought to pay
attention to the weather one of these days ... ;)

I'll send out another update if the plane finds a Tropical Storm swirling
away out there.

J.

Insert disclaimer from the previous entry here.