From:
"Mark A. Lander" <mlander@uog9.uog.edu>
Reply-To: "Mark A. Lander"
<mlander@uog9.uog.edu>
To: tropical-storms@tstorms.org
Date:
Thu, 27 Dec 2001 12:26:48 +1000 (GMT+1000)
TC group,
A very low latitude TC has
moved westward towards Singapore for the
past couple of days. This
TC exists at an unusually low latitude (around 2
north). It has had a nice
cloud signature for a while now (see the two
attached VIS images -image1,
image2)
and shows up well in the quikSCAT pass as nice
compact vortex (see attached
quickSCAT
pass valid at 2300 UTC 26 DEC).
Has Singapore (1.4N ; 104 E) ever been directly affected by a TC?
Regards, Mark Lander
Reply-To:
"Mark A. Lander" <mlander@uog9.uog.edu>
To:
tropical-storms@tstorms.org
Date:
Thu, 27 Dec 2001 14:34:45 +1000 (GMT+1000)
TC GROUP,
I looked at the TRMM MI,
and I think I see a typhoon at 1.6 North --
Incredible!! (see attached TRMM 85 GHz image at 0003 UTC 27 DEC). This will be one for the record books. JTWC has it as TS 32W on first advisory.
Regards, Mark Lander
From:
Roger Edson <r.edson@excite.com>
To:
tropical-storms@tstorms.org
Date:
Thu, 27 Dec 2001 00:52:49 -0800 (PST)
Hi,
I've got to add to this
one!!!
Here is the remarks straight
from the JTWC 27 Dec 0600Z warning (#2):
WARNING INTENSITY IS BASED
ON A SHIP OBSERVATION WITHIN THE PARTIAL
EYEWALL OF 75 KNOTS SUSTAINED.
A 270220Z3 SSM/I PASS DEPICTED A
(APPROX.) 15 NM EYE WITH
ASSOCIATED DEEP CONVECTION AND STRONGER
WINDS SITUATED OVER THE
SOUTH SEMI-CIRCLE. ANOTHER SHIP REPORTED
GUSTS TO 105 KNOTS WITHIN
THE SOUTHERN PORTION OF THE EYEWALL.
Of special note: this is
for those of you who always have a slight doubt
whether those 'microwave
eyes' really are the same as a 'good' visual or IR
eye....(my belief, if you
are lucky enough to be in the right time and
place, you will generally
get those hard-to-get verifications).
For those 'trackers' this
system seemed to form in conjunction with a surge
in the NE monsoon and pre-existing
cyclonic trough (equatorial trough) off
the northeast tip of Borneo
on the 24th (UTC).
(BTW, I know Charlie Holiday
wrote a MWR paper back in the 70s of a typhoon
at 2+ deg North...can anyone
beat this one?)
Amazing.
Roger
To: "Mark A. Lander" <mlander@uog9.uog.edu>,
tropical-storms@tstorms.org
From:
Sytske Kimball <skimball@jaguar1.usouthal.edu>
Date:
Thu, 27 Dec 2001 09:06:46 -0600
Mark,
This is fascinating! I lived
in Singapore as a child in the 1970s and certainly
I can't remember ever being
hit by a typhoon. But that was only a nine year span.
Does anyone know if Singapore
has ever been struck by a typhoon?
Thanks for posting.
Sytske
From:
"Goerss, Dr. James" <goerss@nrlmry.navy.mil>
To: "'Mark A. Lander'" <mlander@uog9.uog.edu>,
tropical-storms@tstorms.org
Date: Thu, 27 Dec 2001 09:31:49
-0800
It's also interesting to
note, looking at FNMOC's WXMAP web
page, that both NOGAPS and
the AVN appeared to have a pretty
good handle on the system
for the past 2 days. Looking at
the various length forecasts
of surface streamlines valid at
00Z, December 27, one can
see that both models did quite well.
Jim Goerss
From John McBride
I was tempted to post a message on this fascinating system before Christmas, but I was so busy that week drinking beer and doing other Christmas-type activities, I let it slide.
Anyway, there has been a
strong local cyclonic vorticity maxixmum in that location since 19 December,
more than a week ago (vort_19Dec_1200,
850_19Dec_1200) associated with a southchina
sea surge. The system didn't really spin up until about the 22nd
at which point you can see a strong vortex almost on the equator and of
diameter about 20 degrees lat/long (vort_22Dec_0000,
850_22Dec_0000, satpic_22Dec_0000)
As you probably all know,
the McBride-Zehr (J. Atos Sci, 1981) viewpoint on development was that
you require a large scale strong anticyclonic vortex in the 250-850 hPa
shear pattern. Looking at this for the 22nd, (shear_22Dec_0000),
you can see a very clear anticyclonic vortex with winds speeds of 20-40
kts just off Singapore, with easterlies on the equator, southwesterlies
to the north. Both of these features exist also in the 250 hPa flow (250_22Dec_0000).
I don't know what causes what; but from the 250 flow and the shear, it
was already a deep warm-cored system on the 22nd.
IF the forcing is partly from the upper levels, the localised equatorial easterlies are probably important. Looking at today's 250 hPa anal (250_27Dec_1200), these easterlies are associated with a southern hemisphere anticyclone to the south; and there is a strong hint this is brought about by cross-equatorial advection of positive earth vorticity air (IPV-350-28Dec-0000)
Also, while I'm here, to add to the nice pictures that Mark put up, I have included a couple of larger scale GMS pictures of the system on my website: (012280000_NW, 012270600_NW)
From Julian Heming
Roger,
I cannot trace the MWR paper
to which you refer, but have found a paper by
Holliday in the proceedings
of the 11th AMS conference on hurricanes and
tropical meteorology (December
1977) entitled 'A near equatorial typhoon'.
This refers to Typhoon Kate
(1970) which became a typhoon at 4.3N and
remained a typhoon equatorwards
of 6N for 3 days.
The only other case I can
find which comes near to Typhoon Vamei is Typhoon
Sarah (1956). This became
a TD at 1.7N and a typhoon at 3.3N. See Fortner
(1958) for more details.
I think it is fairly safe to say a lower latitude
typhoon has never been observed
than Typhoon Vamei.
Cheers,
Julian
Reference:
L.E.Fortner, 1958. Typhoon
Sarah, 1956. Bull AMS, 39, pp 633-639
---
Julian Heming NMC
Support & Tropical Cyclone Forecasting
Met Office London
Road Bracknell Berkshire RG12 2SZ United Kingdom
