Satellite images:

05 February 2002:  UTC:  00 03    06 09    12 15    18    21

Port Hedland Radar
 

05 February UTC 20:10 20.20   20.30 20.40   20.50 21.00   21.10
06 February          01.00  01.10   01.20  01.30   01.40  01.50   02.00

Threat map

Mark Lander

Dear TC group,

    An intense TC made landfall on the northwest coast of Australia at
approximately 2000 UTC 05 FEB.  This TC was quite intense, perhaps a
Saffir-Simpson CAT 4.  It came ashore between the towns of Pardoo and
Wallal Downs.  The attached Enhanced IR at 1730 UTC 05 FEB, and an SSM/I
85 GHz image at 2138 UTC 05 FEB shows this intense TC as it moves ashore.

    Reports from the Perth TCWC indicate coastal crossing at 2020 UTC,
with a central min pressure estimated at 940 hPa.  JTWC intensity was 125
kt 1-minute sustained.

    Hopefully this hit a portion of the coast that was unpopulated.

    Regards,  Mark Lander
 

Grant Elliot
Hi

I've place the gif's for the best vis pic and the most intense dvorak IR (DT
6.5, 915 hPa,max wind 290 km/hr)  for TC Chris below:

                TC Chris 5 February 2002 (CLICK FOR FULL SIZE GIF'S)

            0830 IR                                                        0830Z vis                                                1430 IR
                                                                                                                                            (DT 6.5, 915 hpa,
                                                                                                                                          max wind 290 km/hr ?)
No correspondence will be entered into over central pressure estimates for
midget TC's, or for the appropriateness of  this Dvorak analysis !

Given that it moves over "desert" country during Wednesday it'll be interesting
(?) to watch the spin down process to see whether lack of surface moisture,
surface roughness or shear wil be the dominant destructive mechanism.

TC spin down rates would make such a great research project ........

Grant

Grant Elliott

Manager, Services Development
Bureau of Meteorology, Perth. WA.

Noel Davidson
G'DAY Grant,

We agree that TC spin down (and up) is a wonderful research project. (For that matter so are genesis and extra-tropical transition). We are currently using the Australian Region best track data,(thanks Jon Gill) NCEP and local analyses, and various LAPS configurations (thanks all involved) and diagnostic programs (thanks GM) to look at both rapid intensifiers and fillers. Initially to simpilfy the complexities we are concentrating on events over open ocean regions, and those
where the intensification begins from a relatively weak storm. We hope to then move to sea-coast-landfalling systems.
Below is a list of storms from the past 10 years we are considering. [Interestingly many of the rapid intensifiers are also rapid fillers.] If you/anyone have comments on these storms or wish to have input into the project or wish to get your hands dirty with the work - Let us know. We know you're busy though.

One of the main issues is how best to separate out the environmental flow changes from the effects of the storm intensity change. Obviously in the real world (and in complex models) one obscures the other. We think the only way to make the separation is by using the model. So we are running a hierarchy of successively-more complex systems to try and isolate the two.  I believe (probably like most forecasters) that the greatest variations in intensity are related to evolving storm environment.  But it is tricky isolating this process, particularly for intensification, where you mostly see the vortex intensifying and the storm outflow. Interpreting the dynamics of the environmental flow changes (thanks Baz) and their impact on the circulation are then other issues.
Comments welcome.
ND

From: Brueske Kurt Capt HQ USAFA/DFP <Kurt.Brueske@usafa.af.mil>

Subject: Wow...

Folks -

     I've attached a bitmap of the observation trends for Marble Bar which,
according to the NRL track image (also attached), came within 8nm of ground
zero.  Data provided by AFWA.  Sustained winds of 155KTS!  If someone could
forward this on to the tropical email group, I'd appreciate it.

KB

James Franklin

I notice that the station elevation is about 600 ft, so the 155 kt report  is
not as impressive as it seems.  Don't know what the terrain around this station
is like, though.

James
--
James L. Franklin

Hurricane Specialist, National Hurricane Center
NOAA/NWS/Tropical Prediction Center
11691 SW 17th Street, Miami FL 33165

Chris Cantrell

Dear TC Group,

One should be very suspect of the report of 155 knots at 0400Z from Marble
Bar in the AFWA decoded obs screen capture provided by Kurt Bruske this
morning.

The following wind direction and speed observations from Marble Bar were
passed to me by the PERTH TCWC office this morning:

The last report obtained from the station by PERTH before the storm hit was
on 6 Feb at 0358Z with the station reporting Winds:  110 degrees at 35
gusting to 55 knots.
At this time communications were cut between PERTH and Marble Bar.

When communications were restored the next observation received from Marble
Bar was on 6 Feb at 0759Z with the station reporting Winds:  020 degrees at
34 knots gusting to 47 knots.

Raw synoptic reports from station 94315 (Marble Bar) indicate the following:

at 06/01Z Winds: 090 at 70 knots
at 06/04Z Winds: 110 at 80 knots
at 06/07Z Winds: 050 at 80 knots
at 06/10Z Winds: 360 at 30 knots
 

SNAU94 KAWN 060100 RRC
AAXX 06014
94315 11430 80970 10221 20219 60344 76266 885//;
SNAU94 KAWN 060400 RRX
AAXX 06040
94315 41405 81180 10223 20223 76566 885//;
SNAU94 KAWN 060700 RRE
AAXX 06074
94315 11456 80580 10232 20223 60751 76266 885//;
SNAU94 KAWN 061000
AAXX 06104
94315 41556 83630 10232 20220 75052 885//;

vr,
Chris Cantrell

Jeff Kepert
G'day all

Terrain is pretty flat around Marble Bar - the land basically slopes up  gradually
from the coast 100 km or so away, with only small hills to break the monotony.
The place is named after a water-polished band of some stripy rock (not marble, but
maybe Jasper? - I'm no geologist) across a usually dry river bed (probably not
at the moment). Its main claim to fame is that it holds the Australian record for
the most consecutive days over 100 F - I don't remember the details but I think it
was over 100. I stopped in there briefly once while flying around the north-west in
a light aircraft in January ... my abiding memory is of the flies. To remember  them
15 years or so later I guess they must have been really something, but I reckon
they've all blown away now - for a day or two, anyway.

Jeff
 

From: Chip Guard <Chip.Guard@noaa.gov>
To: Jeff Kepert <J.Kepert@bom.gov.au>
Cc: James.Franklin@noaa.gov, Chris Velden <chris.velden@ssec.wisc.edu>,
    tropical-storms@tstorms.org
Subject: Re: [Tropical-storms] [Fwd: Wow...]

Jeff,

I have not been following TC Chris closely, but personaly, I'm really impressed  with
155 kt winds--and that far inland.  What I'm really interested in is how the  wind was
measured.  Did an instrument actually measure it?  Were these peak winds or
sustained winds? I would expect all but concrete/brick structures to be demolished if
they were sustained.  Any damage reports?

Chip
 

Date: Thu, 7 Feb 2002 10:44:25 -0700
From: Brueske Kurt Capt HQ USAFA/DFP <Kurt.Brueske@usafa.af.mil>
To: Chip Guard <Chip.Guard@noaa.gov>, Jeff Kepert <J.Kepert@bom.gov.au>
Cc: James.Franklin@noaa.gov, Chris Velden <chris.velden@ssec.wisc.edu>,
    tropical-storms@tstorms.org
Subject: RE: [Tropical-storms] [Fwd: Wow...]

Hi Chip -

     AFWA suspects that the 04Z Marble Bar AAXX report was encoded
incorrectly ('0' designator for wind speed in ms-1 was used whereas a '4'
designator should have been used for wind speeds measured in kts.)  As a
result, an 80kt wind was converted (based on the '0' designator) to 155kts.

Cheers,

KB

Jeff Kepert
Chip

I'm pretty sure 155 kt would be an Australian wind speed record - which as I
recall currently stands at 144 kt  set in Cyclone Vance in March 1999. I think Kurt
Brueske's theory of a coding error is likely correct. In any case, all winds in
Australian synops are 10 minute means (in theory, at least) and are usually reported in knots -
further supporting Kurt. Most (all?) of our synop stations now use cup anemometers,
apart from some of the official tropical coastal stations which also have a reinforced
high-speed Dines which is now used only in cyclone events.

Jeff
 

Jeff Kepert
More on the Marble Bar wind obs ... then I promise to stay out of your
hair.

Apparently there are two stations there, an AWS and the post office.
While the former has an anemometer, the latter (which gave the 80 kts)
estimates the wind.

I imagine, without wishing to criticise anyone, that most cooperative
observers would have very limited experience with such winds and that
the uncertainty would be correspondingly large.

Thanks to Terry Skinner for the above information.

Jeff

Barry Hanstrum

Folks

Just to set the record straight attached are the Automatic Weather Station
Observations from Marble Bar recorded during TC Chris on 6 February 2002 (a
summary of these is below).  The cyclone crossed the northwest coast of
Australia some 100 km to the north of Marble Bar at 2020UTC 5 February
2002.  This area of the Australian coastline is very sparsely populated
.  There was severe damage to the roadhouse at Pardoo and to nearby Pardoo
station, but thankfully no loss of life or injuries.

Regards

Barry