Topic: Tropical Cyclone Hamish : Queensland from March 5 2009

[Colin Maitland]

Cyclone Hamish is continuing his track down the southeast coast at 10 Km/h. He is moving in a south easterly direction.
The statistic gathered fromBOM are:
Hamish is still a  Cat 4 cyclone with winds up to 240km/h. he has a centre of 945HPa.
He is located 230Km north-northeast of yeppoon at 4.00 am this morning.
The track map does not show any suggestion that he will cross the coast in the next 48 hours.

[Jimmy Deguara]

Hi,

I am interested in the current decision making patterns and refer once again to the fear of storm surges. Here is the quote from the ABC news website entitled -"Wide Bay residents advised to flee Hamish's destruction"

"We're asking people in that storm surge area to self-evacuate and we're hoping they'll do that before midnight on Monday," he said.

This is the real threat given so many people live in low lying areas. Even a category 4 can pack a significant storm surge.

More on storm surges

Here is an example of storm surges from http://www.extremestormsurges.com
http://www.youtube.com/watch?v=LyKl4lz3mzg

Please continue the focus on the discussion on tropical cyclone Hamish - the video is just an example for education purposes.

Regards,

Jimmy Deguara

[Colin Maitland]

I feel there could be a considerable amount of complacency with evacuation of low lying areas, and especially with self evacuation. I say this after reading the headlines of the latest ABC article,"Hamish weakening, unlikely to make landfall" the article quotes "Weather bureau forecaster Ann Farrell says the system has weakened and is not likely to make landfall at all."

Although, these may be the facts, I think there is a high possibility that many are going to feel well be right. The bureau has still warned that there is exceptional high tides with this system, so tidal or storm surges could still be a major concern for many areas. People need to stay alert and listen to all warnings, and have an evacuation plan in place.

The ABC article quotes Ann Farrell from the BOM, "The situation's looking much improved on how it was during yesterday, but we're still not out of the woods and we should remain vigilant," she said.

"There is a slight chance always with these things that they can move in towards the coast.

The latest Stats from BOM on Hamish

Details of Severe Tropical Cyclone Hamish at 7:00 am EST:
.Centre located near...... 21.8 degrees South 152.2 degrees East
.Location accuracy........ within 28 kilometres
.Recent movement.......... towards the southeast at 12 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 945 hectoPascals

All the stats at this stage, don't seem to show any signs off a weakening system, Need to keep an eye on the updates to see what is happening


Update, BOM have issued a severe warning for Synoptic Situation:
Severe Tropical Cyclone Hamish was located 320km east southeast of Mackay,
moving southeast at 10 km/h.

Severe Tropical Cyclone Hamish is generating large southeasterly swells about
the central coast of Queensland. This is expected to cause dangerous surf
conditions and inundation above the normal high tide level about exposed coastal
areas and islands between Proserpine and St Lawrence around the high tide this
morning.


Colin

[Colin Maitland]

The latest stat from BOM for Hamish at 11.00am EST.

Details of Severe Tropical Cyclone Hamish at 10:00 am EST:
.Centre located near...... 22.1 degrees South 152.6 degrees East
.Location accuracy........ within 28 kilometres
.Recent movement.......... towards the southeast at 14 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 945 hectoPascals

He remains much the same at this stage, but if you are wondering how the Dvorak rating is used, that John Allen was talking about, the following site (pdf file) explains it. http://www.nhc.noaa.gov/pdf/06velden.pdf

[Colin Maitland]

Since midday, my wife and I have been hearing reports and even watched 2 news breaks ( make that 3, as I was writing this another report came through) saying they have down graded Cyclone Hamish. Only the chance of him making landfall has been downgraded, and I think some have misunderstood what BOM  meant by that. They only give Hamish a 5% chance to make landfall.

The 2.00 pm advice has been released and Hamish, besides positional changes is still a CAt 4
From the BOM

Details of Severe Tropical Cyclone Hamish at 1:00 pm EST:
.Centre located near...... 22.5 degrees South 152.9 degrees East
.Location accuracy........ within 28 kilometres
.Recent movement.......... towards the southeast at 15 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 945 hectoPascals

It was of interest that the State govt this morning was going to do a mass evacuation from Hervey Bay, by bus and train, to bring residents to Brisbane and other places. That has been put on hold. It seemed to be a feeling that they can relax now, the storm is not going to affect them.

They did interview one Hervey Bay resident, who had been through several cyclones, and she stated,"  these storm are unpredictable, you look after yourself and if you feel you have to go, you go".

I will know from living in QLD for 42 years, seeing and being through several cyclones, and we used to track them for the surf,  you never take them for granted. Every storm is different, and no computer model will show you exactly what the system will do.

But I really do hope they are correct, they only give Hamish a 5% chance to make landfall, we need the rain but not a Cyclone.

Looking at the track map Hamish looks like he going to do a complete 360 degree turn due to the high over the Tasman

[Richary]

System looks like it will fall apart, its forward motion is being retarded and its undergoing interaction with significant wind shear.

Hi John

Not arguing just wondering where you are getting the evidence for significant shear? The Brisbane and Rockhampton aerological diagrams aren't showing much shear. Though I admit I don't know how to interpret the shear diagrams on bsch.

Richard

[Colin Maitland]

Cyclone Hamish has not changed all day, they were sating by lunch he would be Cat 4, but tha thas not been the case. The warning is now curent right down to Tewantin, 5 minutes North of Noosa, or about 70 minute drive North of Brisbane.
The latest fromBOM at 5.00pm

A Cyclone WARNING remains current for coastal and island communities from
Yeppoon to Hervey Bay. A Cyclone WATCH remains current for coastal and island
communities from Hervey Bay to Tewantin.

Severe Tropical Cyclone Hamish, a CATEGORY 4 CYCLONE, is located off the
Capricornia coast and at 4:00 pm EST was estimated to be 255 kilometres east of
Yeppoon and 245 kilometres north northeast of Bundaberg, moving southeast at 17
kilometres per hour.

Severe Tropical Cyclone Hamish poses a threat to exposed coastal and island
communities between Yeppoon and Hervey Bay [including Heron, Fraser and Lady
Elliot Islands]. The cyclone is expected to maintain a southeast track parallel
to the coast during the next 24 hours. In the 24 to 48 hour period the cyclone
is expected to become slow moving and weaken slightly.

Details of Severe Tropical Cyclone Hamish at 4:00 pm EST:
.Centre located near...... 22.8 degrees South 153.2 degrees East
.Location accuracy........ within 28 kilometres
.Recent movement.......... towards the southeast at 17 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 945 hectoPascals

He just keeps plodding along down the coast. He has gained momentum again, travelling back to around 17km/h. He did slow down to around 10-13km/h this morning.
As I keep saying I hope he weakens, we do not want a cyclone, just some good rain

[Colin Maitland]

Tropical cyclone Hamish has continued his quest down the QLD coast last night, he is remained a CAT 4, has risen 1 HPa to 946HPa, and slowed his movement to 11 km/h. I have been wondering for the last day or so, that once he passes Fraser Island, the end of the reefs and hits the open water, if he will change course, today the bureau have suggested that "Severe Tropical Cyclone Hamish is expected to slow down and weaken during today.
It is then forecast to change direction on Wednesday morning and begin to move west towards the coast as a weaker cyclone."
I had read somewhere last night that they were thinking a CAT2 or high CAT1.

Once cyclone Hamish reaches open water, there will be no reef to break the impact of the swell, so it will be interesting to watch for wave heights on the wave buoys, Stradbroke island is usually an excellent  one to keep an eye on, if only they had held off the Roxy Pro for one extra week. Snapper Rocks or Kirra should be pumping if the system keeps edging a bit further down the coast.

STATS from BOM this Morning

Details of Severe Tropical Cyclone Hamish at 4:00 am EST:
.Centre located near...... 23.7 degrees South 154.1 degrees East
.Location accuracy........ within 19 kilometres
.Recent movement.......... towards the south southeast at 11 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 946 hectoPascals

This is one site for waverider buoys, http://www.epa.qld.gov.au/environmental_management/coast_and_oceans/waves_and_storm_tides/wave_monitoring/

The north Stradbroke comes under the Brisbane site and this norning has registered 3.6M

Col.

[joedan]

Can someone please explain the discrepancy between the BOM cyclone tracking, http://www.solar.ifa.hawaii.edu/Tropical/tropical.html and the JTWC map.

Both the Hawaii site and the JTWC map show Hamish tracking away from the coast where BOM shows it performing a loop.

Which one of these sites is more accurate, why is BOM so different?

[Colin Maitland]

To put in in simple terms or  language, from my understanding, they all run off computer generated models, using data collected over the decades of storms and weather patterns, they also calculate the variables for each day, eg, the current high we have over the Tasman today, the wind shear in the area, they use all the collected data from aerological readings etc, they compare statistics of the cyclone from yesterday to today, basically updating information all the time, from hour to hour, or if there is a significant change, they see if it is intensify or weakening, ( more technical language and understanding refer to http://www.nhc.noaa.gov/pdf/06velden.pdf, ) they put this all together, recalculate the systems movements, and try and predict what Hamish will do.

Hamish, and all cyclones are completely different, they may have similarities, but every storm is different. He is allowed to do whatever he wants. He may stall, regenerate and head for land, he may weaken and form into a rain depression, or may just head out to sea and fizzle out. They are, to a high degree unpredictable.

So any one of those sights could be correct, but BOM is using current data gathered from sources close the the cyclone and have updated there track path to what technically should happen right now. BOM would also be scrutinizing every movement due to it being in our waters.

Hope this helps. Just in basic form. Someone else, will probably provide a better or more detailed understanding.

[JRees]

I would suggest that the Bom's track is more reliable as it is being updated every 3 hours compared to the JTWC who are only issuing track maps every 12 hours

[Colin Maitland]

Cyclone Hamish has been downgraded to CAT 3 at 11.00am today.

The official word from BOM
Details of Severe Tropical Cyclone Hamish at 10:00 am EST:
.Centre located near...... 24.2 degrees South 154.8 degrees East
.Location accuracy........ within 19 kilometres
.Recent movement.......... towards the southeast at 11 kilometres per hour
.Wind gusts near centre... 220 kilometres per hour
.Severity category........ 3
.Central pressure......... 965 hectoPascals

They have issued a separate warning
TOP PRIORITY FOR IMMEDIATE BROADCAST
SEVERE WEATHER WARNING
for Damaging Winds, Abnormally High Tides and Dangerous Surf
For coastal and island communities between Sandy Cape and Coolangatta
Issued at 10:00 am on Tuesday 10 March 2009

Synoptic Situation: Severe Tropical Cyclone Hamish, a Category 3 cyclone, was
located  at 10:00 am EST to be 145 kilometres east northeast of Sandy Cape,
moving southeast at 10
kilometres per hour.

Severe Tropical Cyclone Hamish is expected to slow down further and gradually
weaken.

Damaging winds gusts to 90 km/h, dangerous surf conditions and abnormally high
tides  are expected over coastal and island communities between Sandy Cape and
Coolangatta over the next few days.

They have moved the Quicksilver Pro to snapper rocks today. In Brisbane it is starting to become very cyclonic in conditions. The wind is picking up quite considerably in the last hour. Cape Moreton has registered 93 km/h. Most of Brisbane is experiencing gusts up to 50km/h and intensifying.

It will be interesting to see what Hamish actually does from here. The track map has him doing a complete circle.

[Colin Maitland]

Cyclone Hamish at 11.00 am EST, is now a CAT 2 cyclone approx. 230 KM Northeast of Fraser Island according to BOM. He is now moving in a northwesterly direction, back up the coast. We will see what he decides to do over the next couple of days, but at this stage he does not seem to pose a threat according to BOM.

In the South east of QLD we have have severe weather warning in place due to a combination of cyclone Hamish and the high from the Tasman. Last night, the wind in Brisbane became quite calm, and today  we have had a few showers tending towards light rain. They were expected 80+ km/h winds today.

The Brisbane waverider buoy, positioned at Point Lookout at North Stradbroke Island is measuring 4.7M swells. Duranbah on the QLD/ Nsw border at the tweed river is registering 3.3M. You can check out the latest at http://www.epa.qld.gov.au/environmental_management/coast_and_oceans/waves_and_storm_tides/wave_monitoring/
   

Due to the large swell of SEQ coast we have had a unpleasant Chemical spill from a cargo ship. The following is a short extract taken from 9NSM article posted at 7.00 am this morning. It states regarding the mishap

{A cargo ship that spilled 31 containers of ammonium nitrate into Queensland's Moreton Bay in the wake of Cyclone Hamish has also leaked heavy fuel oil.

The Hong Kong-flagged Pacific Adventurer cargo ship was travelling from Newcastle to Brisbane in rough seas near Point Lookout at Stradbroke Island in southeast Queensland when the container spill happened about 3am (AEST) on Wednesday.}

[Richary]

With the forecast track now showing it weakening to a Cat 1 then a Low and heading back NNW, I am wondering about the chances of it picking up strength once again as it moves back to warmer waters where it formed?

[JRees]

I can not see it myself - allthough that said BOM are still reporting that it has winds of 40 knots