TC STEVE (14P) PART #2 - GULF OF CARPENTARIA - REPORT

28th February to 1st March 2000

By Carl Smith

carls@ace-net.com.au


Note: see TC STEVE (14P) PART #1 - DIRECT HIT ON CAIRNS - REPORT for the first incarnation and TC STEVE PART #3 - TOP END and WESTERN AUSTRALIA - REPORT for the third incarnation of this rather unusual cyclone.

REPORT

After hitting Cairns as a Category 2 cyclone, degenerating, and crossing Cape York as a tropical low pressure system, ex-TC Steve central pressure (CP) 1002 hPa (hectoPascals = millibars) with max. wind gusts to 80 km/hr (45 knots = KT) was moving west-southwest (WSW) at 20 km/hr (11 KT) overland near 17.5 South (S) 141.5 East (E), that is near Normanton southeast (SE) of the Gulf of Carpentaria, at 5pm CST Monday 28th of February (280730 UTC) when TROPICAL CYCLONE ADVICE NUMBER 1 (TCA#1) was issued by the BUREAU OF METEOROLOGY (BoM), DARWIN, saying a CYCLONE WATCH has been declared for coastal and island communities between Mornington Island in Queensland and Alyangula in the Northern Territory. If the low continues its current track over land cyclone development is unlikely. However there is some possibility that it will start to move towards the northwest, with the risk of a cyclone developing Tuesday night or Wednesday in the southern Gulf of Carpentaria.

By the time TCA#2 was issued at 11pm CST (281330 UTC), ex-TC Steve 1000 hPa had changed direction and was moving west-northwest (WNW) parallel to the coast at 20 km/hr (11 KT) over water in the SE Gulf of Carpentaria near 16.9 S 140.8 E, about 75km (40 nautical miles = NM) northwest (NW) of Karumba.

A rather confusing situation developed in the early hours of the morning of Tuesday the 29th when BoM Brisbane issued FLASH TCA#1 at 3:10am EST [2:40am CST] (281710 UTC) saying a Cyclone Warning has been issued for coastal and island communities between Mornington Island in Queensland and Alyangula in the Northern Territory.

A cyclone (or potential cyclone) in this area is in Darwin's area of responsibility, however Brisbane BoM had jumped in and issued it's own warning. I feel that to avoid confusion it would have been far better for Brisbane BoM to have got on the phone to Darwin BoM and urged them to issue a FLASH warning as soon as they realised the situation had changed rather than going ahead with preparing and issuing their own warning. Whilst it did not matter that much in this case due to the early hour, having two TCWC's issuing public warnings could create real confusion in the media who are responsible for delivering warnings to the public, and so generate public confusion, which is undesirable in these situations.

This was soon followed by FLASH TCA#3 issued by BoM Darwin at 3:26am CST [3:56am EST] (281756 UTC), which was quite similar to the Brisbane warning, saying at 3 am CST [3.30 am EST] a low [ex-tropical cyclone Steve] 993 hPa with wind gusts to 100 km/hr (55 KT) and intensifying was located near 16.8 S 139.7 E in the SE Gulf of Carpentaria just SE of Mornington Island moving WNW at 20 km/hr (11 KT). The low is expected to reform into a category 1 cyclone in the next few hours and continue moving to the NW parallel to the coast.

TCA#4 was issued by BoM Darwin at 5:08am CST (281938) and then TCA#5 at 8:00am CST (282230 UTC), when the system was again named Tropical Cyclone Steve, 990 hPa, saying it had redeveloped and was located near 16.5 S 139.2 E in the SE Gulf of Carpentaria near Mornington Island moving WNW at 15 km/hr (8 KT). GALES with gusts to 120 km/hr (65 KT) are currently being experienced between Mornington Island and the Queensland/NT border.

AJTWC resumed issuing warnings (#005) at 282100 UTC saying that at 281800 UTC it was near 16.9S 139.7E moving 290 degrees at 08 KTS with max. sustained winds of 25 KT gusting to 35 KT and in the remarks that at 282100 UTC it had regenerated and was near 16.7S 139.3E just SE of Mornington Island with a CP of 995 MB.

Both centres continued issuing warnings throughout the 29th as Steve continued moving parallel to the southern coast of the Gulf of Carpentaria, with not much of note beyond a slight deepening of CP to 988 hPa in TCA#6 issued at 11am CST (290130 UTC).

It should be noted that there was an increasing divergence between BoM and JTWC positions and direction of movement, illustrated by JTWC #007 issued at 292100 UTC saying that at 291800 UTC Steve was near 15.1S 137.3E moving 310 degrees at 08 KTS with max. sustained winds of 45 KT gusting to 55 KT, and in the remarks saying at 292100 UTC it was near 14.9S 137.0E continuing to move NW over the southern Gulf of Carpentaria. TC 14P is over open water with high SSTS and upper level outflow is good to excellent in all quadrants. Compare with a BoM shipping warning issued at 291930 UTC saying at 1800 UTC TC Steve 988 hPa centred within 30 nautical miles of 15.6 S 137.4 E moving W at 7 knots. Sustained winds increasing to 50 knots this morning within 30 nautical miles of centre with very rough to high seas and heavy swell. Sustained winds 35/45 knots within 60 nautical miles of the centre.

TC Steve intensified as it approached Port McArthur as noted in TCA#13 issued at 8am CST (292230 UTC) Wednesday 1 March saying TC Steve CATEGORY 2 985 hPa with wind gusts to 130 km/hr (70 KT) and intensifying was located near 15.6 S 136.9 E in the SW Gulf of Carpentaria 40 km ENE (22 NM) of Port McArthur and 190 km (100 NM) ESE of Port Roper and 195 km (105 NM) SE of Numbulwar. The cyclone is moving west at 12 km/hr (6 KT), closer to the coast. It is expected to cross the coast between Port McArthur and Port Roper around the middle of today. DESTRUCTIVE WINDS with gusts to 130 km/hr (70 KT) currently near the centre may be experienced between Port McArthur and Port Roper as the cyclone crosses the coast. GALES with gusts to 120 km/hr (65 KT) are currently being experienced along the coast between the Northern Territory/Queensland border and Port McArthur and should extend further along the coast south of Numbulwar during the morning.

Steve crossed the coast near the delightfully named Bing Bong at 11:00 am CST (010130 UTC) as noted in TCA#14 saying TC Steve CATEGORY 1 988 hPa with wind gusts to 120 km/hr (65 KT) was located near 15.6 S 136.4 E in the SW Gulf of Carpentaria 35 km (19 NM) NW of Port McArthur and 140 km (75 NM) SE of Port Roper. The cyclone is moving W at 12 km/hr (6 KT) and has weakened slightly. It is currently crossing the coast near Bing Bong. One could speculate that Bing Bong is named after the call of a particular frog!

Steve was slowly losing intensity after the coastal crossing as seen in TCA#15 - at 2.00 pm CST (010430 UTC) Tropical Cyclone Steve CATEGORY 1 990 hPa max. wind gusts to 110 km/hr (60 KT) has crossed the coast in the SW Gulf of Carpentaria and is now located near 15.6 S 136.1 E, 55 km (30 NM) WNW of Port McArthur and 125 km (65 NM) SE of Port Roper. The cyclone is moving west at 11 km/hr (6 KT) and will remain adjacent to the coast. GALES with gusts to 110 km/hr (60 KT) are currently being experienced along the coast between Port McArthur and Port Roper and should extend further along the coast towards Numbulwar during the day.

It had weakened to 992 hPa with gusts to 100 km/hr (55 KT) moving W at 13 km/h (7 KT) by 5pm CST (010730 UTC), and the (second) final BoM warning was issued at 8:00 pm CST (011030 UTC) Wednesday 1 March 2000, saying ex-TC Steve 995 hPa with wind gusts to 70 km/hr (40 KT) was located near 15.7 S 135.0 E over land about 150 km (80 NM) W of PORT McARTHUR and 115 km (60 NM) SSW of PORT ROPER, moving W at 15 km/hr (8 NM). It has WEAKENED below tropical cyclone intensity and GALES are no longer expected on the Territory Coast. HEAVY RAIN is still expected to cause widespread flooding of low-lying areas in the eastern Top End and Roper-McArthur region tonight and tomorrow.

AJTWC issued it's (second) final warning (#008) for TC 14P Steve at 010900 saying at 010600 UTC it was near 15.4S 135.1E moving 285 degrees at 09 KTS with max. sustained winds 25 KT gusting to 30 KT and was dissapating over land, and in the remarks said at 010900 UTC it was near 15.4S 134.8E.

EXTRA INFORMATION

Extract - TC Steve - Observations from Mark Kersemakers at Darwin.

29 February - 3 MArch 2000

Centre Island reported gales for two hours 2030-2230 Z 29 Feb 2000 as the cyclone approached and passed just to the north of the AWS. Gales did not resume as the cyclone moved passed and approached the coast

Max mean wind speed was 38 knots (with 46 knots gust) at 2224Z. Max gust was 50 knots (with mean ws of 37 knots) at 2145Z.

The cyclone moved across Bing Bong port Office after passing Centre Island. They reported a lowest pressure of 987 hPa but mean winds no more than 20-25 knots either side of the calm (estimated from white caps on water visiable from office). They observed a calm for 45 minutes prior to about 11 am 1 March.

<snip>

----- Note from Mark ------
Centre Island (station no 94248) is located near 15.74S 136.80E.
Bing Bong Port is near 15.63S 136.39E.

<snip>

NOTES:

Note 1: Tropical Cyclone Advices, Updates, and Shipping Warnings used as sources for meteorological information in this report were issued by the Australian Bureau of Meteorology (BoM) Brisbane Tropical Cyclone Warning Centre and are Copyright Commonwealth of Australia 1999, Bureau of Meteorology - http://www.bom.gov.au. BoM information is used unless otherwise noted.

Note 2: BoM Brisbane issues warnings to the Australian public using kilometers for distances, kilometers per hour for maximum gust wind speeds, hPa for central pressure, and times are EST, which is Australian Eastern Standard Time = UTC + 10 hours. I have converted all these and added in them brackets, so changing to nautical miles (nearest 5 NM), knots (nearest 5 KT), hPa = MB, and times are also given in UTC.

Note 3: Joint Typhoon Warning Center (JTWC), Pearl Harbour, and Alternative Joint Typhoon Warning Center (AJTWC), Yokosuka, Japan, (JTWC had temporarily relocated to Yokosuka, Japan, for a cyclone conference) tropical cyclone warnings were also used for extra meteorological information where indicated, and that material is copyright JTWC - http://www.npmoc.navy.mil/jtwc.htm.

END REPORT


Maintained by Carl Smith.
carls@ace-net.com.au

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