Tropical weather analysis - February 26, 2013
Rusty
Tropical Cyclone Rusty is closing in on the northwest coast of Australia. As of the latest JTWC advisory, the following information was available on the storm:
Wind: 110 mph, with higher gusts
Location: 19.3°S 119.1°E
Movement: Stationary
Category: 2 (Saffir-Simpson Hurricane Scale)
And the Australian Bureau of Meteorology had to this say:
Sustained wind: 90 kt (10-minute average)
Wind gusts: 125 kt (3-second average)
Movement: Southeast at 1 mph (2 km/h)
Pressure: 945 mb
Category: 4 (Australian scale)
The cloud pattern associated with Rusty is improving as the cyclone approaches the coast, with the last few visible satellite images showing the eye becoming more distinct, although it is still a little ragged. Doppler radar from Port Hedland shows little change to the convective structure or the relative definition of the eye. The radar data indicates that the eyewall is fragmented and poorly-defined to the east.
Figure 1. Latest infrared satellite image of Tropical Cyclone Rusty. Image credit: NOAA's Satellite Services Division (SSD).
While the synoptic steering encompassing Rusty is still ill-defined, there are some signals that the mid- to upper-level flow is beginning to strengthen as a strong ridge over central Australia deepens. The global models show Rusty moving inland in later today (Australian local time), probably around 10:00 PM local time, which be roughly nine hours from now. Given current motion trends finally showing some solid movement, this seems a little slow. I'd say closer to 6 or 7:00 PM local time. It should be noted that the eye is likely to come ashore very Pardoo, and thus they are most likely to the strongest winds and heaviest rains.
Environmental conditions remain conducive to intensification in the hours remaining prior to landfall, but most likely the cyclone will remain at about the same intensity, but there could of course be fluctuations in either direction. Objective SST analyses in this region indicate that Rusty has cooled the waters underneath it by about a degree or two (C) over the last couple of days, but since these waters are deep, this is not expected to be a critical factor toward future intensity. One possible factor that could weaken Rusty a little, especially given the storm's large size and thus inherent capacity to entrain it, is the presence of dry continental air to the west, which had eroded the convection in the western portion of the cyclone circulation earlier; this dry air showed up nicely on the University of Wisconsin CIMSS MIMIC-Total Precipitable Water (TPW) product.
In any event, Rusty is running out of time to strengthen or weaken appreciably, and interests in the warning area should carefully monitor the progress of this tropical cyclone. Damage will be lessened relative to what could have occurred had the storm struck Port Hedland directly.
Rusty is expected to produce significant storm surges near and to the east of where the center makes landfall, accompanied by large and dangerous waves. Areas west of the center will see mostly offshore flow, since tropical cyclones rotate clockwise in the Southern Hemisphere, which is opposite to the Northern Hemisphere.
Heavy rainfall and associated flash flooding is also anticipated, and given the slow movement and large size of the storm circulation, rainfall amounts could be quite prodigious, on the order of 8 to 12 inches, with local amounts of 20 up to inches, especially in areas of higher terrain farther south along the track of the center after it moves inland.
Port Hedland recently reported a sustained wind of 40 mph. Although they will escape the dangerous storm surge that will be experienced in areas farther east, they are on the most dangerous side of the circulation where convection is deepest. Thus, wind gusts to hurricane force, probably up to about 80 mph, will be possible, and residents there should take Rusty extremely seriously. Rainfall will also be a serious concern.
5-day intensity forecast
INITIAL 02/26 0300Z 95 KT 110 MPH
12 hour 02/26 1200Z 95 KT 110 MPH...AT THE COAST
24 hour 02/27 0000Z 80 KT 90 MPH...INLAND
36 hour 02/27 1200Z 60 KT 70 MPH...INLAND
48 hour 02/28 0000Z 35 KT 40 MPH...INLAND
72 hour 03/01 0000Z 20 KT 25 MPH...POST-TROPICAL/REMNANT LOW
96 hour 03/02 0000Z...DISSIPATED
Storm information (Bureau of Meteorology)
IDW24100
Australian Government Bureau of Meteorology
Western Australia
Tropical Cyclone Warning Centre
Media: Transmitters serving the area between Wallal and Whim Creek are
requested to USE the Standard Emergency Warning Signal before broadcasting the
following warning.
TOP PRIORITY FOR IMMEDIATE BROADCAST
TROPICAL CYCLONE ADVICE NUMBER 32
Issued at 11:54 am WST on Wednesday 27 February 2013
A Cyclone WARNING is current for coastal areas from Bidyadanga to Dampier
including Port Hedland, Karratha and Dampier, and adjacent inland areas of the
Pilbara, including Marble Bar, Nullagine, Millstream, Tom Price, Telfer and
Newman.
A Cyclone WATCH is current for remaining central and eastern areas of the
Pilbara including Paraburdoo, Three Rivers and adjacent parts of the Gascoyne
district and the Interior.
At 11:00 am WST Severe Tropical Cyclone Rusty, Category 4 was estimated to be
125 kilometres northeast of Port Hedland and
190 kilometres north of Marble Bar and is moving southeast at 5 kilometres per
hour towards the coast.
Severe Tropical Cyclone Rusty has started to take a southeasterly track over
the last few hours. During the afternoon it is expected to take a more
southerly track as it moves towards the Pilbara coast.
Gales are occuring on the coast between Sandfire Roadhouse and Whim Creek and
will extend inland towards Marble Bar during today, and may reach Nullagine
overnight.
DESTRUCTIVE winds with gusts in excess of 125 kilometres per hour are occuring
along the coast in the vicinity of De Grey and Pardoo, and could reach Marble
Bar overnight.
VERY DESTRUCTIVE winds with gusts in excess of 165 kilometres per hour are
likely in the vicinity of De Grey and Pardoo during the afternoon and evening
as Severe Tropical Cyclone Rusty approaches the coast.
Widespread very heavy rainfall today and on Thursday is likely to lead to MAJOR
FLOODING in the De Grey catchment. Significant flooding is also possible in the
Fortescue catchment and in Pilbara coastal streams.
People on the coast between Wallal and De Grey are warned of the potential for
a VERY DANGEROUS STORM TIDE as the system approaches the coast. Tides are
likely to rise significantly above the normal high tide mark with DAMAGING
WAVES and VERY DANGEROUS COASTAL INUNDATION.
DFES State Emergency Service (SES) advises of the following community alerts:
RED ALERT: People in or near communities between Pardoo and Whim Creek,
including Port Hedland and South Hedland should remain in shelter.
YELLOW ALERT: People in communities between Wallal and Pardoo, extending inland
to Marble Bar and Nullagine need to take action and get ready to shelter from a
cyclone.
BLUE ALERT: People in communities between Bidyadanga and Wallal and between
Whim Creek and Dampier, including Karratha and extending to inland areas
including Millstream, need to prepare for cyclonic weather and organise an
emergency kit including first aid kit, torch, portable radio, spare batteries,
food and water.
ALL CLEAR: People in communities from Mardie to Dampier are advised that the
cyclone danger has passed.
Details of Severe Tropical Cyclone Rusty at 11:00 am WST:
.Centre located near...... 19.5 degrees South 119.4 degrees East
.Location accuracy........ within 30 kilometres
.Recent movement.......... towards the southeast at 5 kilometres per hour
.Wind gusts near centre... 230 kilometres per hour and weakening
.Severity category........ 4
.Central pressure......... 945 hectoPascals
The next advice will be issued by 3:00 pm WST Wednesday 27 February.
Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210
A map showing the track of the cyclone is available at:
http://www.bom.gov.au/cyclone
Watches and warnings
A Cyclone WARNING is current for coastal areas from Bidyadanga to Dampier
including Port Hedland, Karratha and Dampier, and adjacent inland areas of the
Pilbara, including Marble Bar, Nullagine, Millstream, Tom Price, Telfer and
Newman.
A Cyclone WATCH is current for remaining central and eastern areas of the
Pilbara including Paraburdoo, Three Rivers and adjacent parts of the Gascoyne
district and the Interior.
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