The graphics and statistical information on this page fill gradually as they become available, with some not available until the next day. The page is updated every 30 minutes at about 20 and 50 minutes past the hour.

For weather news as it breaks that is tagged and organised, use the links on the Weather and Climate Media Reports page.

Sunday 26 March 2017

 Tropical Cyclone Debbie intensifies to Category 2 overnight
Updated 26/3/17 20.00EDT: See second story below
********************************************

TC Debbie intensified to a Category 2 system on Saturday evening and is expected to intensify further to Category 3 by late this afternoon. The cyclone, which is now packing winds averaging 100km/h and gusting to 140km/h near the centre, continues to be slow moving, but is expected to swing to the WSW and pick up speed later this morning. Landfall is currently expected to be between Townsville and Proserpine on Tuesday morning, or at earliest overnight Monday, at Category 4 intensity.

Residents on the coast and islands between Ayr and Mackay should see gales develop this afternoon or evening, extending south to St Lawrence by this evening and north to Cairns and inland to Charters Towers during tomorrow. Destructive winds with gusts over 125km/h are expected to develop along the coast and islands between Lucinda and Mackay tomorrow afternoon or evening.

The latest Tropical Cyclone Advice issued at 04.41EST also warns that "abnormally high tides are expected to occur between at least Lucinda and Mackay as the cyclone approaches the coast. Large waves may also develop along the beachfront." With high wind and seas expected, it also warns that "People living in areas likely to be affected by this flooding should take measures to protect their property as much as possible and be prepared to follow instructions regarding evacuation of the area if advised to do so by the authorities."

More general flash flooding is expected to be a problem along the northern and central QLD coasts and adjacent inland between Sunday and Tuesday, with broadscale major river flooding a threat. A Flood Watch is current for coastal rivers from Cairns to Gladstone and inland to the eastern Gulf rivers.

TC Debbie's central pressure had dropped to 984hPa at 04.00EST and the system continues to show improved signs of development, although a central eye is still not clear on the first visible satellite images after sunrise. The slow movement is a result of weak steering at present, but a middle atmosphere ridge building to the south of the cyclone as forecast will steer the cyclone to the WSW right through until landfall.

The environment surrounding Debbie remains excellently suited to further development right up to landfall, with some guidance suggesting a 30% chance of rapid intensification during today or early tomorrow.

To keep fully up to date, use the TCWC Current Tropical Cyclones page to access all available warnings, track maps, technical information and backgrounder advice in the one place.

 TC Debbie to intensify to Category 3 tonight as it approaches coast

Tropical Cyclone Debbie has steadily picked up speed and strength as it moved towards the QLD coast today. At 16.00EST it was moving at 8km/h towards the SW, and was expected to swing to a WSW direction and increase to a Category 3 intensity overnight. Estimated winds near the centre at that time were a 10-minute average of 110km/h with gusts to 155km/h. The cyclone was located about 330km ENE of Bowen and 440km ENE of Townsville.

Forecasters at the BoM Tropical Cyclone Warning Centre in Brisbane see no change in the broad pattern that will steer Debbie on a WSW course towards the coast. With sea surface temperatures of 29 to 30° and excellent, undisturbed upper-level outflow all around the cyclone to disperse its mighty updrafts, conditions remain favourable for its development right up to landfall when it is expected to be at Category 4 intensity. In its late afternoon Technical Bulletin, the TCWC notes that two sets of guidance it has recently received "suggest a period of rapid intensification is possible in the next 24 hours. Given this evidence, the intensity may be higher than forecast approaching landfall."

This evening's warning expects landfall to be somewhere between Rollingstone, a small settlement 50km NW of Townsville, and Proserpine, 220km SE of Townsville, meaning that a landfall close to Townsville is still a possibility. Gales are expected to develop on the coast and islands between Ayr and Mackay this evening, and could extend to remaining areas between Lucinda and St Lawrence during Monday, then north to Innisfail and inland to Charters Towers and Mount Coolon on Monday evening or Tuesday morning.

Destructive winds with gusts over 125km/h are expected to develop about the exposed coast and islands between Ayr and Mackay during Monday morning, extending north to Lucinda by the evening. Winds in the very destructive core of the cyclone are expected to gust up to 260km/h. Because of the large size of the cyclone, destructive winds will extend well out from the central core. Debbie is also expected to maintain cyclone strength, with damaging to destructive winds, as it tracks inland towards Charters Towers.

An increasing concern reflected in the TCWC warnings is that of abnormally high tides and damage from high seas sweeping inshore. The Barometric pressure at 04.00EST Tuesday, around the time Debbie is expected to be close to crossing the coast, is 942hPa which, combined with hurricane force winds, would create major storm surge damage. Low air pressure means there is less weight of air above the sea allowing it to bulge upwards. The high winds push water towards the shore piling them higher on the shoreline and in estuaries, causing flooding and wave damage well above the normal level reached by waves. This evening's warning is more detailed than previous warnings about this.

It says "Abnormally high tides are expected to occur south of Proserpine on the high tides on Monday. On Tuesday, residents between Rollingstone and Mackay are specifically warned of the dangerous storm tide as the cyclone crosses the coast. The sea is likely to rise steadily up to a level well above the normal tide, with damaging waves and flooding of some low-lying areas close to the shoreline as the cyclone approaches the coast on Tuesday. Large waves may also develop along the beachfront. People living in areas likely to be affected by this flooding should take measures to protect their property as much as possible and be prepared to follow instructions regarding evacuation of the area if advised to do so by the authorities."

The warning, and associated Flood Watch, have ramped up the level of flooding expected. "Areas of heavy rain with the potential to cause severe flash flooding are expected to develop about parts of the northern and central Queensland coast and adjacent inland areas late on Sunday and continue through Monday and Tuesday," it says. "Widespread daily rainfall totals of 200 mm, with isolated falls of 400 mm, [are] also likely to lead to major river flooding over a broad area next week, and a Flood Watch is current for coastal catchments between Cardwell and Gladstone, extending inland to the eastern Gulf River catchments."

 North QLD gets cyclone-ready: on the ground

As North Queenslanders prepare for a major cyclone, comparisons are being made with TC Yasi six years ago which caused widespread and major damage to the region, some of which took years to overcome. Storm surges were a major factor in Yasi's $800 million damage footprint and, while Debbie may be less powerful than Yasi on landfall if it arrives as a Category 4 cyclone, it will be of a similar size. With memories of Yasi fresh in their minds, locals are taking the warnings very seriously.

Evacuations began today at a number of coastal communities susceptible to storm surges between Townsville and Proserpine and on the Whitsunday Islands [SBS]. Household preparation has been under way, especially clearing potential airborne objects. Long queues developed at some local tips, prompting one Tweeter to tweet "Our yard has not been so neat and tidy since #cycloneyasi". Local supermarket shelves are virtually empty of basic products, service stations have been "going crazy" selling petrol and there is widespread sandbagging to protect flood-vulnerable property.

A thousand emergency services personnel as well as an Australian Defence Force taskforce have already been positioned between Townsville and Mackay to prepare for a potential natural disaster. Most flights have been cancelled for Townsville and other airports in the region for at least Monday and Tuesday [SBS]. Townsville Hospital has cancelled elective surgery to prepare for disaster emergencies while schools between Ayr and Proserpine have been closed from tomorrow and others may follow. James Cook University's campuses from Cairns to Mackay will be closed. [SBS, ABC, Guardian]