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Severe Tropical Cyclone Gillian


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Posted
  • Location: The Netherlands
  • Location: The Netherlands

A new tropical low has formed in the Australian basin, just to the north of the Gulf of Carpentaria. The system currently cosists of flaring, though vigorous convection. This can be seen in the visible satellite loop below:

 

Posted Image

 

For the time being, little to nog cyclonic turning can yet be observed, but this could change in the near term. Currently, most of the convection is being transported southward due to some northerly shear (as analyzed by CIMSS).

 

The cyclone is forecast to develop into a category 2 cyclone (winds between 55 and 71 knots), and make landfall in the northern tip of Queensland. The graphical forecast of the cyclone by the BOM can be seen below:

 

Posted Image

 

Sources:

http://www.bom.gov.au/products/IDQ65004.shtml

http://en.wikipedia.org/wiki/2013%E2%80%9314_Australian_region_cyclone_season#Tropical_Low_14U

http://www.ssd.noaa.gov/PS/TROP/floaters/98P/98P_floater.html

http://en.wikipedia.org/wiki/Tropical_cyclone_scales

http://tropic.ssec.wisc.edu/#

 

Edited by Somerset Squall
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Posted
  • Location: The Netherlands
  • Location: The Netherlands

14U has been upgraded to tropical storm Gillian, by the JTWC as well as by the Bureau of Meteorology. The cyclone is currently suffering from (north)easterly shear, as can be seen in the visible loop posted above. Although a LLCC has finally developed, it is exposed to the west of the main area of convection. From the BOM technical bulletin:

 

 

 

The LLCC is fully exposed with a small area of deep convection west of the system centre maintaining against NE vertical wind shear.

 

Of note is that there is a big discrepancy in the forecast tracks from the JTWC and BOM. The BOM expects landfall on the western Cape, while the JTWC forecasts the system to recurve to the southwest, and miss the western Cape completely. The tracks can be seen below:

 

BOM:

Posted Image

 

JTWC:

Posted Image

 

It will be interesting to see which of the forecast tracks is closest to the mark.

 

Sources:

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDQ20068.txt

http://www.usno.navy.mil/JTWC/

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Indeed Vorticity, I think there will be a lot of changes to the track of Gillian over the next few days. This is to be expected given the weak steering environment. JTWC are going with the idea of a ridge building to the south deflecting Gillian southwest. It's worth noting that JTWC also mention BOM's scenario of a Cape York Peninsula landfall as a possibility, though they do not explicity forecast it currently. The track will govern how strong Gillian will get aswell to a degree, especially as the shear is lower in the southwestern Gulf Of Carpentaria.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

BOM latest track shifted west towards the JTWC forecast, also forecasts significantly higher intensities as Gillian moves into lower shear. If this forecast materialises, Mornington Island and nearby coastal communities will be impacted by a cat 3 severe tropical cyclone on the Australian scale.

 

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Posted
  • Location: Hobart, Tasmania
  • Location: Hobart, Tasmania

80% of the vast state of Queensland is currently drought declared ( record area ), cyclones under these conditions are usually enthusiastically welcome. It appears however the cyclone tracks will not be conducive to inland rainfall.

 

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Posted
  • Location: The Netherlands
  • Location: The Netherlands

80% of the vast state of Queensland is currently drought declared ( record area ), cyclones under these conditions are usually enthusiastically welcome. It appears however the cyclone tracks will not be conducive to inland rainfall.

 

The track forecast of the Bureau of Meteorology has shifted westward somewhat, as Tropicbreeze stated. This will improve chances of some inland rainfall, though not really in Queensland itself. On the contrary, the current track of Gillian has made a significant eastward jog, as can be seen in the visible loop below:

 

Posted Image

 

Note that the LLCC of Gillian has clearly been moving eastward when there was no convection overhead. None of the agencies (JTWC/BOM) predicted this eastward motion reasonably (though BOM forecasted a motion in the northern part of Queensland in their first advisory package).

 

With this unexpected motion, the track forecasts have once again made a significant shift eastward (short term) to account for the initial position. This, combined with the westward shift in the extended time period, really confirms your statement of jumps in the forecast track, Sommerset squall Posted Image

 

Meanwhile, Gillian is still struggeling with the easterly shear, as convective bursts develop and immediately get sheared westward. Both the JTWC and BOM have lowered their intensity forecasts, with the BOM no longer expecting a category 3 cyclone (winds above 72 kt) to develop.(BOM-hurricane scale)

 

Finally, a nice image of MIMIC-TPW (total precipitable water content), showing Gillan in the Gulf of Carpentaria, newly developed cyclone Hadi (13U) to the east of Australia and also newly-developed cyclone Eighteen (as from JTWC) to the west of Fiji.

 

Posted Image

 

Sources:

http://www.usno.navy.mil/JTWC/

http://tropic.ssec.wisc.edu/real-time/mimic-tpw/ausf/main.html

http://www.bom.gov.au/cyclone/

http://www.nhc.noaa.gov/

http://en.wikipedia.org/wiki/Tropical_cyclone_scales

Edited by Vorticity0123
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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

JTWC have declared that Gillian has made a landfall on the west coast of the Cape York Peninsula, wheras BOM have Gillian analysed just off shore. That's quite clearly telling us that Gillian is a mess and therefore it's LLCC is difficult to locate exactly. Regardless of where the centre of the cyclone is, it is feeling the affects of land interaction and persistantly strong easterly shear. Both of these negative factors should reduce somewhat as Gillian finally turns southwest over the next couple days, which should allow some strengthening past it's current 35kt intensity.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Gillian certainly doesn't want to get away from the west coast of the Cape York Peninsula! And what a mess it is as a result! Hardly surprising BOM are no longer regarding this system as a tropical cyclone. If it wants to re-strengthen, it needs to swing west, and fast.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Gillian remains over land, and JTWC have issued their last advisory too. JTWC assess the chances of redevelopment in the next 24hrs as low, as the environment remains hostile in this time. Ex-Gillian may have a brief window of opportunity to redevelop as it eventually moves back out into the Gulf Of Carpentaria, before conditions worsen again, as Tropicbreeze has indicated, as shear and dry air overwhelm the system.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

GFS has Gillian reforming in the Gulf later in the week and crossing the coast near Gove on Sunday with 80 kt winds. Then moving overland to Darwin before crossing into the Timor Sea and reintensifying. I don't think the other models are favouring it that much.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

BOM is now giving Gillian the same track as Monica. There was also dry air for Monica to contend with but it still peaked as a high end cat 5 north of Gove. The SSTs there are accommodating enough for that, but not shear.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Yeah, very interesting track to say the least. Gillian doing a lap around the coastline of the Gulf Of Carpentaria it seems. It'll be interesting to see if it makes it over the Top End and over into the South Indian Ocean to impact NW Australia.

 

Posted Image

 

Ex-Gillian, as you can see, has moved out into the Gulf Of Carpentaria. The LLC is weak and the convection is not very deep or organised. But now the remnant low is away from the Cape York Peninsula, it has a greater chance of redevelopment.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

Not unusual for TC's to weave extremely erratic tracks in this area. Steer is often not very strong.Easy to see where ex-Gillian is on the Mornington radar. Expected to begin moving to the northwest soon. Cyclone warning has been extended to Maningrida.post-22057-0-81451600-1394700427_thumb.jBOM still expects it to reintensify when it reaches the Timor Sea. They have it moving away from the coast. But by then steer might bring it back on Darwin or the Kimberley Coast.On a side note, a storm has hit here. Max rainfall rate was 235 mm per hour for a short while. Got over 62 mm in the past half hour, and it's still raining fairly heavily. House is shaking from the thunder (maybe it's scared, LOL). 

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

IDD20021TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - NORTHERN REGIONIssued by DARWIN TROPICAL CYCLONE WARNING CENTREat: 0156 UTC 14/03/2014Name: Ex-Tropical Cyclone GillianIdentifier: 14UData At: 0000 UTCLatitude: 14.0SLongitude: 139.3ELocation Accuracy: within 45 nm [85 km]Movement Towards: slow movingSpeed of Movement: slow movingMaximum 10-Minute Wind: 30 knots [55 km/h]Maximum 3-Second Wind Gust: 45 knots [85 km/h]Central Pressure: 1002 hPaRadius of 34-knot winds NE quadrant:  Radius of 34-knot winds SE quadrant:  Radius of 34-knot winds SW quadrant:  Radius of 34-knot winds NW quadrant:  Radius of 48-knot winds NE quadrant:  Radius of 48-knot winds SE quadrant:  Radius of 48-knot winds SW quadrant:  Radius of 48-knot winds NW quadrant:  Radius of 64-knot winds:  Radius of Maximum Winds:  Dvorak Intensity Code: T2.5/2.5/D1.0/24HRSPressure of outermost isobar: 1009 hPaRadius of outermost closed isobar: 90 nm [165 km]FORECAST DATADate/Time   : Location   : Loc. Accuracy: Max Wind : Central Pressure[uTC]   :       degrees : nm  [km]: knots[km/h]: hPa+06:  14/0600: 13.7S 139.1E: 040 [080]:  030  [055]: 1005+12:  14/1200: 13.5S 138.8E: 055 [100]:  035  [065]: 1001+18:  14/1800: 13.2S 138.4E: 065 [125]:  035  [065]: 1001+24:  15/0000: 12.9S 138.0E: 080 [145]:  040  [075]: 1000+36:  15/1200: 12.3S 137.0E: 100 [185]:  040  [075]: 1000+48:  16/0000: 11.9S 136.0E: 120 [220]:  030  [050]: 1004+60:  16/1200: 11.6S 134.7E: 140 [255]:  025  [045]: 1005+72:  17/0000: 11.3S 132.8E: 155 [290]:  025  [045]: 1006+96:  18/0000: 11.1S 127.6E: 200 [370]:  025  [045]: 1007+120: 19/0000: 11.1S 121.1E: 290 [535]:  035  [065]:  999REMARKS:The system has shown significant improvement in organisation over the last 6 hours, with convection increasing and consolidating in the central Gulf of Carpentaria. Position is based on 2330UTC satellite image, and the Mornington Island and Gove radars. Curved band 0.6 wrap yields DT=3.0, with better central features. CDO pattern with the 85nm diameter also gives of 3.0 and if we include a weak banding of 0.5, it gives DT=3.5. MET=2.5, PAT gives 2.5. FT=2.5 based on MET and PAT.The low is located near the upper level ridge with weak shear [about 10 knots] over the system. The low level centre has been slowly moving NE over the last 6 hours in response to a mid/upper trough moving just south of the system. Beyond the short term, a building mid level ridge over Central Australia  will steer the system towards the northwest.The system is expected to continue intensifying in the short term before increasing S/SE wind shear and mid level dry air entrainment due to the building ridge to the south and west arrests development. Beyond 24 hours, land interaction is expected to weaken the system below tropical cyclone strength.Once the system moves into the Timor Sea it will encounter more favourable conditions and may begin to slowly intensify.Most models are in agreement with the cyclone tracking along the north coast of the Top End, NT. However there is significant variation in model intensity guidance.Copyright Commonwealth of Australia==The next bulletin for this system will be issued by: 14/0730 UTC by Darwin TCWC. 

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Gillian is back from the grave and has become a tropical cyclone again, with winds of 35kts according to BOM. Gillian is drifting slowly northwards in the Gulf Of Carpentaria currently, but should veer northwestwards soon. Convection is blossoming over the LLCC, and Gillian shoukd strengthen a little before interacting with the Northern Territory coast.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

IDD20250Australian Government Bureau of MeteorologyNorthern TerritoryTropical Cyclone Warning CentreMedia: The Standard Emergency Warning Signal should NOT be used with this warning.TOP PRIORITY FOR IMMEDIATE BROADCASTTROPICAL CYCLONE WARNINGTROPICAL CYCLONE ADVICE NUMBER 41  Issued at 4:43 pm CST on Friday 14 March 2014A Cyclone WARNING continues for coastal and island communities from Elcho Island to Numbulwar, including Alyangula and NhulunbuyA Cyclone WATCH is now current for coastal areas from Croker Island to Elcho IslandAt 3:30 pm CST Tropical Cyclone Gillian was estimated to be325 kilometres east of Groote Eylandt and325 kilometres east southeast of Nhulunbuymoving north northeast at 10 kilometres per hourTROPICAL CYCLONE GILLIAN is moving slowly north over the Gulf of Carpentaria. Tropical Cyclone Gillian is expected to turn northwest overnight and move towards the northeast Arnhem district. It is expected to cross the coast near Nhulunbuy during Saturday night or early Sunday morning. It is then expected to continue moving west near the north coast of the Top End.GALES with gusts to 110 kilometres per hour are expected to develop between Numbulwar and Nhulunbuy, including Alyangula, during Saturday, extending to Elcho Island later on Saturday.GALES may extend further west to Maningrida Saturday night or on Sunday, then Croker Island on Sunday night.Tides will be HIGHER THAN NORMAL between Numbulwar and Nhulunbuy. Large waves may produce MINOR FLOODING of low-lying coastal areas.HEAVY RAIN may lead to flash flooding in coastal areas of northeast Arnhem Land on Saturday, extending west across the north coast on Sunday.The Territory Controller advises residents from Elcho Island to Numbulwar that now is the time to make final preparations to your home shelter.The Territory Controller advises Northern Territory communities under Watch that now is the time to put together your emergency kit, clear your yards and balconies, and commence home shelter preparations.Details of Tropical Cyclone Gillian at 3:30 pm CST:.Centre located near...... 13.5 degrees South 139.5 degrees East.Location accuracy........ within 85 kilometres.Recent movement.......... towards the north northeast at 10 kilometres per hour.Wind gusts near centre... 95 kilometres per hour.Severity category........ 1.Central pressure......... 997 hectoPascalsPlease ensure that neighbours have heard and understood this message, particularly new arrivals or those who may not fully understand English.The next advice will be issued by 8:00 pm CST Friday 14 March.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Gillian is now moving northeast, and is almost at the location where she formed a week ago! The unexpected northeasterly motion means that when Gillian does turn northwest it may move north of the NT coast now rather than dragging across it, which means that Gillian should remain a tropical cyclone over the next several days.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

It's started turning NW and is expected to track clear of the NT coast. Dry air and VWS increase along that track which is now identical to the track taken by TC Monica. By Tuesday it's expected to be near the Tiwi Islands/Darwin. GFS has it affecting Darwin on Monday, then continuing across the Timor Sea and out into the Indian Ocean.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Gillian has been declared a remnant low for the second time this morning. Shear has negatively impacted the system overnight, and caused BOM to downgrade the system again. JTWC have just reissued their TCFA, which they have had out for about 30hrs on the system. Ex-Gillian's convection is quite vigorous, but the LLC is elongated due to the shear. Shear is expected to remain at at least moderate levels as the system tracks west towards the Top End, so significant intensification appears unlikely. However, it would only take a small increase in organisation for Ex-Gillian to become a TC for the third time, albeit likely only a weak one unless shear eases.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

It's only a small system so it can change rapidly. BOM has it remaining a tropical low for the next 3 days. Under current expectations it's more likely to affect Timor than the Australian mainland.

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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

Ex-Gillian is still moving slowly north of the Top End coast. Convection has increased but shear is still fairly high. The LLCC is displaced to the east south east of the mid level centre.

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