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Aussie (& S-Hemisphere) Cyclone Action 2011-2012


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Lua's been upgraded to a Severe Tropical Cyclone (Cat 3 AUS), with 10-min winds of 65 kt. A Cyclone Warning is up along the coast for a wide area that includes Karratha, Port Hedland, and Broome. The system is accelerating-- after really dawdling for several days-- and landfall is expected near Pardoo in ~24 hr.

FYI, Pardoo is not a town, but simply the location of an iron-ore mine and cattle station. This part of the Australian coast is like Kenedy County, TX-- rather desolate. However, Port Hedland needs to remain vigilant, as a slight deviation to the W of the forecast track will bring the cyclone's core over the town:

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BOM still going with a Cat 4 landfall near Pardoo. Extremely cold cloud tops continue to fire near the ragged eye, with better conditions still awaiting near the coast.

Interesting-- they actually bumped it back up again. The last two advices did not bring it up to Cat 4-- so I guess their previous confidence is renewed.

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Last night (US time) before bed, vis imagery suggested it was forming an eye, and now IR imagery seems to confirm.

May finally be a go for intensification at a more pronounced rate, if I had to guess.

UW - CIMSS

ADVANCED DVORAK TECHNIQUE

ADT-Version 8.1.3

Tropical Cyclone Intensity Algorithm

----- Current Analysis -----

Date : 16 MAR 2012 Time : 113000 UTC

Lat : 16:55:24 S Lon : 117:17:22 E

CI# /Pressure/ Vmax 4.3 / 969.0mb/ 72.2kt

Final T# Adj T# Raw T#

4.3 4.3 3.8

Center Temp : -86.8C Cloud Region Temp : -84.0C

Scene Type : UNIFORM CDO CLOUD REGION w/ MW EYE

post-138-0-20137200-1331901436.jpg

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Last night (US time) before bed, vis imagery suggested it was forming an eye, and now IR imagery seems to confirm.

May finally be a go for intensification at a more pronounced rate, if I had to guess.

Yeah, it's definitely looking better now.

FYI on the chase team.... they have negotiated to stay in a mining camp about 1-2km off the coast at Pardoo.

That is in a pretty direct line of the cross.

WTG boys...

Oh, that's awesome! :thumbsup: Great news. Cool. Let's how the cyclone stays on course so they get the inner core.

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I notice the latest BoM forecast has nudged a tad E and is now halfway between Pardoo and Wallal. The cyclone's core looks quite small in MW imagery, so I hope the Oz chaser dudes are able to adjust their position, if necessary. I know there's very little in this part the Pilbara-- just a long highway-- so locations will be a challenge.

The imagery is still not amazing-- Lua has never had a classic, round, symmetric look-- but you can see a fairly well-defined core. The current BoM intensity is 75 kt (10-min), current JTWC intensity is 75 kt (1-min):

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BoM has just re ramped her back up to Cat 4... the new cross point is just north of the team ( i think they are pretty locked in where they are... which may be a shame as it seems the greatest output will be to the north)

The BoM brought the forecast back up to Cat 4 a couple of advices earlier, actually (see above).

I think the issue is that the cyclone's core might past E of them. The forecast track would have Pardoo outside of the core to the W-- so hopefully they can get on that highway and adjust as needed. Maybe they can find some shrubs or trees along the highway to nuzzle up against. It looks to be a daytime landfall, which will help.

These guys have worked so hard and come so far to chase this baby-- so I hope they get in that core.

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Rowley Shoals-- that station near the eye on the radar-- reported 73 kt from the N and 939 mb at 1 am WST. That would suggest te center passed just to the W. Pressure's rising again and the wind has shifted, so it seems the center might have passed the station. It's only reporting once an hour now, so we might have missed the best of it.

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The BoM has upgraded Lua to Cat 4, which means winds are at least 90 kt (10-min). Highest wind reported from Rowley Shoals was 75 kt from the WNW, about an hour after the pressure bottomed out in the high 930s.

The pressure and wind traces from that station suggest the center passed very close by around 2 am. I say this because the winds dropped to 46 kt at that time (preceded by a max of 73 kt at 1 am and followed by the later max of 75 kt at 3 am).

JTWC has it at 90 kt (1-min)-- a little more conservative.

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Lua is approaching the coast and continues to intensify. The BoM now has it up to 932 mb/95 kt (10-min). The MW imagery looks pretty good. The eye is clearly visible on Port Hedland radar.

Interestingly, it looks like my chaser buddies in Pardoo might be very well-situated after all! The motion has recently trended from SE to more SSE-- and I think they might even get in the eye. Not only that-- it's an afternoon landfall. Awesome-- should see some good footage form those guys:

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Lua is moving inland.

The BoM's technical discussion put the landfall intensity at 932 mb/95 kt (10-min)-- which is a solid Cat 3 on our scale. The JTWC called it more conservatively, showing 95 kt (1-min)-- a strong Cat 2.

Either way, it's a solid cyclone with a good radar presentation. The Oz Cyclone Chasers reported "extremely violent wind" as the center passed to their E. I'm very much looking forward to seeing their video footage:

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Hey Worf (aka Al) be aware the chasers are fine.

Again.... what do you know about secondary eyewalls.. I think the team has captured something unique.

But I may be wrong.

Thoughts?

I suppose an eyewall replacement cycle could have been happening, but obviously Adam, as a highly paid professional, would be better able to answer the question.

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Hey Worf (aka Al) be aware the chasers are fine.

Again.... what do you know about secondary eyewalls.. I think the team has captured something unique.

But I may be wrong.

Thoughts?

Probably formative stages of a concentric eyewall. It's rather common in strong cyclones, there are many cases where a very distinctive moat shows in radar/MW imagery, where wind/rain conditions are in a relative minimum close to the eyewall whereas a bit farther out you can experience a secondary maxima. This secondary maxima enhanced convection created a subsidence area around it, which is what was probably experienced.

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Secondary or concentric eyewalls are fairly common. Hurricane Charley displayed a very clear one-- with a defined moat separating primary and seconday eyewalls-- when it hit Florida, and chaser footage showed a period of lighter winds and brighter skies in between. But even lesser storms can have them-- like Cyclone Heidi, earlier this year: Port Hedland was inside the outer eyewall but missed the inner one.

Can't wait to see the footage from the guys!

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The complete operational Lua tracks from both the BoM and JTWC.

Track-wise, the cyclone was quite behaved-- took pretty-much the path that was forecast by both the BoM and the JTWC, although the BoM was a bit closer. (The models were in good agreement prior to landfall, so this is no surprise.) Intensity-wise, the BoM's bullish forecast turned out to be more accurate than the JTWC's more bearish one.

Overall, the BoM did very well with this one.

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Let's not talk about anything that originates in the NT... but, then again, buckets of rain and a rare tornado for Oz... 25 five house decapitated in Townsville ( while the chasers are away the weather will play).

HOWEVER... the Coral Sea is looking...... very................. tasty

Take a look.

Could you be more specific? I'm missing something in the Coral Sea...

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