Tropical Cyclone Helen

[Cookie]

Storm Alert issued at 3 Jan, 2008 18:00 GMT

Tropical Storm 10S is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

Australia

probability for TS is 90% currently

Yellow Alert City(s) and Town(s)

Port Keats (14.2 S, 129.6 E)

probability for TS is 70% within 12 hours

Kalumburu (14.2 S, 126.6 E)

probability for TS is 65% currently

[Somerset Squall]

Thanks for the update Cookie.

Tropical Cyclone 10S has just been upgraded to Tropical Cyclone Helen. The cyclone has taken advantage of low to moderate shear and high sea temps to strengthen. However, it's time over water is expected to be limited as it's expected to track eastwards and make landfall in Darwin where it may cause destructive winds and heavy rains.

The BOM shows this in their advisory for Helen: http://www.bom.gov.au/products/IDD65011.shtml

Take note of the track image: Helen or her remnants are expected to re-emerge in the Gulf Of Carpentaria in about 48hrs time. Waters are very warm in the GOC and the JTWC in particular are expecting Helen to re-strengthen after it's treck over land. An interesting storm this one, it's been a developing low inland over Darwin for days- to emerge in the Joseph Bonaparte Gulf and develop into a cyclone then head back eastwards over Darwin again! Bound to cause problems as it's expected to make landfall at cat 2 strength on the Australian scale and who knows what it will do when it reaches the GOC! One to watch.

Satellite image of Helen: (the tight swirl roughly centre-top of image)

Taken from: http://cimss.ssec.wisc.edu/tropic/real-tim...ges/images.html

Edited January 4, 2008 by Somerset Squall

[Somerset Squall]

Helen has continued to strengthen and is now a cat 2 on the Australian scale. It has another 12 hours before landfall in which it could strengthen some more as upper level winds are favourable. It is still expected to survive it's treck over land and re-intensify over the Gulf Of Carpentaria. It's anyone's guess at the moment how strong it will become there.

[Cookie]

cool thanks for the update

[Cookie]

Storm Alert issued at 4 Jan, 2008 6:00 GMT

Tropical Storm HELEN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

Australia

probability for TS is 80% currently

Yellow Alert City(s) and Town(s)

Darwin (12.4 S, 130.8 E)

probability for TS is 80% within 12 hours

Batchelor (13.0 S, 131.0 E)

probability for TS is 80% within 12 hours

Port Keats (14.2 S, 129.6 E)

probability for TS is 65% within 12 hours

[Somerset Squall]

Helen making landfall:

http://www.abc.net.au/news/stories/2008/01...?section=justin

[Cookie]

Storm Alert issued at 4 Jan, 2008 18:00 GMT

Tropical Storm HELEN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

Australia

probability for TS is 100% currently

Yellow Alert City(s) and Town(s)

Batchelor (13.0 S, 131.0 E)

probability for TS is 100% currently

Darwin (12.4 S, 130.8 E)

probability for TS is 95% currently

Katherine (14.0 S, 132.5 E)

probability for TS is 85% within 12 hours

Oenpelli (12.3 S, 133.0 E)

probability for TS is 80% within 12 hours

Alyangula (13.9 S, 136.5 E)

probability for TS is 65% in about 24 hours

Numbulwar (14.5 S, 135.5 E)

probability for TS is 65% in about 24 hours

Nhulunbuy (12.2 S, 136.8 E)

probability for TS is 55% in about 24 hours

[Cookie]

Storm Alert issued at 5 Jan, 2008 6:00 GMT

Tropical Depression HELEN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

Australia

probability for TS is 85% currently

Yellow Alert City(s) and Town(s)

Alyangula (13.9 S, 136.5 E)

probability for TS is 85% within 12 hours

Numbulwar (14.5 S, 135.5 E)

probability for TS is 75% within 12 hours

Nhulunbuy (12.2 S, 136.8 E)

probability for TS is 60% in about 24 hours

Edward River (15.0 S, 141.7 E)

probability for TS is 55% in about 36 hours

Kowanyama (15.8 S, 141.8 E)

probability for TS is 55% in about 36 hours

[Somerset Squall]

Helen is now at tropical depression strength (30kts according to JTWC) but it is just emerging into the Gulf Of Carpentaria where it is likely to re-intensify significantly as waters are very warm and shear is low. Helen is expected to cross the GOC and make a second landfall on the Cape York Peninsula where it is expected to finally dissapate. At final landfall, Helen is expected to be a cat 2 on the Australian scale which is likely to cause downing of trees, minor structural damage and flooding, much like it has already done in the Darwin area.

http://www.abc.net.au/news/stories/2008/01/05/2132418.htm

Edited January 5, 2008 by Somerset Squall

[Cookie]

thanks for the update

[Cookie]

another update on this one.

Storm Alert issued at 5 Jan, 2008 18:00 GMT

Tropical Depression HELEN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

Australia

probability for TS is 85% currently

Yellow Alert City(s) and Town(s)

Alyangula (13.9 S, 136.5 E)

probability for TS is 80% currently

Edward River (15.0 S, 141.7 E)

probability for TS is 60% in about 36 hours

Kowanyama (15.8 S, 141.8 E)

probability for TS is 55% in about 36 hours

[Icer]

Image

Image 2

Looking rough down there flooding and it's been called a disaster zone done there!

Edited January 6, 2008 by Icer

[Somerset Squall]

Well, a simple trip across the Gulf Of Carpentaria is now not certain. The models are all over the place but a developing steering ridge to the south is being predicted which, after Helen gets close to the Cape York Peninsula (36hrs), may force Helen slowly back westward over the GOC once more. The JTWC and BOM differ on what they think will happen with Helen. Firstly, the JTWC:

TROPICAL CYCLONE (TC) 10S (HELEN), LOCATED APPROXIMATELY 345 NM EAST

OF DARWIN, AUSTRALIA, HAS TRACKED EASTWARD AT 17 KNOTS OVER THE PAST

06 HOURS. DVORAK SATELLITE FIXES FROM PGTW AND ADRM, RADAR IMAGERY

FROM GOVE, AUSTRALIA, AND SYNOPTIC OBSERVATIONS FROM THE AREA AFFECT-

ED BY THE STORM INDICATE THAT TC 10S HAS REEMERGED OVER WATER IN THE

NORTHWESTERN GULF OF CARPENTARIA DURING THE PAST 06 HOURS. THE WEAK-

ENED SYSTEM CONTINUES TO TRACK EASTWARD IN RESPONSE TO STRONG LOW TO

MID-LEVEL WESTERLY FLOW ASSOCIATED WITH NEAR-EQUATORIAL RIDGING TO

THE NORTH. WESTERLY TO NORTHWESTERLY STEERING FLOW IS EXPECTED TO

PERSIST THROUGH TAU 36, CARRYING THE STORM EASTWARD TOWARD THE CAPE

YORK PENINSULA. HOWEVER, FORWARD MOTION SHOULD SLOW IN THE NEAR TERM

AS THE SYSTEM BEGINS TO REORGANIZE OVER WATER AND LATER IN THE FORE-

CAST PERIOD AS A BUILDING SUBTROPICAL RIDGE TO THE SOUTH BEGINS TO

EXERT A COMPETING STEERING INFLUENCE. BY TAU 48, SUBTROPICAL RIDGING

WILL BECOME WELL-ESTABLISHED, AND IS EXPECTED TO TURN THE STORM WEST-

WARD AFTER A BRIEF PERIOD OF QUASISTATIONARY MOTION. THE EXACT STORM

TRACK DEPENDS ON HOW QUICKLY THE SUBTROPICAL STEERING RIDGE TO THE

SOUTH DEVELOPS AND BEGINS TO INFLUENCE THE STORM. IF THIS RIDGE

DEVELOPS QUICKLY, THE STORM MAY REMAIN OVER THE GULF OF CARPENTARIA,

TURNING WESTWARD BEFORE MAKING LANDFALL IN THE CAPE YORK PENINSULA.

TC 10S IS FORECASTED TO INTENSIFY SLOWLY OVER THE NEXT 24 HOURS AS

THE SYSTEM STRUGGLES TO REORGANIZE UNDER THE COMPETING INFLUENCES OF

FAVORABLE DIFFLUENCE ALOFT AND MODERATE TO HIGH OCEAN HEAT CONTENT

AND UNFAVORABLE WESTERLY VERTICAL WIND SHEAR. THE STORM MAY EXPERI-

ENCE A BRIEF PERIOD OF MORE RAPID INTENSIFICATION BEFORE MAKING

LANDFALL IN THE CAPE YORK PENINSULA AS IT PASSES OVER AN AREA OF

HIGH OCEAN HEAT CONTENT OBSERVED NEAR THE COAST. MAXIMUM SIGNIFICANT

WAVE HEIGHT AT 051800Z IS 10 FEET. NEXT WARNINGS AT 060900Z AND

062100Z.//

It all depends on how quickly this ridge develops. Obviously, the longer it takes to develop, the more likely Helen will make landfall on the Cape York Peninsula. But if it does develop and manage to exert a steering influence on Helen quickly enough then Helen could well meander over the warm waters of the GOC and possibly head back towards Darwin (although this is highly unlikely and would only occur if there was a prolonged reversed steering motion).

The BOM seems to be forecasting the ridge to the south being slower to develop ensuring landfall on the Cape York Peninsula but once it does develop they have Helen moving slowly southward over land giving the region a prolonged severe rainfall event, perhaps extending as far south as Cairns.

See here for BOM updates: http://www.bom.gov.au/weather/cyclone/index.shtml

Overall, it's a forecasting nightmare. The future track of an already erratic Helen is very uncertain. Plenty to watch over the coming days.

Thanks for those updates Cookie, they will be very useful over the coming days. Yes, there certainly has been a lot of flooding Icer, along with fallen trees, widespread blackouts and other damage. And Helen isn't even done yet!

Edited January 6, 2008 by Somerset Squall

[Icer]

Update

Update 2

For waters East of Cape Don.

Issued at 5:10 pm CST on Sunday 6 January 2008

Synoptic situation

At 3:30 pm CST Ex-Tropical Cyclone Helen was within 30 nautical miles of 14.4 S 140.5 E about 240 nautical miles east of Alyangula with central pressure 995 hectopascals moving south southeast at 12 knots.

The centre is forecast to be over land within 130 nautical miles of 17.3 S 141.2 E at 3:30 am CST Monday.

Gale Warning

Cape Don to Cape Shield

Southwest to northwest winds 25/35 knots offshore. Seas 3 to 4 metres. Swell to 2 metres. Scattered squalls with gusts to 50 knots.

Strong Wind Warning

Cape Don to the Queensland Border

Southeast to southwest winds 20/30 knots. Seas 2.5 to 3m. Scattered squalls with gusts to 45 knots.

These conditions should persist for at least another 24 hours.

The Warning between Cape Fourcroy and Cape Don has been cancelled.

The next warning will be issued by 11:00 pm CST.

Please be aware

Wind gusts can be a further 40 percent stronger than the averages given here, and maximum waves may be up to twice the height.

-------------------------- End of warning ----------------------------

[Somerset Squall]

The solutions have changed again this morning. The JTWC have issued a final warning on Helen as she degenerates into a remnant low. They are not expecting her to re-develop now before her remnants make landfall on the Cape York Peninsula. I think I favour this solution as Helen is no more than a small cluster of showers now and they are moving rapidly eastwards towards land.

The BOM however, have also changed their minds regarding the remnant low of Helen. Unilke the last advisory, they are now latching onto the idea of a fast building ridge to the south which will force Helen's remnants southward before landfall in the CYP. They expect Helen to re-develop into a tropical cyclone just before landfall in Gibert River Mouth.

So who knows? Two very different forecasts compared to last night. The models are still all over the place too. So, a case of wait and see. I do, however, favour the JTWC's forecast as Helen is highly disorganised and is moving towards land pretty quickly.

[Cookie]

thanks for you'r great updates as ever been very inresting watching this.

[Somerset Squall]

Certainly has Cookie- thanks.

BOM have now fallen into line with JTWC and predict that the remnants of Helen will not re-organise and will dissapate when they make landfall in the next 6 hours. So unless there is anymore surprises, Helen's days are over.

Latest news: http://www.abc.net.au/news/stories/2008/01...ction=australia

[Icer]

Image 1

Image 2

I agree Cookie been good to watch would like to be there though!

[Icer]

Update

Moving away now...