Super Typhoon Rammasun

[Somerset Squall]

The third tropical depression of the West Pacific season has formed, to the east of the Phillipines. A general northwards track is anticipated, along the western side of a subtropical ridge to the east. Steady intenisifcation is also expected (only steady due to it's size), in response to low shear and good ocean heat content. TD03W isn't expected to affect land, at least for now.

Image of TD03W (East of Phillipines):

[Cookie]

tracking map of this storm!

[Somerset Squall]

Thanks Cookie, a fairly unusual straight northwards track predicted as that image shows.

The depression has been upgraded to a tropical storm, named Rammasun. As Rammasun has become much better organised over the last 6 hours, JTWC have upped the intensity estimates for the storm, expecting a peak of 90kts, so this system has a fair chance of becoming a typhoon. Convection is more consolidated over the centre and convectional banding has improved, and as conditions should remain favourable with very good radial outflow then Rammasun could spin up fairly quickly. Around 120hrs, Rammasun should begin extratropical transition.

[Cookie]

Im very pleased this at the moment dosent look like it could affect land, and after last weekend I hope it stays like that!

[Somerset Squall]

Im very pleased this at the moment dosent look like it could affect land, and after last weekend I hope it stays like that!

You can say that again Cookie!

Rammasun has continued strengthening today, albeit slowly, and is now at 55kts. The circulation centre was fairly broad earlier with other smaller embedded circulations noted rotating around the main centre. Rammasun has become much better organsied this evening though with persistant, deep convection over the centre and some reletively good banding features becoming evident. It's pretty likely that Rammasun will strengthen to typhoon status tommorrow as sea temps remain high along the northward track, shear remains low and outflow remains good. JTWC expects a peak of 95kts. Extratropical transition is expected to begin by 96hrs as shear increases, sea temps lower and dry air becomes entained into the storm. Completion of ET is expected by 120hrs where Rammasun could become a fairly potent extratropical cyclone.

Latest image of Rammasun:

Taken from NAVY/NRL

[kold weather]

Not a bad looking system but a little asymeteric at present with the deep convection mainly on the southern side. Despite that steady development looking a good bet as its developing good cyclonic curveature right now and has good looking inflow channels as well. Center of circulation on the northern part of the deep convection, how strong this will get with this sort of presentation will depend on the size of the circulation. If its small then it won't matter too much and the whole thing will wrap very tightly around. If its got a flabby center then its going to take its time to strengthen as the convection wont be able to wrap as well on that northern side.

I should think that 80-90kts seens reasonable at this point, maybe a little higher if it has a tight circulation as it goes over very high heat content but right now I think that sort of range is pretty decent providing no unexpected shear develops along the path.

[Cookie]

thanks for the updates guys

[kold weather]

Well Rammasun has continued to develop pretty decently over the last 24hrs with sat.estimates now at 80kts. A large eye has formed and in the last 12hrs the convection has finally been able to wrap round the northern side to the system though the southern side is still the strongest section of the system with some fairly deep convection in the southern eyewall.

I still think the max will be about 80-90kts but given it has strengthened well over the past 12hrs and there is a patch of higher heat content coming up for the system in about 24hrs it may end up a touch stronger then that.

[Cookie]

I've got to ask on the tracking map I posted whats with the sudden swing?

[Somerset Squall]

Rammasun has intensified rapidly over the last 6 hours and is now a cat 3, 100kt typhoon. This intensification is because of a good poleward outflow channel, high sea temps, low shear and good diffluence aloft. Rammasun is forecasted to peak at 115kts (cat 4) on a northward track before higher shear and dry air initiates extratropical transition. A faster track northeastwards will occur around this time as Rammasun rounds the periphery of the steering ridge to the east and begins to be approached by a trough (which is the cause of the progged high shear aswell). This may be the "swing" you refer to Cookie?

[Cookie]

yup it is thanks for explaining mate

[kold weather]

Yep Now looks like a very well organised typhoon, I'd be quite comfortable with i being around 140kts right now and I wouldn't be surprised if thats the case. Once again I've underestimated the effect that the sharp increase in heat content the system has had in the last 18hrs or so has had on the system and its strength. The outflow channel also developed very well which wasn't really the case at all when I made my post yesterday afternoon, theres a chance that we could see our first super thypoon from this given the excellent organisation.

Anyway I busted with the strength of this system but then again this is the first time I've really tracked WPAC systems and they tend to become stronger more readily then Atlantic systems anyway thats probably why I was way too conservative given the high heat content present and low shear.

Certainly looking impressive though totally different looking system to Nargis both are probably close to the same strength as one another IMO, two beasts in the space of a week or so, impressive...

Edited May 10, 2008 by kold weather

[Somerset Squall]

Indeed, we now have a super typhoon, with an estimated intensity of 135kts, just shy of monsterous cat 5 status (it may well even be there). Thank goodness Rammasun isn't going near land. The super typhoon is currently in very good conditions with good radial outflow but soon Rammasun will be carried northeastwards by westerlies and then become quite a significant extratropical storm.

Latest image of the very impressive Super Typhoon Rammasun:

[Cookie]

WOW is all I can say, but this has worried me a bit!

Storm Alert issued at 10 May, 2008 18:00 GMT

Typhoon RAMMASUN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Green Alert Country(s) or Province(s)

Japan

probability for TS is 35% in about 72 hours

[Somerset Squall]

WOW is all I can say, but this has worried me a bit!

Yeah, it may get pretty close to Japan but I expect it to be extratropical by then. JTWC now expect Rammasun to be extratropical by 48hrs- the waters near Japan are still far too cold to support a tropical system.

Rammasun has weakened this morning with a lowered intensity of 115kts. Still looks fairly impressive on sattelite imagery but the northwest quadrant (nearest the approaching trough) looks like it is being eroded by higher shear or dry air, and this will continue as Rammasun picks up a faster northeastward track. Coupled with colder waters, these negative factors should induce extratropical transition by 36hrs which will be complete by 48hrs. Rammasun has potential to be a fairly deep extratropical storm which will brush by southeastern Japan early next week but I don't really expect it to cause many problems.

Satellite image of Rammasun:

Taken from NAVY/NRL

[Cookie]

thats good to know

Storm Alert issued at 11 May, 2008 0:00 GMT

Typhoon RAMMASUN is forecast to strike land to the following likelihood(s) at the given lead time(s):

Green Alert Country(s) or Province(s)

Japan

probability for TS is 35% in about 48 hours

[Somerset Squall]

Rammasun has continued to rapidly weaken under the influence of high shear and low sea temps. Rammasun is now becoming an extratropical cyclone as it interacts with the baroclinic zone. Drier, colder air is expected to effect Rammasun's circulation and remove tropical characteristics by making it into a cold cored system. JTWC expect extratropical transition to be completed within 24hrs, perhaps as soon as 12.

Latest image of Rammasun shows the eye has dissapeared and the system as a whole becoming a lot larger in size, a characteristic of an extratropical storm:

[Cookie]

looks a right mess now.