phil882 Posted February 12, 2012 Share Posted February 12, 2012 Latest JTWC package indicates some weakening has occurred-- winds are down to 100 kt-- but the forecast calls for some restrengthening, followed by landfall near Toamasina late Monday night with winds of 110 kt. Looks like the inner eyewall has finally cleared out, although the outer eyewall has recently opened up. It has got a lot of work to do to regain the strength it had earlier. I'm thinking this won't get much stronger than moderate cat 3 before landfall, if even that. Link to comment Share on other sites More sharing options...
phil882 Posted February 12, 2012 Share Posted February 12, 2012 Meanwhile... Jasmine track is about to get a little weird, looks like it will make an anticyclonic loop around a subtropical high. Believe it or not, this track can largely be blamed from the most recent strong MJO episode which really pumped up the ridge to the point that the storm couldn't escape into the westerlies. Also the JWTC no longer dissipates the system, and why should it, with it moving towards higher SSTs and lower shear under the upper level high, I think intensification beyond 24 hours is possible. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 Looks like the inner eyewall has finally cleared out, although the outer eyewall has recently opened up. It has got a lot of work to do to regain the strength it had earlier. I'm thinking this won't get much stronger than moderate cat 3 before landfall, if even that. Yeah, I was looking at the MW images before and I'm just not impressed. There are some serious structural issues-- like, a lot of asymmetry. I'm thinking Meteo France's more conservative intensity forecast might be the better one at this point. Link to comment Share on other sites More sharing options...
phil882 Posted February 12, 2012 Share Posted February 12, 2012 Yeah, I was looking at the MW images before and I'm just not impressed. There are some serious structural issues-- like, a lot of asymmetry. I'm thinking Meteo France's more conservative intensity forecast might be the better one at this point. Agreed. Part of the problem currently is that the storm's southern flank is interacting with a weakening upper level trough to its southeast, which is actually inducing a bit of southwesterly shear on the circulation at this time. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 Agreed. Part of the problem currently is that the storm's southern flank is interacting with a weakening upper level trough to its southeast, which is actually inducing a bit of southwesterly shear on the circulation at this time. Interesting the way these factors still can't be well-predicted even hours in advance. Intensity forecasting remains such a mystery. The latest Meteo France advisory lowers the initial intensity to 75 kt (10-min), and notes the "rather bad[ly] defined eye". It also indicates that significant intensification is no longer expected, bringing the cyclone ashore Monday night near Toamasina with winds of 70 kt. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 Not the tightest, sexiest-looking cyclone at this point: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 The JTWC still has this at 100 kt, and they bring it ashore at 100 kt as well, after some small fluctuations in intensity. The projected landfall point has shifted a bit to the S of Toamasina late tomorrow night. Interestingly, the forecast brings the center right over the inland capital, Antananarivo, at near-hurricane strength. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 La Reunion radar shot of Giovanna passing to the N. Looks much better than I would have expected: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 I can't find any recent MW images, but based on this shot and the La Reunion radar, it looks like Giovanna's restrengthening a tad. The structure has improved-- with a rounder, cleaner eye; better outflow to the W; and all-around better symmetry: Link to comment Share on other sites More sharing options...
phil882 Posted February 12, 2012 Share Posted February 12, 2012 I can't find any recent MW images, but based on this shot and the La Reunion radar, it looks like Giovanna's restrengthening a tad. The structure has improved-- with a rounder, cleaner eye; better outflow to the W; and all-around better symmetry: Yep... now that the trough has passed by to the east, the storm is regaining its symmetry and the eyewall is likely closed once again. I was surprised how quickly it regained its composure. Probably cat 4 or bust at this point. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 Yep... now that the trough has passed by to the east, the storm is regaining its symmetry and the eyewall is likely closed once again. I was surprised how quickly it regained its composure. Probably cat 4 or bust at this point. Wow-- you think? It does look pretty awesome now. It's a large eye, but it's very round and well-delineated. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 12, 2012 Author Share Posted February 12, 2012 The evening advisory from Meteo France has the intensity back up to 80 kt (10-min), noting the same structural improvements that we were just discussing. They peak it at 85 kt, then weaken it a little before landfall in ~24 hr-- however, they also note that they might have to up the intensity forecast if current trends continue. Re: the forecast track... It's been nudging a bit S, which lessens the threat to Toamisina (Tamatave), which I believe may miss the core to the N. Link to comment Share on other sites More sharing options...
tmagan Posted February 13, 2012 Share Posted February 13, 2012 Latest JTWC forecast for Madagascar looking pretty dire. Link to comment Share on other sites More sharing options...
tmagan Posted February 13, 2012 Share Posted February 13, 2012 Maximum sustained winds, per JTWC up to 145 mph. However, SSD has it at a T5.5. Sometimes I wonder if JTWC is overestimating the strength of storms in the area of their responsibility. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Maximum sustained winds, per JTWC up to 145 mph. However, SSD has it at a T5.5. Sometimes I wonder if JTWC is overestimating the strength of storms in the area of their responsibility. I notice in general they tend to be on the generous side, and their estimates are often a bit higher than the BoM's, for example. That having been said, I've seen the opposite happen, like with Cyclone Heidi. At landfall, the BoM had it at 60 kt (10-min), which converts to ~70 kt (1-min). The JTWC had it at 45 kt (1-min). It was puzzling. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Meteo France now has it at 100 kt (10-min), or a low-end Cat 4 on our scale. However, they suggest some weakening-- down to 85 kt-- before landfall from another ERC (which seems to be starting) and also increasing shear. They're mentioning the town of Andovoranto as the midpoint of the expected landfall zone: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Latest imagery. The MW looks good-- not amazing. When you compare this with earlier imagery, you can see that a new ERC is underway-- the inner eyewall is once again eroding: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Latest JTWC forecast for Madagascar looking pretty dire. It does, I agree-- but I think they're a bit bullish. Another ERC is occurring and it's also going to be hitting a little shear, so a 130-kt landfall seems unlikely to me. However, I do think it'll be a solid major. Another interesting thing about the JTWC forecast is that it brings the cyclone's center very close to the capital, Antananarivo, still as a solid hurricane. However, the worst of the cyclone should miss the port city, Toamasina, to the S: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 The latest advisory from Metro France has the intensity steady at 100 kt (10-min). They have the center on the coast (19.1S 49.0E) in 12 hr, just S of Andovoranto, with winds of 85 kt-- roughly a low-end Cat 3 on our scale. Residents are warned to expect gusts over 180 kph (~97 kt) within a 70-km radius of the center, mainly to the S. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 And the new JTWC warning is out as well. They keep the initial intensity at 125 kt (1-min) and suggest it may maintain that intensity up to landfall, if the current ERC doesn't complete. The 12-hr position is a bit inland with winds of 105 kt. The discussion describes a concentric-eyewall structure and 30-nmi eye. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Cool imagery showing Giovanna approaching the Madagascar coast. The MW image is mentioned in the JTWC discussion-- as it reveals an explicit double-eyewall structure. Based on these images, the port city, Toamasina (18.2S 49.4E), is going to at least see that outer eyewall on the weaker (right) side: Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 13, 2012 Share Posted February 13, 2012 ob FMMT 131500Z 26025KT 5000 -RA FEW007 BKN017 OVC090 25/24 Q0995 TEMPO 26030G50KT Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 ob FMMT 131500Z 26025KT 5000 -RA FEW007 BKN017 OVC090 25/24 Q0995 TEMPO 26030G50KT Oh, awesome-- thanks for posting this! I actually didn't realize they had a station. To anyone reading: this is Toamasina (Tamatave), Madagascar's main seaport. They should get the outer eyewall. Link to comment Share on other sites More sharing options...
CandymanColumbusGA Posted February 13, 2012 Share Posted February 13, 2012 Fascinating stuff... Impressive eye on IR: http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2012/02/120213_giovanna_ir_anim.gif Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 Fascinating stuff... Impressive eye on IR: http://cimss.ssec.wi...nna_ir_anim.gif Cool loop-- thanks! Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 <sigh> It looks like FMMT has stopped reporting-- just as it was getting interesting. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted February 13, 2012 Author Share Posted February 13, 2012 FMMT is reporting again: currently winds of 33 kt, pressure 991 mb and falling. Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 13, 2012 Share Posted February 13, 2012 <sigh> It looks like FMMT has stopped reporting-- just as it was getting interesting. ob FMMT 131700Z 28033KT 4000 RA FEW007 BKN017 OVC033 24/23 Q0991 Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 13, 2012 Share Posted February 13, 2012 FMMT is reporting again: currently winds of 33 kt, pressure 991 mb and falling. I didn't refresh... Link to comment Share on other sites More sharing options...
icebreaker5221 Posted February 13, 2012 Share Posted February 13, 2012 Fascinating stuff... Impressive eye on IR: http://cimss.ssec.wi...nna_ir_anim.gif Thanks for the loop! Been too busy to pay much attention to this, but it looks to me like the eye is clearing in the last frame. ERC almost complete? Also, eastern Madagascar is somewhat hilly, borderline mountainous (+2000 m). Anyone know how prone are they to mudslides from TCs that approach from the east? Link to comment Share on other sites More sharing options...
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