Srain Posted January 10, 2012 Share Posted January 10, 2012 Please. It's not like you get excited about Cat 5s on this side, either. I barely remember you posting about Yasi last year. But when it comes to sleet in Houston, oh boy! Unlike you, I have a life beyond interest in all things tropical. I do have 'local' interests as well, you know. Texas City had a possible tornado very near where you where during Ike, yesterday. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 10, 2012 Author Share Posted January 10, 2012 Unlike you, I have a life beyond interest in all things tropical. I do have 'local' interests as well, you know. C'mon. Texas City had a possible tornado very near where you where during Ike, yesterday. Ha! I read about that and of course remembered being there. It was kind of trippy thinking about it. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 10, 2012 Author Share Posted January 10, 2012 Cyclone Heidi has formed, and it's headed for the Pilbara coast. It's a crappy, asymmetric system, and I get the impression that even the BoM isn't convinced it's purely tropical. The shear should increase as it approaches the coast, so no real strengthening is forecast: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Heidi is strengthening as it approaches the coast near Port Hedland. Latest BoM intensity is 990 mb/45 kt (10-min), and it's expected to reach Cat 2 (strong TS) before making landfall tonight. The JTWC's current assessment and forecast are in close agreement with the BoM: Link to comment Share on other sites More sharing options...
Roger Smith Posted January 11, 2012 Share Posted January 11, 2012 Radar loop: http://www.bom.gov.au/products/IDR162.loop.shtml#skip Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Heidi is strenghtening-- now a Cat 2 with an intensity of 986 mb/50 kt (10-min). More intensification is possible before the center crosses the coast near Port Hedland withing the next 12 hr. On the American scale, this is approaching hurricane strength. Thanks, Roger, for the radar link. The latest still shows a well-defined core and some good rainbands. A nice little system: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Here are the latest conditions from Port Hedland: http://www.bom.gov.a...801.94312.shtml The cyclone's center should cross the coast pretty near this town, so we should see some good obs. Peak gust so far: 34 kt. Link to comment Share on other sites More sharing options...
Ed Lizard Posted January 11, 2012 Share Posted January 11, 2012 Oz Cyclone Chasers have detailed Euro map that shows weakening through landfall. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 The latest advice indicates the pressure has lowered to 980 mb-- however, the radar signature looks to me like it's becoming a tad less distinct on the last few frames. Motion has slowed a bit-- and that will delay landfall a little. The advice warns of gusts up to ~75 kt near where the center crosses-- including the Port Hedland area. The highest gust at the Port Hedland Airport has been 34 kt, with the pressure holding more or less steady over the last several hours. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 By the way, Bedout Island-- right in the cyclone's core (see radar)-- just reported 53 kt (10-min) gusting to 61 kt. This is a healthy cyclone: http://www.bom.gov.au/products/IDW60801/IDW60801.94310.shtml Link to comment Share on other sites More sharing options...
am19psu Posted January 11, 2012 Share Posted January 11, 2012 By the way, Bedout Island-- right in the cyclone's core (see radar)-- just reported 53 kt (10-min) gusting to 61 kt. This is a healthy cyclone: Wow. Tight cores FTW. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Wow. Tight cores FTW. Yeah. That is a solid reading. And it's interesting how it's right in that left "eyewall", as per the radar. Tight core, indeed! Interesting that the observed intensity is higher than the operational value (50 kt). Why doesn't that ever happen in our basins? Grrrr. Link to comment Share on other sites More sharing options...
am19psu Posted January 11, 2012 Share Posted January 11, 2012 Interesting that the observed intensity is higher than the operational value (50 kt). Why doesn't that ever happen in our basins? Grrrr. Because we'd have had at least one plane in the system for the last 24 hours continuously? Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Because we'd have had at least one plane in the system for the last 24 hours continuously? So the recon-measured intensity will always be higher than the Dvorak estimate? Link to comment Share on other sites More sharing options...
am19psu Posted January 11, 2012 Share Posted January 11, 2012 So the recon-measured intensity will always be higher than the Dvorak estimate? Always be more accurate Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Always be more accurate Agreed. But, still-- it is interesting the way our surface obs almost never reach the best-track or operational values, whereas it does happen in Oz. Perhaps they're just more conservative in their overall approach to assessing intensity? Link to comment Share on other sites More sharing options...
am19psu Posted January 11, 2012 Share Posted January 11, 2012 Agreed. But, still-- it is interesting the way our surface obs almost never reach the best-track or operational values, whereas it does happen in Oz. Perhaps they're just more conservative in their overall approach to assessing intensity? No, I'm saying the error bars are larger in Oz because they only have Dvorak so it is much more likely that they can underestimate a storm than NHC. When you have synoptic surveillance missions, you are likely getting close to the actual Vmax at flight level, so it's going to be a lot harder for NHC to underestimate it. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 No, I'm saying the error bars are larger in Oz because they only have Dvorak so it is much more likely that they can underestimate a storm than NHC. When you have synoptic surveillance missions, you are likely getting close to the actual Vmax at flight level, so it's going to be a lot harder for NHC to underestimate it. So you're saying that the BoM will always underestimate-- but not overestimate? Can't Dvorak estimates misfire in both directions? Also, I remember reading something about the BoM's methdodology for upgrades, and it actually is a bit different, if I remember correctly. For example, they require a system to maintain winds of 34 kt (10-min) for a specific number of hours before upgrading it to a cyclone, whereas I believe the NHC just needs a single, moment-in-time instance or estimate of the threshold speed. I'll try to dig up that info. Link to comment Share on other sites More sharing options...
am19psu Posted January 11, 2012 Share Posted January 11, 2012 So you're saying that the BoM will always underestimate-- but not overestimate? Can't Dvorak estimates misfire in both directions? Also, I remember reading something about the BoM's methdodology for upgrades, and it actually is a bit different, if I remember correctly. For example, they require a system to maintain winds of 34 kt (10-min) for a specific number of hours before upgrading it to a cyclone, whereas I believe the NHC just needs a single, moment-in-time instance or estimate of the threshold speed. I'll try to dig up that info. I'm saying their errors will be larger in general. Absolutely Dvorak can misfire in both directions (though to me at least, it seems to have a low bias for smaller systems). I believe you are correct re: the duration of time. The only time standard NHC uses relates to central convection, not winds. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 I'm saying their errors will be larger in general. Absolutely Dvorak can misfire in both directions (though to me at least, it seems to have a low bias for smaller systems). I believe you are correct re: the duration of time. The only time standard NHC uses relates to central convection, not winds. Yeah, I've read some papers Re: wind/pressure relationships that talk about how Dvorak tends to underestimate microcane intensities. So maybe Heidi is an example. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Yeah, I've read some papers Re: wind/pressure relationships that talk about how Dvorak tends to underestimate microcane intensities. So maybe Heidi is an example. Jova as well. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Most-recent radar shot shows some nice, strong banding features coiled around a tight core. The apparent crappiness of the N semicircle is at least partially due to simple attenuation: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Bedout Island just reported 60 kt! If that reading is accurate, this thing is getting close to Cat 3! The new BoM advice upped the winds to only 55 kt. I think they might want to consider upgrading Heidi, as it's highly unlikely Bedout Island sampled the absolute highest wind. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Winds at Bedout Island are down to 45 kt, and the pressure is up to 993 mb and rising. The low pressure of 987 mb coincided with the max wind of 60 kt, which occurred as the center passed just to the W. Winds in Port Hedland are now pegged at over 25 kt, with consistent gusts to gale force. It seems to me that the cyclone has a very small core: Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Adam and Jorge don't appreciate Heidi's hawtness. Link to comment Share on other sites More sharing options...
wxmx Posted January 11, 2012 Share Posted January 11, 2012 Adam and Jorge don't appreciate Heidi's hawtness. Not even boomer is posting...that should be a hint. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Not even boomer is posting...that should be a hint. Boomer only likes Queensland threats. He's as interested in the Pilbara as he is in Texas. Link to comment Share on other sites More sharing options...
Srain Posted January 11, 2012 Share Posted January 11, 2012 Boomer only likes Queensland threats. He's as interested in the Pilbara as he is in Texas. Link to comment Share on other sites More sharing options...
Ed Lizard Posted January 11, 2012 Share Posted January 11, 2012 Not sure of my pressure relationships for the basin, or even how to calculate up a 10 minute sustained to a 1 minute sustained, but this is a hurricane if a high end Cat 2 is ~70 mph/10 minutes. That is worth being interested. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted January 11, 2012 Author Share Posted January 11, 2012 Not sure of my pressure relationships for the basin, or even how to calculate up a 10 minute sustained to a 1 minute sustained, but this is a hurricane if a high end Cat 2 is ~70 mph/10 minutes. That is worth being interested. Agreed. For our scale... Convert 10-min to 1-min using a factor of ~1.136. So 60 kt (10-min) = ~68 kt (1-min)-- a solid Cat 1 for us. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.