Seminole Posted September 8, 2017 Share Posted September 8, 2017 ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM Hurricane Irma Discussion Number 37 NWS National Hurricane Center Miami FL AL112017 500 AM EDT Fri Sep 08 2017 Microwave images and data from an Air Force Reserve Hurricane Hunter aircraft indicate that Irma is currently undergoing an eyewall replacement cycle. A recent GMI overpass showed an 50 nmi wide outer eyewall, with the inner eyewall weakening. The Hurricane Hunter aircraft reported peak 700-mb winds of 147 kt in the outer eyewall near 0500 UTC, and maximum SFMR winds were in the 125-130 kt range. Based on these data, the initial intensity is reduced to 135 kt. Irma is forecast to remain in a favorable warm water, light shear environment for the next 36-48 h. The intensity guidance shows a slow weakening during this time, but Irma is expected to remain at least a Category 4 hurricane until landfall in Florida. After landfall, a fairly quick decay in maximum winds is expected due to land interaction and increased shear, although Irma's large wind field is likely to still produce hurricane-force winds over a large area. There are two caveats to the intensity forecast. First, some additional weakening could occur during the eyewall replacement, followed by re-intensification as the cycle completes. Second, the ECMWF, UKMET, and NAVGEM forecast a track over or close to the coast of Cuba that is not currently a part of the track forecast. If this occurs, Irma could be weaker than currently forecast along the later parts of the track. The initial motion is west-northwestward or 285/14. Irma should maintain this general trajectory for the next 24-36 h as it moves along the southwestern side of the subtropical ridge. After that time, the guidance is in good agreement that the ridge should break and allow Irma to turn north-northwestward to northward. There remains some spread between the models on when the turn will occur, with the GFS/Canadian being on the eastern side of the guidance and the UKMET/NAVGEM on the left side. The ECMWF, Florida State Superensemble, and the HFIP Corrected consensus are in the middle of the guidance envelope, and the new track forecast is in best agreement with those models. Overall, the new forecast track is similar to the previous forecast, with minor westward adjustments at 36 and 48 h. Link to comment Share on other sites More sharing options...
csnavywx Posted September 8, 2017 Share Posted September 8, 2017 Cloud top temps definitely coming back down. ERC may be near completion. Link to comment Share on other sites More sharing options...
Seminole Posted September 8, 2017 Share Posted September 8, 2017 Based on the NHC 5:00 AM discussion and recent satellite presentation it does appear that the ERC has completed and Irma's wind field is expanding. Link to comment Share on other sites More sharing options...
Hurricane Agnes Posted September 8, 2017 Share Posted September 8, 2017 Link to comment Share on other sites More sharing options...
WNC_Fort Posted September 8, 2017 Share Posted September 8, 2017 6z GFS slightly SW through 54. going to be a devastating run for FL Link to comment Share on other sites More sharing options...
nycsnow Posted September 8, 2017 Share Posted September 8, 2017 Gfs looks like euro Link to comment Share on other sites More sharing options...
UpstateSCBud Posted September 8, 2017 Share Posted September 8, 2017 GFS is definitely more SW through 60 as well. Falling in line with the EURO so far Link to comment Share on other sites More sharing options...
nycsnow Posted September 8, 2017 Share Posted September 8, 2017 Gfs is a disaster run Link to comment Share on other sites More sharing options...
Snowman99 Posted September 8, 2017 Share Posted September 8, 2017 GFS right up the spine. Link to comment Share on other sites More sharing options...
Wild Weather Monger Posted September 8, 2017 Share Posted September 8, 2017 And once again, the GFS forecast large pressure falls when the right turn occurs to sub 900mb. Link to comment Share on other sites More sharing options...
delijoe Posted September 8, 2017 Share Posted September 8, 2017 GFS comes ashore around Key Largo/Islamorada and up through the middle right through Orlando! I have a friend in Kissimmee who's going to be in real trouble if this verifies. Could see major damage to the theme parks as well which would destroy the state's economy for years... Link to comment Share on other sites More sharing options...
csnavywx Posted September 8, 2017 Share Posted September 8, 2017 Recon pass still shows an inner eyewall max, but it is definitely weaker than the last mission. OEW steadily strengthening. Should complete sometime today, probably earlier rather than later. Link to comment Share on other sites More sharing options...
Casualbrain Posted September 8, 2017 Share Posted September 8, 2017 This run is giving me heartburn - Mylanta isn't the cure for Irma however. Today's Max-Wind, Min-Pressure chart: Link to comment Share on other sites More sharing options...
Crazy4Wx Posted September 8, 2017 Share Posted September 8, 2017 Looks like there is nowhere to go in the entire state of Florida. it will also strengthen right up till Landfall if it can avoid Cuba. The environment is too favorable. Link to comment Share on other sites More sharing options...
Mountain_Patch Posted September 8, 2017 Share Posted September 8, 2017 3 minutes ago, csnavywx said: Recon pass still shows an inner eyewall max, but it is definitely weaker than the last mission. OEW steadily strengthening. Should complete sometime today, probably earlier rather than later. Everything I'm reading is telling me the only thing that's holding it back from being 190 mph is size. Looking at angular momentum, and the friction seems to say that it could reach back to cat 5 but it'll never be 190 mph at this size. Also fascinating to read that hurricanes this large are able to deal with dry air/shear much better than their smaller counterparts even if they have higher winds. Link to comment Share on other sites More sharing options...
UpstateSCBud Posted September 8, 2017 Share Posted September 8, 2017 6 minutes ago, Crazy4Wx said: Looks like there is nowhere to go in the entire state of Florida. it will also strengthen right up till Landfall if it can avoid Cuba. The environment is too favorable. Western panhandle of FL appears to be the safest spot. Can't really escape into GA either. Link to comment Share on other sites More sharing options...
Casualbrain Posted September 8, 2017 Share Posted September 8, 2017 Harvey's impact was rain because of it's huge fetch of tropical moisture and slow movement. Irma's impact will be high winds + long duration. Almost 24 hours of 'cane force winds in Miami - that has never happened before, and doesn't happen with smaller diameter storms. The fact we get two historic hurricanes at the start of a hurricane season after a LONG dry spell is rather sobering - people forget how insane these kind of storms are after the longest Cat2+ hurricane lull in US history... Link to comment Share on other sites More sharing options...
csnavywx Posted September 8, 2017 Share Posted September 8, 2017 Raw/ADJ T# back up to 6.6 (from 6.2 earlier). Wouldn't be surprised to see a pressure drop re-commence once this IEW weakens a bit more. Link to comment Share on other sites More sharing options...
No snow for you Posted September 8, 2017 Share Posted September 8, 2017 Florida is going to have a problem financially. Looking at their financial statements for their wind and hail pool they only have total assets of 21 billion and when you strip out liabilities it is around 9 billion. I can't find if they have reinsurance but if they don't the state is going to have a real problem Link to comment Share on other sites More sharing options...
Crazieman Posted September 8, 2017 Share Posted September 8, 2017 3 minutes ago, Casualbrain said: Harvey's impact was rain because of it's huge fetch of tropical moisture and slow movement. Irma's impact will be high winds + long duration. Almost 24 hours of 'cane force winds in Miami - that has never happened before, and doesn't happen with smaller diameter storms. The fact we get two historic hurricanes at the start of a hurricane season after a LONG dry spell is rather sobering - people forget how insane these kind of storms are after the longest Cat2+ hurricane lull in US history... Nah. Church of Gaia indicates we're overdue for Carbon Punishment. Nobody expected the Climate Inquisition. Link to comment Share on other sites More sharing options...
Paragon Posted September 8, 2017 Share Posted September 8, 2017 4 hours ago, 40/70 Benchmark said: I understand that, but the point is that this particular IRC has manifested itself in this manner. It's very difficult to get a storm back up to Cat 5 after it has been there and then weakened some. Andrew did it, but that was reclassified after the fact. I think David actually got to Cat 5 three times, but that's an extreme rarity. Anyway Irma has set some amazing records, it peaked at 185 mph and stayed there for 36 hours, which is twice as long as any other hurricane in Atlantic basin recorded history (David did it for 18 hours.) You don't expect a storm to stay at Cat 5 all the way to the coast anyway, especially when it becomes a Cat 5 so far away from the mainland. It'll still have Cat 5 surge damage though, regardless of wind speeds. Link to comment Share on other sites More sharing options...
Casualbrain Posted September 8, 2017 Share Posted September 8, 2017 Just now, Crazieman said: Nah. Church of Gaia indicates we're overdue for Carbon Punishment. Nobody expected the Climate Inquisition. I can see it now - new hurricane name list per Rex Tillerson: Andarko Berry Conoco Devon Exxon.... Link to comment Share on other sites More sharing options...
csnavywx Posted September 8, 2017 Share Posted September 8, 2017 URNT12 KWBC 081002 VORTEX DATA MESSAGE AL112017 A. 08/09:37:12Z B. 21 deg 38 min N 074 deg 05 min W C. NA D. 109 kt E. 278 deg 18 nm F. 022 deg 132 kt G. 276 deg 22 nm H. 927 mb I. 11 C / 3076 m J. 16 C / 3513 m K. 16 C / NA L. CLOSED M. C40 N. 12345 / NA O. 0.1 / 1 nm P. NOAA2 2011A IRMA OB 04 MAX FL WIND 132 KT 276 / 22 NM 09:31:30Z CNTR DROPSONDE SFC WIND 170 / 10 KTS New eye is big. Going to take a while to shrink that. Unfortunately, Irma's got a while to do so. On the upside, that inner core is big and that may give it a chance to interact with Cuba a bit if it hangs on the left side of the cone. Link to comment Share on other sites More sharing options...
franklin NCwx Posted September 8, 2017 Share Posted September 8, 2017 3 minutes ago, No snow for you said: Florida is going to have a problem financially. Looking at their financial statements for their wind and hail pool they only have total assets of 21 billion and when you strip out liabilities it is around 9 billion. I can't find if they have reinsurance but if they don't the state is going to have a real problem Feds will cover the rest. Link to comment Share on other sites More sharing options...
Morris Posted September 8, 2017 Share Posted September 8, 2017 The pressure has risen 8 mb since last night. It might only be a Cat 3 at this moment. Link to comment Share on other sites More sharing options...
RU848789 Posted September 8, 2017 Share Posted September 8, 2017 13 minutes ago, UpstateSCBud said: Western panhandle of FL appears to be the safest spot. Can't really escape into GA either. Yeah, but the storm will be a Cat 1 by the time it reaches the FL/GA line, so that should be far enough north in any decent building. Link to comment Share on other sites More sharing options...
LakeEffectKing Posted September 8, 2017 Share Posted September 8, 2017 Depending on the interaction with Cuba, you may see some frictional convergence tighten the eye up a bit (increase in max winds near the core) as it approaches the Keys...most of the models show a robust deepening pressure wise, but how that translates into max winds at the core is the big question. Link to comment Share on other sites More sharing options...
msuwx Posted September 8, 2017 Share Posted September 8, 2017 Barring negative interaction in some way with Cuba, I think Irma has a very good chance at strengthening over the next 24 hours or so. It's a big hurricane, so there's a limit to some extent, but I think the pressure could drop a decent amount. Link to comment Share on other sites More sharing options...
Crazy4Wx Posted September 8, 2017 Share Posted September 8, 2017 When do we start to favor those short range models? Link to comment Share on other sites More sharing options...
dan11295 Posted September 8, 2017 Share Posted September 8, 2017 I agree, best hope for Florida is it keeps going a bit left and weakens due to Cuba interaction prior to the N turn. Link to comment Share on other sites More sharing options...
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