ATL: IRMA - Post-Tropical - Discussion

[ronjon]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida. Yes I know all about the cone and uncertainty and by that narrow definition they were correct. However, it seemed to me, and others chime in, that they rather stubbornly hung their hat on the Euro when other models like GFS and UKMET were much closer to the actual track. Had they used a blend the track would have much closer. Secondly, I suppose the science may just not be there yet on storm surge predictions. Some of the inaccuracy was indeed due to the storm actually tracking east up the center of the state and I suppose other factors were just a weaker storm but the 10-15 feet prediction for the SW coast was at least twice as large as observed. Again this isn't a bash or rant, just some honest assessment of predictions versus reality. I know they'll be some reanalysis in the future and perhaps they'll be some lessons learned to improve the forecast in the future.

[Orlando]

I evacuated to Chattanooga, TN. I will be here for awhile. We are having serious wind gusts. It has rained all day. I am with family on a mountain NE of town. I would be willing to bet that the gusts are greater than 50 mph. It is a bit scary.

Anyone with Orlando news, please let us know.

[WeatherGuesser]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida.

I imagine there will be a lot of finger pointing and second guessing, maybe some job changes if not career changes. Did I read here that some on air Met told people to return their supplies ... just before they ended up in the thick of it?

[GalvestonWXGeek]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida. Yes I know all about the cone and uncertainty and by that narrow definition they were correct. However, it seemed to me, and others chime in, that they rather stubbornly hung their hat on the Euro when other models like GFS and UKMET were much closer to the actual track. Had they used a blend the track would have much closer. Secondly, I suppose the science may just not be there yet on storm surge predictions. Some of the inaccuracy was indeed due to the storm actually tracking east up the center of the state and I suppose other factors were just a weaker storm but the 10-15 feet prediction for the SW coast was at least twice as large as observed. Again this isn't a bash or rant, just some honest assessment of predictions versus reality. I know they'll be some reanalysis in the future and perhaps they'll be some lessons learned to improve the forecast in the future.

What exactly do you mean "had they used a blend"? I'm not familiar with how the NHC actually forms their path analysis. You seem to imply that the NHC discarded all models except for the Euro. Is this true? For some reason, I think your statement is terribly flawed (especially considering you state that NHC "blew it" and then follow that up with an admission that the NHC "were correct". Which is it?

Yes, the OP's statement tweaked my last nerve.

[Michele B]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida. Yes I know all about the cone and uncertainty and by that narrow definition they were correct. However, it seemed to me, and others chime in, that they rather stubbornly hung their hat on the Euro when other models like GFS and UKMET were much closer to the actual track. Had they used a blend the track would have much closer. Secondly, I suppose the science may just not be there yet on storm surge predictions. Some of the inaccuracy was indeed due to the storm actually tracking east up the center of the state and I suppose other factors were just a weaker storm but the 10-15 feet prediction for the SW coast was at least twice as large as observed. Again this isn't a bash or rant, just some honest assessment of predictions versus reality. I know they'll be some reanalysis in the future and perhaps they'll be some lessons learned to improve the forecast in the future.

I think they do the best they can with tools available ATM.

I don't know if there is any way they could possibly know every "butterfly flutter" that goes into making a storm move way further east than predicted, or become so much weaker than anticipated.

I don't Want to sound
Like i was in 100% agreement with what we got, but I sure wouldn't t want to have to know for certain that I needed to sound an alarm and move 5 or 7 million people out of
Harms' way and do it in only a week or less.

[Steve]

I can't knock the NHC. The European was beating their forecasts and did for a week plus. They might have hedged the track a hair East twice in the last 24 hours, but they were close, and the verifications show they were highly competent. They expounded over and over and over in every discussion not to focus on the line. It's in every single set of bullet points. All the information anyone needed was there. JMO

[curtadams]

Irma isn't done yet here in Charleston SC. Multiple tornado warnings, sustained tropical force winds and some gusts to hurricane force. The Charleston Battery is under water and Charleston Emergency Services have suspended operations as it is too dangerous to go outside. This storm is far worse than what we experienced during Hurricane Matthew and the storm surge in downtown Charleston has surpassed that level during Hurricane Matthew.

The flooding in Charleston and Jacksonville seems pretty extreme for places so far from the eye and from any landfall. Could this be a tsunami-like wave that Irma pushed up earlier impacting the coast at the same time as the local effects?

[EquusStorm]

[galaxy401]

Gotten cloudy where I am from Irma. Amazing how massive the system is.

[stormreader]

I can't knock the NHC. The European was beating their forecasts and did for a week plus. They might have hedged the track a hair East twice in the last 24 hours, but they were close, and the verifications show they were highly competent. They expounded over and over and over in every discussion not to focus on the line. It's in every single set of bullet points. All the information anyone needed was there. JMO

The Euro was so much more consistently correct in the last 5-7 days with Irma than other models. Think that had to weigh in on their thinking. Now the track adjustment would have had to occur after landfall, while Irma was moving up the peninsula. By this time you would assume that everyone on the peninsula who is going to heed warnings, is already hunkered down and in place. Maybe I'm wrong, but don't know how much difference it would have made to alter the track at that time. So maybe that figured in their thinking. But Ronjon is right that the storm was obviously moving consistently east of the forecast track for quite a length of time, and the forecast was not altered. No bashing here from me either. Landfall was spot on.

[LAwxrgal]

Been away the last two days... not that I wanted to be... geez 2 major hurricanes, 2 major disasters in 2 weeks. And this is how we break our 12 year 'major' drought.

[pgoss11]

Irma isn't done yet here in Charleston SC. Multiple tornado warnings, sustained tropical force winds and some gusts to hurricane force. The Charleston Battery is under water and Charleston Emergency Services have suspended operations as it is too dangerous to go outside. This storm is far worse than what we experienced during Hurricane Matthew and the storm surge in downtown Charleston has surpassed that level during Hurricane Matthew.

The flooding in Charleston and Jacksonville seems pretty extreme for places so far from the eye and from any landfall. Could this be a tsunami-like wave that Irma pushed up earlier impacting the coast at the same time as the local effects?

Downtown Charleston
https://www.facebook.com/GlimpsesOfChar ... 471636676/

[1900hurricane]

Pretty crazy seeing the scope of the transitioning Irma vs Jose.

[tolakram]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida. Yes I know all about the cone and uncertainty and by that narrow definition they were correct. However, it seemed to me, and others chime in, that they rather stubbornly hung their hat on the Euro when other models like GFS and UKMET were much closer to the actual track. Had they used a blend the track would have much closer. Secondly, I suppose the science may just not be there yet on storm surge predictions. Some of the inaccuracy was indeed due to the storm actually tracking east up the center of the state and I suppose other factors were just a weaker storm but the 10-15 feet prediction for the SW coast was at least twice as large as observed. Again this isn't a bash or rant, just some honest assessment of predictions versus reality. I know they'll be some reanalysis in the future and perhaps they'll be some lessons learned to improve the forecast in the future.

The main issue is that the GFS was horrible up until the last day, then suddenly it was better and the euro was bad. We have just the main models, they use all kinds of different tools to blend the models together. Once Irma was less organized, post Cuba, the euro seemed to start having issues.

Here's the final model verification for Irma. AVNO is the GFS.



source: http://www.atmos.albany.edu/facstaff/tang/tcguidance/al112017/

If I were in their shoes I would have stuck closest to the model that was performing the best. You can see, though, that the euro outperformed the NHC at longer range so I doubt they were hanging their hats on it.

As far as surge and damage, I figured it would be a lot like Ike, with a spread out windfield capable of doing a lot of moderate damage to a wide area. Personally I didn't even consider the surge issue, and I can't find if there were any surge forecasts for places like Jacksonville or not.

[WeatherGuesser]

Outer edges of what's left moving through TN into W KY this evening, expecting winds in the 20s and 1-2" of rain.

[gailwarning]

Posted earlier from Rockledge in Brevard county. We lost a lot of shingles. Several patches right down to the wood. Ours is an older roof which I had inspected in April. There's a small cluster of homes around mine where there's a lot of lost shingles-- one roof is just 2 years old, while another is just two months old. The damage is exclusively on the south side of the homes. Could we have experienced a microburst? The rest of the subdivision has just scattered shingles lost.

[PaulR]

On our local TV News this evening, their meteorologist showed comparative night pictures from space, of roughly the south half of FL. One was I assume weeks or months ago, the other early this a.m. Except maybe for Miami, it looked like freaking South Korea, or Japan, vs. North Korea, I tried to find the pics online but so far have not. The story is not on our station’s website. Can anyone find & post the pics?

[storm_in_a_teacup]

I'm a huge supporter of the NHC and a scientist in real life but I have to say they blew it on Irma's track over Florida. Yes I know all about the cone and uncertainty and by that narrow definition they were correct. However, it seemed to me, and others chime in, that they rather stubbornly hung their hat on the Euro when other models like GFS and UKMET were much closer to the actual track. Had they used a blend the track would have much closer. Secondly, I suppose the science may just not be there yet on storm surge predictions. Some of the inaccuracy was indeed due to the storm actually tracking east up the center of the state and I suppose other factors were just a weaker storm but the 10-15 feet prediction for the SW coast was at least twice as large as observed. Again this isn't a bash or rant, just some honest assessment of predictions versus reality. I know they'll be some reanalysis in the future and perhaps they'll be some lessons learned to improve the forecast in the future.

The main issue is that the GFS was horrible up until the last day, then suddenly it was better and the euro was bad. We have just the main models, they use all kinds of different tools to blend the models together. Once Irma was less organized, post Cuba, the euro seemed to start having issues.

Here's the final model verification for Irma. AVNO is the GFS.

[i mg]https://i.imgur.com/zFJVuSb.png[/img]

source: http://www.atmos.albany.edu/facstaff/tang/tcguidance/al112017/

If I were in their shoes I would have stuck closest to the model that was performing the best. You can see, though, that the euro outperformed the NHC at longer range so I doubt they were hanging their hats on it.

As far as surge and damage, I figured it would be a lot like Ike, with a spread out windfield capable of doing a lot of moderate damage to a wide area. Personally I didn't even consider the surge issue, and I can't find if there were any surge forecasts for places like Jacksonville or not.

Ike counts as "moderate" surge? I was under the impression the surge damage from Ike was really bad (at least when I was in Galveston afterwards basically everything up to the first stories of buildings was gutted and there were boats and walls of debris piled on the highway). The only saving grace of Ike's surge was it was focused on the Bolivar Peninsula instead of going up the Houston Ship Channel. But Bolivar was completely wiped clean.

As far as computer models go it's not possible to reduce it to "let's go with this model over this one." As I have said before, numerical physics simulations can only be a guide, and so someone has to call it somewhere.

[Hypercane_Kyle]

Just got power back. The eye of Irma went over my house a few hours after landfall. My ears felt a funny pressure as the eye went over, so I'm guessing pressures were sub-950mb by the time it reached Hillsborough? EDIT: 952mb per NHC, I see. Saw winds of 80-85 sustained, with a gust or two up to 100mph. Lost a few trees, but no major damage to the house.

[bqknight]

I evacuated to Chattanooga, TN. I will be here for awhile. We are having serious wind gusts. It has rained all day. I am with family on a mountain NE of town. I would be willing to bet that the gusts are greater than 50 mph. It is a bit scary.

Anyone with Orlando news, please let us know.

About 50% of people with no power. Minor damage to signs, traffic lights, street signs. Lots of trees and branches down. Tons of people were out walking around after the curfew was lifted.