ATL: IDA - Remnants - Discussion

[CrazyC83]

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

In terms of the best track of Ida, here is what I would estimate.

AL092021, IDA, 24,
20210826, 0600, , TD, 15.6N, 77.9W, 30, 1008,
20210826, 1200, , TS, 16.4N, 78.8W, 35, 1006,
20210826, 1800, , TS, 17.2N, 79.5W, 35, 1006,
20210827, 0000, , TS, 18.1N, 80.1W, 40, 1005,
20210827, 0600, , TS, 19.2N, 80.9W, 45, 1002,
20210827, 1200, , TS, 20.3N, 81.7W, 55, 996,
20210827, 1730, L, HU, 21.5N, 82.6W, 75, 986,
20210827, 1800, , HU, 21.6N, 82.7W, 75, 986,
20210827, 2245, L, HU, 22.3N, 83.3W, 80, 983,
20210828, 0000, , HU, 22.5N, 83.5W, 75, 985,
20210828, 0600, , HU, 23.5N, 84.6W, 75, 986,
20210828, 1200, , HU, 24.5N, 85.7W, 75, 985,
20210828, 1800, , HU, 25.6N, 86.6W, 80, 978,
20210829, 0000, , HU, 26.7N, 87.6W, 95, 967,
20210829, 0600, , HU, 27.6N, 88.7W, 115, 949,
20210829, 1200, , HU, 28.5N, 89.6W, 135, 929,
20210829, 1655, L, HU, 29.1N, 90.2W, 130, 931,
20210829, 1800, , HU, 29.2N, 90.4W, 125, 932,
20210829, 1930, L, HU, 29.4N, 90.5W, 120, 934,
20210830, 0000, , HU, 29.9N, 90.6W, 105, 943,
20210830, 0600, , HU, 30.6N, 90.8W, 70, 972,
20210830, 1200, , TS, 31.4N, 90.8W, 45, 992,
20210830, 1800, , TS, 32.3N, 90.6W, 35, 997,
20210831, 0000, , TD, 32.9N, 89.8W, 30, 999,
20210831, 0600, , TD, 33.5N, 88.8W, 30, 997,

Landfalls: 27/1730 - Southern Isle of Youth
27/2245 - near Playa Dayaniguas, Cuba
29/1655 - Port Fourchon, LA
29/1930 - SE of Chauvin, LA

A few key points:

* The intensity around Cuba I believe was a bit higher. There was no Recon for a lengthy period, the satellite signature continued to improve and Recon data after emerging off Cuba suggested winds around 75 kt. For those reasons, I estimate the intensity to be 75 kt when it hit Isle of Youth and 80 kt when it hit western Cuba.

* The intensification in the Gulf is delayed a bit, but was even more rapid. In 18 hours, it rose from 80 kt to 135 kt and the pressure fell from 978 mb to 929 mb. The 135 kt intensity is largely based on flight-level winds of 148 kt, as SFMR readings (highest was 131 kt) aren't particularly reliable near shore.

* Based on surface data, the operational 130 kt intensity at landfall is retained and appears reasonable. Recon values supported a slightly lower intensity (around 125 kt) but the weight is given to the ship report.

[Woofde]

Once I back I'll try to upload some of the video of route 61 I took on my escape out. The damage was immense, especially from Kenner to Gramercy. Laplace was the worst, it looked like a warzone, roofs peeled, houses flooded, trees and powerlines snaped. Watching the residents being evacuated in an army truck was the worst part. They were devastated. It's going to be a long cleanup. They might as well be rebuilding their power infrastructure from zero in that area.

[Hurrilurker]

I think Ida will be upgraded to Cat 5 post analysis. A sustained wind found by an observation of 149mph is clearly an indicator that Ida was extremely powerful. Also this was recorded after Ida made landfall so I think it will be upgraded.
https://www.accuweather.com/en/hurrican ... ls/1006534

Your evidence of a cat 5 is actually evidence of a cat 4. I hope it's not upgraded. A high end cat 4 is horrific. One of the weak point of hurricane categories is the huge range for a cat 4. 130 and 155 are the same? That strikes me as crazy. I like the super typhoon designation at 150. Once you near that threshold...it's a total wipeout. A high end cat 4 (or worse) is total devastation.

Honestly, I wouldn't mind seeing a revamp of the Saffir-Simpson scale, or a whole new system, although I doubt it will happen because it messes up historical comparisons. For one thing Saffir-Simpson only goes up to 5 because it was meant to gauge infrastructure damage, but I think a scale of something like 10 units all the way from tropical depression (or maybe even disturbance) to ridiculous once in 1,000 years storm would be useful. Could tweak the ranges in the middle to be a little more fine-grained. Maybe even a weighted rating of pressure and winds, adjustments for basin base pressures, and some normalized way to track trends like a 3-day and 5-day moving average.

[Stormgodess]

Checking in... Husband made it to our house. Had to walk through flood waters and downed trees. Trees down all over property. At least 50 of them. But house is fine. Some water flowing under but not too high. One of the few trees remaining standing was the dead one I was so worried about. It's hard to describe feeling so blessed yet so heartbroken over the total destruction and suffering I see everywhere around me. But I know many of you know exactly how I feel right now. Love yall and thank you all from the bottom of my heart

[jhpigott]

08-29-2021 Lafourche Parish, LA - Aerial View of Widespread Damage

https://www.youtube.com/watch?v=Et_RBPw527M&t=205s

[PandaCitrus]

Grand Isle came out reasonably well all things considered. There's major damage and surge flooding but it's nothing like Mexico Beach after Michael. Many structures are still standing. I think people would have expected a lot worse. Whether because they barely missed the inner eye wall, rigorous building codes, or the earthen berms out in the ocean disrupted the surge, they came out about as well as you could have hoped.

https://pbs.twimg.com/media/E-D1CZqWYAU ... ame=medium

[IcyTundra]

Looks like Grand Isle got the worst of the storm surge but fortunately they managed to avoid the worst of the wind as the inner eye wall passed just to the west of Grand Isle. Unfortunately it looks like Lafourche Parish got the brunt of the inner eyewall and the wind damage is catastrophic across all of Lafourche Parish.

[Sciencerocks]

[AlphaToOmega]

The last advisory on Tropical Depression Ida has been issued by the NHC. Starting now, all Ida advisories will be issued by the Weather Prediction Center.

[MGC]

Furthermore, that 172 mph gust was not measured in the NE eyewall, which highlights that there could have been even higher gusts taking place there.

Those high gusts observed were likely in the numerous mesovortices embedded in Ida's eyewall IMO. I can't recall a major hurricane with mesovortices over land for so long. Andrew and Michael had them but I can't remember them lasting as long once inland. There is a small chance Ida was a Cat-5 when the pressure was 929mb but I think Ida will go down in the history books as a top end Cat-4.......MGC

[CrazyC83]

The last advisory on Tropical Depression Ida has been issued by the NHC. Starting now, all Ida advisories will be issued by the Weather Prediction Center.

Yet another "I" name that will never be heard from again after this.

[Craters]

I think Ida will be upgraded to Cat 5 post analysis. A sustained wind found by an observation of 149mph is clearly an indicator that Ida was extremely powerful. Also this was recorded after Ida made landfall so I think it will be upgraded.
https://www.accuweather.com/en/hurrican ... ls/1006534

Eh, I don't think that's very compelling evidence. Just one of the rare cases where a ground observation reading confirms what the recon was finding.

And then there's the question of what kind of gauge it was (i.e., a reliable model/brand or not), was it maintained correctly, was it calibrated recently, etc., etc., etc. Those are always the kinds of questions that those evaluating data have to wrestle with. I'd imagine it drives them bonkers after a while.

[Craters]

Brandon Ivey video of Ida causing destruction in Houma: https://youtu.be/uid654Nx8wE

Mods: This is off topic, so feel free to remove it.

It never ceases to amaze me how palm trees can withstand such astounding winds (loaded with rain, no less!) with that kind of grace, for lack of a better word.

[jasons2k]

I honestly expected Grand Isle to look like Holly Beach after Rita or High Island after Ike. But most of those structures with the metal roofs might indeed be newer buildings with better building codes. I’ve never been down there, so I just don’t know much about the place other than what I’ve read and discerned from photos. Some day, I hope to check the place out. I’m glad to see some things still standing!

[TheDreamTraveler]

Not sure how many live up north on the forums but look out for record flooding from Ida. Euro is showing almost a foot of rain right over my house in 2 days...all this falls in the span of 24 hours. this area is drenched from a wet summer, Fred and Henri dumping inches here as well. I already got a foot of rain the past 2 months. This could be one of the worst flooding events for a lot of areas in the mid atlantic and northeast

[Sanibel]

Strange mix of Poorly-built: Completely gone & Well-built/newer: Intact...


Hurricane Agnes rained 18 inches in that same area of Pennsylvania...

[SecondBreakfast]

Not sure how many live up north on the forums but look out for record flooding from Ida. Euro is showing almost a foot of rain right over my house in 2 days...all this falls in the span of 24 hours. this area is drenched from a wet summer, Fred and Henri dumping inches here as well. I already got a foot of rain the past 2 months. This could be one of the worst flooding events for a lot of areas in the mid atlantic and northeast

https://i.imgur.com/PcWbVrI.png

I’m up on Long Island, not looking forward to my commutes on Thursday. Wish we could send the rain to Lake Tahoe.

[TheDreamTraveler]

Strange mix of Poorly-built: Completely gone & Well-built/newer: Intact...


Hurricane Agnes rained 18 inches in that same area of Pennsylvania...

This same area also got completely destroyed by the remnants of tropical storm Lee in 2011. We had a record wet year, then Irene hit 2 weeks before and then Lee's remnants dumped over 10-15 inches right over the same area that Agnes did. It's wild seeing Ida pushing amounts like that. Lee was our 2nd worst flooding event ever

[terstorm1012]

Strange mix of Poorly-built: Completely gone & Well-built/newer: Intact...


Hurricane Agnes rained 18 inches in that same area of Pennsylvania...

This same area also got completely destroyed by the remnants of tropical storm Lee in 2011. We had a record wet year, then Irene hit 2 weeks before and then Lee's remnants dumped over 10-15 inches right over the same area that Agnes did. It's wild seeing Ida pushing amounts like that. Lee was our 2nd worst flooding event ever

I'm in this area. This could be really bad. Lee was the last huge flood of note here and it's been an extremely wet summer here.

[StAuggy]

Not sure how many live up north on the forums but look out for record flooding from Ida. Euro is showing almost a foot of rain right over my house in 2 days...all this falls in the span of 24 hours. this area is drenched from a wet summer, Fred and Henri dumping inches here as well. I already got a foot of rain the past 2 months. This could be one of the worst flooding events for a lot of areas in the mid atlantic and northeast

https://i.imgur.com/PcWbVrI.png

I live in SE PA currently. Def watching this closely. Been seeing mixed outcomes from 3”-4”, 4”-6” and some higher like the one you posted. We don’t need anymore rain!!! This will be very bad if it verifies