ATL: IDA - Remnants - Discussion

[wx98]

it's warmer out there in the loop current compared to 16 year ago.
https://i.imgur.com/bG3vLuT.gif

The color scale is off on that map making it appear the entire basin has way more OHC than 2005.

[ScottNAtlanta]

Woops, thanks to everyone who corrected. So 100 MPH is expected by 1PM central, 2PM eastern by the 4AM central discussion.

Actually 12 hrs from 4am Central would be 4pm Central...it's ok, it is horribly confusing for the best of people. Just think of when NHC puts out their advisories...11am/pm 5am/pm (eastern)

Yes but they don’t do it for 12 hours from advisory time. They do it for 12 hours from the previous best track time (three hours earlier). So the 12 hour forecast is really 9 hours from advisory time.

See! Like I said, confusing for the best of us!

I hereby give wx98 the daily time interpretation award

[KWT]

It’s looking good now, but since we haven’t seen a Rita-like explosion in intensity, I’m revising my peak estimate to 110mph.

Just kidding, but really though, if the NHC varied it’s forecast as much as some of us are over these micro-trends, no one would ever take them seriously.

Yeah I think the NHC estimate looks in the ballpark, probably somewhere between 120-130kts seems the most reasonable unless we luck out and we get the start of a EWRC (before it has a chance to really broaden out the field more.)

Given the huge heat content laying ahead over the next 24hrs and what is pretty good conditions aloft (maybe not perfect, but still good enough) its hard to not see anything but RI/EI happening.

[SEASON_CANCELED]

I maybe late in asking this but why havent evacuations been issued?

To me this is looking like a katrina 2 type scenario with levees failing...or is something different?

I just dont wanna wake and see them do emergency evacuations 6 hours before the storm like last time

Evacuations have been issued for areas prone to surge...there's a separate thread for posting them.

Thanks

Good to see our elected officials doing the right thing now instead of waiting. Guess ill go find that thread

[hohnywx]

[skyline385]

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

5KT decrease from last advisory

[wx98]

I maybe late in asking this but why havent evacuations been issued?

To me this is looking like a katrina 2 type scenario with levees failing...or is something different?

I just dont wanna wake and see them do emergency evacuations 6 hiurs before the storm like last time

The mayor of New Orleans said Friday evening they didn’t have time for mandatory evacuation.

[KWT]

it's warmer out there in the loop current compared to 16 year ago.
https://i.imgur.com/bG3vLuT.gif

The color scale is off on that map making it appear the entire basin has way more OHC than 2005.

Yes, though the point still stands that the loop current is warmer than it was in 2005 and we all know the troubles caused by that in 2005. That is some very impressive OHC!

[wwizard]

Securing potential debris so pardon me for short messages, but St. Charles Parish (west of NO) at least is under mandatory evac which may explain some traffic observed as well.

I'm hearing that gas stations are dry all over the region, it that's they case hopefully people stuck in traffic don't run out of it.

After the Rita situation in Houston, I think the general consensus is that these kind of mass evacuations hurt more than they help. Evacuating a small town is one thing. But evacuating a million person metro is bound to leave alot of people more vulnerable than they might have been had they stayed in their neighborhood and went to the local gym or other sturdy structure.

The thing most people don't understand is that evacuation should be reserved mostly for those at risk of storm surge. In Rita, for example, people in West U, Spring, Jersey Village, The Heights, etc, did not need to evacuate. That should have just been for the coastal communities, Galveston Island and those along the Bay, Texas City, League City, etc. But because Katrina happened just a few weeks earlier, the panic was on.

I realize NOLA is a different situation and setup so the Houston example doesn't really apply. And as someone mentioned up thread, even if contraflow had been implemented, the nightmare awaiting at the end of the line is insane, but at least that's much further away from the imminent danger you would have been in not leaving when you probably should have.

This is why waiting til the last minute for something like this is never a good idea. I get the procrastinators, I can be one myself on occasion, but for something like this, supplies, gas, go quickly, and if you wait, you get left without, or stuck in the worst traffic of your life.

There's a reason we have a hurricane "season". Just like sports prepare beforehand for their seasons, people in hurricane country should always be preparing before the hurricane season starts. But for whatever reason most wait until it's too late.

[ElectricStorm]

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

5KT decrease from last advisory

It is however the second 115kt point is inland and the point over water is still a ways off from the coast so it's basically the same as the last few advisories

[StormPyrate]

I maybe late in asking this but why havent evacuations been issued?

To me this is looking like a katrina 2 type scenario with levees failing...or is something different?

I just dont wanna wake and see them do emergency evacuations 6 hiurs before the storm like last time

New Orleans did not evacuate for Katrina until too late, as I understand it, there are legal ramifications to doing so that no one in New Orleans leadership ever seems to want to own

[tolakram]

The fixed timepoints confuse people every year, and I think the NHC should make it a point to highlight critical times rather than sticking to the fixed points, but that's just my opinion.

000
WTNT44 KNHC 281457
TCDAT4

Hurricane Ida Discussion Number 9
NWS National Hurricane Center Miami FL AL092021
1000 AM CDT Sat Aug 28 2021

The satellite presentation of Ida has continued to improve this
morning with the center embedded within a fairly symmetric Central
Dense Overcast and hints of the eye in both visible in infrared
satellite imagery. Earlier microwave imagery revealed a well-
defined low- to mid-level eye and excellent spiral banding over the
northern semicircle. Both NOAA and Air Force Reserve hurricane
hunter aircraft, somewhat surprisingly, have not found a
significantly deepening tropical cyclone yet, but given the very
recent increase in organization and structure, the winds are likely
to catch up to the satellite appearance very soon. Using the latest
flight-level and SFMR wind data from the aircraft and satellite
intensity estimates the initial wind speed remains 75 kt for this
advisory. The aircraft data does indicate that Ida's wind field has
expanded, and the NHC wind radii have been adjusted accordingly.

Given the improved inner-core structure Ida appears poised to
rapidly intensify during the next 12 to 24 hours as it remains
within a favorable environment of low vertical wind shear and over
warm water. Although the interpolated intensity guidance has
lowered somewhat due to the fact that Ida has not significantly
strengthened yet, the explicit forecasts from the dynamical models
continue to support significant deepening, and the latest runs of
the HWRF and HMON models indicate Ida will reach Category 4 strength
before landfall. The new NHC intensity forecast calls for rapid
intensification to Category 4 strength during the next 24 hours.
After that time, fluctuations in intensity are possible due to
eyewall replacement cycles as Ida approaches the northern Gulf
coast. After landfall, rapid weakening is expected and Ida is
forecast to weaken to a tropical depression by Monday night, and
become a post-tropical cyclone as it moves over the Tennessee Valley
by mid-week.

Ida has been moving steadily northwestward or 315/14 kt. A deep
layer ridge near the southeastern United States coast is forecast to
shift westward during the next day or so, and this should continue
to steer Ida northwestward through landfall on Sunday. The track
guidance remains in remarkably good agreement through 36 hours, and
the new NHC track forecast is essentially unchanged during that
time, and continues to indicate that Ida will reach the coast of
Louisiana on Sunday. After landfall, Ida will be near the western
extent of the ridge and should turn northward and then northeastward
as it recurves into the southern portion of the mid-latitude
westerlies. The track guidance has shifted slightly westward beyond
48 hours, and the track forecast over the southern U.S. and the
Tennessee Valley has been adjusted accordingly. Users are again
reminded to not focus on the exact details of the track forecast as
storm surge, wind, and rainfall impacts will extend far from the
center. Wind and rainfall impacts will also penetrate inland
through early next week after Ida makes landfall.

Key Messages:

1. There is a danger of life-threatening storm surge inundation
Sunday along the coasts of Louisiana and Mississippi within the
Storm Surge Warning area. Extremely life-threatening inundation of
9 feet or greater above ground level is possible somewhere within
the area from Morgan City, Louisiana, to the coast of Mississippi.
Overtopping of local levees outside of the Hurricane and Storm
Damage Risk Reduction System is possible where local inundation
values may be higher. Interests throughout the warning area should
follow any advice given by local officials.

2. Ida is expected to be an extremely dangerous major hurricane when
it reaches the coast of Louisiana. Hurricane-force winds are
expected Sunday in portions of the Hurricane Warning area along the
Louisiana coast, including metropolitan New Orleans, with
potentially catastrophic wind damage possible where the core of Ida
moves onshore. Actions to protect life and property should be rushed
to completion today in the warning area.

3. Ida is likely to produce heavy rainfall Sunday and Monday across
the central Gulf Coast from southeast Louisiana to coastal
Mississippi, resulting in life-threatening flash and urban flooding
and significant river flooding impacts. As Ida moves inland,
significant flooding impacts are likely across portions of the Lower
Mississippi and Tennessee Valleys Monday and Tuesday.

FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

$$
Forecaster Brown

[skyline385]

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

5KT decrease from last advisory

It it however the second 115kt point is inland and the point over water is still a ways off from the coast so it's basically the same as the last few advisories

Good point, did not catch that so there is still potential for 120 KT

[cycloneye]

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

5KT decrease from last advisory

They will get the same effects so those there who see this little drop, dont be fooled.

[Kohlecane]

judging by the Recon fixes and IR overlay it has definitely jumped more N the last 2 hours. Also I'm not sure if Recon is staying, looked like they were headed back to the center then turned, when is the next flight take off?

[KWT]

5KT decrease from last advisory

It it however the second 115kt point is inland and the point over water is still a ways off from the coast so it's basically the same as the last few advisories

Good point, did not catch that so there is still potential for 120 KT

Also from reading the discussion sounds like they don't want to explicitly go above 115kts yet as they can't be sure there won't be internal changes such as EWRC, etc.

Should this system really take off, especially tonight they will probably quickly uplift that expectation.

Regardless this will be a dangerous hurricane.

[ScottNAtlanta]

judging by the Recon fixes and IR overlay it has definitely jumped more N the last 2 hours. Also I'm not sure if Recon is staying, looked like they were headed back to the center then turned, when is the next flight take off?

They just sent a plane out to Nora so I dont know when the next plane will go out to Ida

[tolakram]

Harvey loop during intensification, just for some comparison.

[youtube]https://youtu.be/4t7tj8XnKSQ[/youtube]

IDA visible loop: https://whirlwind.aos.wisc.edu/~wxp/goes16/grb/meso_vis/meso1_60.html

[skyline385]

INIT 28/1500Z 24.8N 86.1W 75 KT 85 MPH
12H 29/0000Z 26.3N 87.9W 100 KT 115 MPH
24H 29/1200Z 28.0N 89.8W 115 KT 130 MPH
36H 30/0000Z 29.4N 91.0W 115 KT 130 MPH...INLAND
48H 30/1200Z 31.0N 91.5W 60 KT 70 MPH...INLAND
60H 31/0000Z 32.7N 91.0W 30 KT 35 MPH...INLAND
72H 31/1200Z 34.4N 89.8W 25 KT 30 MPH...INLAND
96H 01/1200Z 36.8N 85.3W 20 KT 25 MPH...POST-TROP/INLAND
120H 02/1200Z 37.9N 79.9W 20 KT 25 MPH...POST-TROP/INLAND

5KT decrease from last advisory

They will get the same effects so those there who see this little drop, dont be fooled.

Well yea, I thought everyone knows that and I never meant to suggest otherwise. Hope my comment didnt come off like that, if it did it wasnt my intention...

[kevin]

I know it's easy to say when recon is leaving, but it really looks like Ida is taking off right now. After the unexpected high central pressure, at least to me (I guess I was expecting low 970s instead of 980s), I feel reluctant to make any new bets but it's bound to deepen at some point so I still think the next recon will find a significantly stronger storm.