ATL: IDA - Remnants - Discussion

[Shell Mound]

https://imagizer.imageshack.com/img924/650/I2DFdX.gif

Dual outflow channels are setting up as Ida nears W Cuba between two ULLs on WV.

[weeniepatrol]

FWIW this site https://www.visitcaymanislands.com/en-us/about-cayman/weather is reporting 1002.7mb at the capital of the Cayman Islands

[Extratropical94]

FWIW this site https://www.visitcaymanislands.com/en-us/about-cayman/weather is reporting 1002.7mb at the capital of the Cayman Islands

Sounds reasonable. Owen Roberts International Airport on Grand Cayman reported 1003 mb at 08Z

MWCR 270800Z 32008KT 290V350 9999 -SHRA BKN010 26/25 Q1003

[beoumont]

Dual outflow channels are setting up as Ida nears W Cuba between two ULLs on WV.

Sometimes affectionately and quite simply known as an UPPER HIGH.

[weeniepatrol]

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 20.0N 81.4W 40 KT 45 MPH
12H 27/1800Z 21.5N 82.9W 50 KT 60 MPH...OVER ISLE OF YOUTH
24H 28/0600Z 23.4N 84.9W 60 KT 70 MPH
36H 28/1800Z 25.3N 86.9W 70 KT 80 MPH
48H 29/0600Z 27.1N 88.8W 85 KT 100 MPH
60H 29/1800Z 28.7N 90.2W 100 KT 115 MPH
72H 30/0600Z 30.1N 91.1W 85 KT 100 MPH...INLAND
96H 31/0600Z 33.0N 90.5W 35 KT 40 MPH...INLAND
120H 01/0600Z 35.0N 88.0W 25 KT 30 MPH...INLAND

$$
Forecaster Beven

[Blinhart]

We don't know what type of Weather Radar the Cayman Islands have, don't know how well they are when looking at storms over the Caribbean Sea. So you can't always trust radar. Can't wait until RECON can get in there so there are not as many questions about where this storm is. I have to agree though with some who think that this system looks to be sheared a little, but that should subside by the time RECON gets in there and by the time they are done they should be finding a system strengthening.

[Blinhart]

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 20.0N 81.4W 40 KT 45 MPH
12H 27/1800Z 21.5N 82.9W 50 KT 60 MPH...OVER ISLE OF YOUTH
24H 28/0600Z 23.4N 84.9W 60 KT 70 MPH
36H 28/1800Z 25.3N 86.9W 70 KT 80 MPH
48H 29/0600Z 27.1N 88.8W 85 KT 100 MPH
60H 29/1800Z 28.7N 90.2W 100 KT 115 MPH
72H 30/0600Z 30.1N 91.1W 85 KT 100 MPH...INLAND
96H 31/0600Z 33.0N 90.5W 35 KT 40 MPH...INLAND
120H 01/0600Z 35.0N 88.0W 25 KT 30 MPH...INLAND

$$
Forecaster Beven

We got our M now

[Chemmers]

How predicting a major at landfall off 115 mph, I think unfortunately they will keep adding on 5mph to for forecast at landfall, very interested to see what the recon finds

[kevin]

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 20.0N 81.4W 40 KT 45 MPH
12H 27/1800Z 21.5N 82.9W 50 KT 60 MPH...OVER ISLE OF YOUTH
24H 28/0600Z 23.4N 84.9W 60 KT 70 MPH
36H 28/1800Z 25.3N 86.9W 70 KT 80 MPH
48H 29/0600Z 27.1N 88.8W 85 KT 100 MPH
60H 29/1800Z 28.7N 90.2W 100 KT 115 MPH
72H 30/0600Z 30.1N 91.1W 85 KT 100 MPH...INLAND
96H 31/0600Z 33.0N 90.5W 35 KT 40 MPH...INLAND
120H 01/0600Z 35.0N 88.0W 25 KT 30 MPH...INLAND

$$
Forecaster Beven

We got our M now

Here's the associated graphic. According to NHC Ida will have roughly 30 - 35 hours before landfall after reaching hurricane strength.

[Blinhart]

This course is very dangerous because it moves just slightly more W than the predicted NW angle, will add hours and much more storm surge. The more time this storm has over water has time to have this surge build up under the CDO and also more time for the RI. If the storm comes in just 20 or so miles further West it will have additional time over water not just because of the Gulf but also Vermillion Bay, very dangerous set up.

[Stormgodess]

yeh they are finally all reporting she is gonna be a Cat 3 at land fall

[Shell Mound]

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 20.0N 81.4W 40 KT 45 MPH
12H 27/1800Z 21.5N 82.9W 50 KT 60 MPH...OVER ISLE OF YOUTH
24H 28/0600Z 23.4N 84.9W 60 KT 70 MPH
36H 28/1800Z 25.3N 86.9W 70 KT 80 MPH
48H 29/0600Z 27.1N 88.8W 85 KT 100 MPH
60H 29/1800Z 28.7N 90.2W 100 KT 115 MPH
72H 30/0600Z 30.1N 91.1W 85 KT 100 MPH...INLAND
96H 31/0600Z 33.0N 90.5W 35 KT 40 MPH...INLAND
120H 01/0600Z 35.0N 88.0W 25 KT 30 MPH...INLAND

$$
Forecaster Beven

We got our M now

Here's the associated graphic. According to NHC Ida will have roughly 30 - 35 hours before landfall after reaching hurricane strength.

https://i.imgur.com/9RVv4di.png

Fortunately, it doesn't begin to slow down until past the Loop Current (highest TCHP). Based on the positions Ida looks to have about 30h as a hurricane while over water, little more than half of which should be over the Loop Current. The forward speed decelerates as soon as Ida begins to leave the highest TCHP south of LA. Besides the possibility of shear from Nora, Ida's relatively brief stay over the Loop Current may be the primary limitation insofar as maximum potential intensity is concerned. However, the angle of approach and slowdown during landfall will certainly maximise rain and surge.

[Shell Mound]

 https://twitter.com/WxBrenn/status/1431187246829510658



 https://twitter.com/KathrynProciv/status/1431193208424443904




This probably deserves a

[kevin]

I seem to be the 'database person' the last few days, so here's another one. An overview of the fastest RI in the GOM in August. Only includes cases where winds increased by at least 30 kts within 24 hrs, as is the official definition by the NHC. Therefore, the list is sorted by the increase in windspeed, not the fastest pressure drop. Only intensification while in the GOM is included. The absolute records are by Celia and the Freeport hurricane, which both managed to intensify by 70 kts within 24 hours in the August GOM before both making landfall in Texas.

Year / Storm / Wind speed increase in 24 hours (kt) / Pressure drop in 24 hours (mb) / Category increase in 24 hours

1970 / Celia / 70 / 42 / TD to cat 3
1932 / Freeport / 70 / ?? / TS to cat 4
1977 / Anita / 65 / 46 / cat 2 to cat 5
1969 / Camille / 60 / 61 / cat 2 to cat 5
2020 / Laura / 55 / 45 / cat 1 to cat 4
2005 / Katrina / 50 / 42 / cat 3 to cat 5
1999 / Bret / 50 / 30 / cat 1 to cat 4
1918 / Unnamed / 40 / ?? / TS to cat 3
1886 / Unnamed / 40 / ?? / cat 2 to cat 4
1880 / Unnamed / 40 / ?? / cat 1 to cat 4
1856 / Unnamed / 40 / ?? / cat 1 to cat 4
2004 / Charley / 35 / 33 / cat 2 to cat 4
2020 / Harvey / 35 / 32 / cat 1 to cat 4
1975 / Caroline / 35 / 27 / cat 1 to cat 3
1983 / Alicia / 30 / 24 / cat 1 to cat 3
1945 / Unnamed / 30 / ?? / TS to cat 2
1942 / Unnamed / 30 / ?? / cat 1 to cat 3
1879 / Unnamed / 30 / ?? / TS to cat 1

[Shell Mound]

 https://twitter.com/MichaelRLowry/status/1431084475987943424

[Nimbus]

Most of us expected Ida to be projected as a major hurricane and even though 5 or 10 knots of additional strength in the eyewall often doesn't make much difference, the forecast slowdown and larger storm depicted in the 06z runs is concerning. The light shear persisting is good news for Cuba although it was depicted in most of the model runs yesterday so no surprise there either. They don't usually fly the G-IV upper air analysis flights till late in the forecast when the greater data density is subject to less random evolution. They narrowed the landfall cone a little bit but clearly if you are below 5 ft elevation in LA the shutters are up, you are packed and ready to bug out.

[Kohlecane]

One thing is for sure This has really pulsed over the last 8 hours, and IMO looks to have been moving along the far E component of the NHC cone obviously some dynamics will change this "hopefully" but it is interesting that models shifted ever so slightly Westward. Good thing Recon will get there before Cuba
https://weather.cod.edu/satrad/?parms=r ... =undefined

[Kohlecane]

And going back through the posts agree with the envelope of this structure and the effects on a lot of places not just LF location, as someone stated previously Cat 3 Katrina vs Cat 5 Andrew

[Blinhart]

Most of us expected Ida to be projected as a major hurricane and even though 5 or 10 knots of additional strength in the eyewall often doesn't make much difference, the forecast slowdown and larger storm depicted in the 06z runs is concerning. The light shear persisting is good news for Cuba although it was depicted in most of the model runs yesterday so no surprise there either. They don't usually fly the G-IV upper air analysis flights till late in the forecast when the greater data density is subject to less random evolution. They narrowed the landfall cone a little bit but clearly if you are below 5 ft elevation in LA the shutters are up, you are packed and ready to bug out.

Yep, I'm at 20 feet so I'm waiting a little longer, not expecting to leave until Saturday if at all.

[aspen]

What’s up with the NOAA plane? It hasn’t transmitted in two hours.