ATL: SALLY - Post-Tropical - Discussion

[TallahasseeMan]

Looks like convection is starting to wrap around the center once more, we'll have to see if it can be sustained this time.

[StormPyrate]

I'm just not seeing it. It's still getting sheared quite a bit.

Agree, glad to see it under performing

[us89]

The 12z HWRF run is just like the 06z. Shows some westerly shear affecting the system pretty much all the way until landfall, and the resulting tilted vortex doesn't allow the storm to deepen much beyond 990 mb.

[RL3AO]

Now don't get me wrong. I still think we're looking at a 65 or 70 kt landfall and of course the rain will be the big story as we've talked about now for a few days. I just think the high end chance of a major/near major hurricane has gotten much lower today.

[caneman]

Here in the Tampa Bay area its felt like that June or October sloppy cooler temp type system. Hope it stays that way

[us89]

996 mb extrapolated pressure on the most recent recon pass - about a 1 mb drop from the last pass a little over an hour ago.

[toad strangler]

Now don't get me wrong. I still think we're looking at a 65 or 70 kt landfall and of course the rain will be the big story as we've talked about now for a few days. I just think the high end chance of a major/near major hurricane has gotten much lower today.

Oh wow, all I was reading yesterday was talk of RI and exploding once it splashed off of Florida. What are your thoughts on this not getting to Cat 1?

[wx98]

https://imgur.com/9c8WouP

The LLC is trying to come out from under the covers...

[TallahasseeMan]

I think people should at least wait until tomorrow morning before trying to write this thing off intensity wise. Despite its ugly look it’s continued to deepen today (albeit slowly). I wouldn’t be shocked if things kicked off around DMAX tonight.


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[ConvergenceZone]

Now don't get me wrong. I still think we're looking at a 65 or 70 kt landfall and of course the rain will be the big story as we've talked about now for a few days. I just think the high end chance of a major/near major hurricane has gotten much lower today.

100% agree with you. Not worried about the winds at all with Sally, just the potential of horrible flooding rains. As the weather channel said, the rain is what's going to be the issue withe Sally...

[Shell Mound]

I think the QPF output is going to end up much lower than official estimates indicate. A weaker, less organised Sally would be more likely to move faster as well as track farther east up until landfall. Already the short-term movement has been faster than most of the guidance and the NHC has been forced to “catch up” over time. So a weaker system could also end up reducing the threat of a prolonged stall, since a weaker TC would make landfall much farther east before being “picked up” by the westerlies. I wouldn’t be shocked of QPF totals end up being nearly a foot less than currently indicated. I think landfall is likely to occur somewhere between Pascagoula, MS, and Dauphine Island, AL, as a strong tropical storm or minimal hurricane; recent model runs and other indicators are beginning to favour this outcome.

[TheStormExpert]

Isn’t shear like this in the GoM typical of La Niñas or am I wrong? I remember Irma from three years ago getting sheared as it tracked north up the FL peninsula.

[KimmieLa]

Now don't get me wrong. I still think we're looking at a 65 or 70 kt landfall and of course the rain will be the big story as we've talked about now for a few days. I just think the high end chance of a major/near major hurricane has gotten much lower today.

Oh wow, all I was reading yesterday was talk of RI and exploding once it splashed off of Florida. What are your thoughts on this not getting to Cat 1?

I don't believe it was supposed to strengthen, if any, until early tomorrow morning, per NHC. NHC is saying a CAT 1, so prepare for a CAT 2. My thoughts on whether it will get to CAT 1 is, it might. It has a lot of work to do to get itself together. I can only watch and learn from all on the Board. It amazes me how much has to "line up" for a hurricane to spin up or form. It's a wonder it ever happens! Every year, I learn something new, and I am thankful for everyone. I am pulling for shear and dry air to be victorious, I pray that for every storm!

[TheStormExpert]

Now don't get me wrong. I still think we're looking at a 65 or 70 kt landfall and of course the rain will be the big story as we've talked about now for a few days. I just think the high end chance of a major/near major hurricane has gotten much lower today.

Of course I bet TWC is hyping it up to be a doomsday storm as usual.

Wind still could be an issue, just not the main issue.

[TheAustinMan]

Some climatological perspective may be needed to properly evaluate Sally in the Gulf of Mexico, for both those who may think that "something is off" about Sally's inability to rapidly intensify in peak season, and for those who think that Sally had a substantial shot of getting anywhere near the Category 5 theoretical maximum potential intensity of the northeastern Gulf...

• No hurricane has ever become a major hurricane in the Gulf after hitting Florida as a tropical depression. None.
• No hurricane has ever become a Category 2 hurricane in the Gulf after hitting Florida as a tropical depression. None.
• Only two storms have become Category 1 hurricanes in the Gulf after hitting Florida as a tropical depression. This includes the third storm of 1934 and Hurricane Barry of 1983. The 1934 storm peaked as a 75kt hurricane while Barry reached 70kt, and both became hurricanes on approach to their landfalls on the Texas Coastal Bend and just south of the Rio Grande, respectively.
• Only one tropical cyclone has ever made landfall on Louisiana as a tropical cyclone after hitting Florida as a tropical depression (a depression from 1971).

As a solid 50kt tropical storm already, Sally is within striking distance of being a rather unique storm in the historical record. It is helpful to not extrapolate every convective shift to some portent of boom or bust, not to trust every model output hook, line, and sinker, and to keep a measured take on the system, which begins with the official NHC forecast and then looking at the big picture and thinking about how the pieces interact:

• (Nowcasting) We can tell from satellite imagery that the storm is still facing northwesterly wind shear, as the low-level center has periodically been outside of the main convection throughout the afternoon, and most of the convection is to the southeast, BUT
• (Forecasting) Wind shear may decrease tonight as the storm moves under an upper-level ridge, which combined with warm sea surface temperatures and a moist environment suggest the possibility for convection to increase over the exposed center and for intensification to occur tonight into tomorrow, BUT
• (Forecasting) By tomorrow evening, the southern extension of the polar jet stretching across the Southeastern United States may produce a band of westerly winds over the system, causing an increase in wind shear that may weaken the storm, BUT
• (Thinking About What Might Change) The degree to which that shear weakens Sally is dependent on how organized Sally is and how convectively active it is leading up to that increase in shear. Sometimes (as we saw with Laura in an extreme case), it's a case of too little, too late if the system is producing strong convection, BUT
• (Thinking About Climatology) A storm approaching the northern Gulf coast typically weakens due to entrainment of continental dry air and shallow oceanic heat, and storms similar to Sally have not historically gotten very strong.

Being methodological with how we approach storms gives us a better way to evaluate what Sally is doing by considering the whole soup of ingredients that shape a storm's development one way or another, and not to immediately rush to conclusions for every blip and wobble, and not to assume extremes.

[Craters]

Some climatological perspective may be needed to properly evaluate Sally in the Gulf of Mexico, for both those who may think that "something is off" about Sally's inability to rapidly intensify in peak season, and for those who think that Sally had a substantial shot of getting anywhere near the Category 5 theoretical maximum potential intensity of the northeastern Gulf...

• No hurricane has ever become a major hurricane in the Gulf after hitting Florida as a tropical depression. None.
• No hurricane has ever become a Category 2 hurricane in the Gulf after hitting Florida as a tropical depression. None.
• Only two storms have become Category 1 hurricanes in the Gulf after hitting Florida as a tropical depression. This includes the third storm of 1934 and Hurricane Barry of 1983. The 1934 storm peaked as a 75kt hurricane while Barry reached 70kt, and both became hurricanes on approach to their landfalls on the Texas Coastal Bend and just south of the Rio Grande, respectively.
• Only one tropical cyclone has ever made landfall on Louisiana as a tropical cyclone after hitting Florida as a tropical depression (a depression from 1971).

As a solid 50kt tropical storm already, Sally is within striking distance of being a rather unique storm in the historical record. It is helpful to not extrapolate every convective shift to some portent of boom or bust, not to trust every model output hook, line, and sinker, and to keep a measured take on the system, which begins with the official NHC forecast and then looking at the big picture and thinking about how the pieces interact:

• (Nowcasting) We can tell from satellite imagery that the storm is still facing northwesterly wind shear, as the low-level center has periodically been outside of the main convection throughout the afternoon, and most of the convection is to the southeast, BUT
• (Forecasting) Wind shear may decrease tonight as the storm moves under an upper-level ridge, which combined with warm sea surface temperatures and a moist environment suggest the possibility for convection to increase over the exposed center and for intensification to occur tonight into tomorrow, BUT
• (Forecasting) By tomorrow evening, the southern extension of the polar jet stretching across the Southeastern United States may produce a band of westerly winds over the system, causing an increase in wind shear that may weaken the storm, BUT
• (Thinking About What Might Change) The degree to which that shear weakens Sally is dependent on how organized Sally is and how convectively active it is leading up to that increase in shear. Sometimes (as we saw with Laura in an extreme case), it's a case of too little, too late if the system is producing strong convection, BUT
• (Thinking About Climatology) A storm approaching the northern Gulf coast typically weakens due to entrainment of continental dry air and shallow oceanic heat, and storms similar to Sally have not historically gotten very strong.

Being methodological with how we approach storms gives us a better way to evaluate what Sally is doing by considering the whole soup of ingredients that shape a storm's development one way or another, and not to immediately rush to conclusions for every blip and wobble, and not to assume extremes.

I wish I could give this one about 50 likes. Excellent post, AustinMan.

The only questionable thing is your being in Austin, not Ithaca, in the summer. Ain't that bassackwards?...

[Sanibel]

Apparently the conditions were not as good as expected...As Wx57 said, this is a seriously challenged system struggling to form...

Atlantic conditions could be becoming negative...

Flood is still not covering the driveway so we are not at maximum and it appears to be leveling-off...

[edu2703]

Yesterday, I said that I didn't expect any significant strengthening before tonight. At least I got it partially right. Now I wonder if we are going to see any significant strengthening from Sally.

Honestly, I expected to see a better looking storm than it is right now. I believed it would be a solid Cat 3 hurricane at her peak. Now, I would be surprised if Sally reaches Cat 2. It will be a significant rainfall event regardless of max wind speed. It's important to make this clear.

[Steve]

Apparently the conditions were not as good as expected...As Wx57 said, this is a seriously challenged system struggling to form...

Atlantic conditions could be becoming negative...

Flood is still not covering the driveway so we are not at maximum and it appears to be leveling-off...

Climatology vs MJO?

[Steve]

Right now we have east winds 10-15 and gusting. It’s hot outside -88/89. Humidity is >60%. Pressure is pretty high here at 1012 so that’s something to watch for everyone in the strike zone. You can tell the weather is changing and the tropics are coming up.