ATL: HARVEY - Post-Tropical - Discussion

[RL3AO]

My understanding is that if they say you are going to get a 10 foot storm surge, it is 10 above sea level... you also have to factor in the tidal ranges as well.. a storm surge during low tide is much better than at high tide..

Not anymore. Everything is referenced to inundation (above ground level). The storm surge inundation map accounts for tidal ranges in the ensemble.



Everything on this map is above ground level. Where there is red, that means at least a 10% chance that the first floor of your house will be underwater.

[Frank P]

It was changed this year to mean 'above ground level' so that those factors no longer need to be taken into consideration.[/quote]
Thanks, best I go and read up about it...

[txwatcher91]

Massive hot towers firing all around now, eye being obscured and CDO forming a nice circular shape. This is the final step before we see intense pressure drops and wind spiking fast. I expect this will be a category 4 by morning and peak near 160mph, 915mb pressure.

915MB 160mph? got a ways to go before that is a possibility...I am thinking high end cat3

Yes, we have a perfect combo of conditions for it to do that tonight. You have DMAX, highest TCHP ahead, a solid CDO forming now, and the core seems to really be heating up. Next step will be to see the eye suddenly clear out and a nice ring of red all around on IR. From there, I would expect very rapid pressure drops. I’m thinking of Rita and Wilma rapid pressure drops (but not as strong).

[hd44]

http://tropic.ssec.wisc.edu/real-time/adt/odt09L.html Raw t

[Frank P]

Ok, so does that mean a surge above ground level at 10 feet would still be above sea level with the tide already factored in... and does that include wave action as well... please advise

[CrazyC83]

Ok, so does that mean a surge above ground level at 10 feet would still be above sea level with the tide already factored in... and does that include wave action as well... please advise

Tides aren't very significant along most of the Gulf coast, adding (or subtracting) less than a foot typically. It will be bad no matter when it comes in.

[KWT]

http://tropic.ssec.wisc.edu/real-time/adt/odt09L.html Raw t

Not surprised that has shot up given the big burst of convection that has gone up in the last 90 mins. Raw numbers would suggest a major hurricane right now but I'm not convinced the winds will have quite caught up yet.

Anyway recon is nearly there!!

[Kingarabian]

Massive hot towers firing all around now, eye being obscured and CDO forming a nice circular shape. This is the final step before we see intense pressure drops and wind spiking fast. I expect this will be a category 4 by morning and peak near 160mph, 915mb pressure.

915MB 160mph? got a ways to go before that is a possibility...I am thinking high end cat3

Yes, we have a perfect combo of conditions for it to do that tonight. You have DMAX, highest TCHP ahead, a solid CDO forming now, and the core seems to really be heating up. Next step will be to see the eye suddenly clear out and a nice ring of red all around on IR. From there, I would expect very rapid pressure drops. I’m thinking of Rita and Wilma rapid pressure drops (but not as strong).

The coldest tops over the CDO have disconnected now compared to the past couple of hours. Typically in a major hurricane, those tops are round and connected with an eye feature in the middle.

[jasons2k]

Ok, so does that mean a surge above ground level at 10 feet would still be above sea level with the tide already factored in... and does that include wave action as well... please advise

Yes, the tide is factored in but wave action is not.

[RL3AO]

Ok, so does that mean a surge above ground level at 10 feet would still be above sea level with the tide already factored in... and does that include wave action as well... please advise

Suppose your house is 10 feet above sea level. The storm surge/storm tide is 15 feet above sea level. That means your house would experience 5 feet of water above ground level. The 5 feet is what the NHC and the maps are showing you*.

However, it does not account for waves.

* When the advisory says 6 to 12 feet they mean 6 to 12 feet above ground level near the coast. The storm surge inundation graphic isn't showing the expected amount of water above ground level, but a reasonable worst case scenario.

[MaineWeatherNut]

915MB 160mph? got a ways to go before that is a possibility...I am thinking high end cat3

Yes, we have a perfect combo of conditions for it to do that tonight. You have DMAX, highest TCHP ahead, a solid CDO forming now, and the core seems to really be heating up. Next step will be to see the eye suddenly clear out and a nice ring of red all around on IR. From there, I would expect very rapid pressure drops. I’m thinking of Rita and Wilma rapid pressure drops (but not as strong).

The coldest tops over the CDO have disconnected now compared to the past couple of hours. Typically in a major hurricane, those tops are round and connected with an eye feature in the middle.

Recon is nearly there then we can find out for sure...

[Frank P]

got it thanks, but I think I like the old way better since I have been using it for 45 years...

[hohnywx]

Another look!

Vía Twitter:
I-37 heading out of Corpus. Looks busy from above. #Harvey2017

[img]removed[/img]

Good thing to see...means people are taking the storm seriously!

[Kingarabian]

Yes, we have a perfect combo of conditions for it to do that tonight. You have DMAX, highest TCHP ahead, a solid CDO forming now, and the core seems to really be heating up. Next step will be to see the eye suddenly clear out and a nice ring of red all around on IR. From there, I would expect very rapid pressure drops. I’m thinking of Rita and Wilma rapid pressure drops (but not as strong).

The coldest tops over the CDO have disconnected now compared to the past couple of hours. Typically in a major hurricane, those tops are round and connected with an eye feature in the middle.

[img]http://i.imgur.com/ymmhk5U.gif[img]

Recon is nearly there then we can find out for sure...

I'm going to say 85-90kt winds and maybe a pressure of 969.

[Cunxi Huang]

Dvorak estimates:
DT=4.5 based on CNTR embedded in LG.

[MGC]

The waves and water movement in the velocity zone is what destroys structures. After Katrina there was a pile of debris a good 15 feet high where the water had pushed the remains of houses and people. Only concrete structures survived the surge in Katrina.

Does look like a bit of dry air was ingested by Harvey a bit ago.....MGC

[RL3AO]

That's some impressive convection. Wouldn't be surprised to see that kick off another intensification trend as it wraps around the eye.

[Nederlander]

That's some impressive convection. Wouldn't be surprised to see that kick off another intensification trend as it wraps around the eye.

Is that recent blow-up due to Harvey tapping into that warm current eddy that has been discussed?

[1900hurricane]

I usually use my blog to post on the WPac, but for those interested, I just completed an entry for Hurricane Harvey.

North Atlantic Tropical Analysis: August 24, 2017 - Harvey Special

[Aric Dunn]

Radar is starting become more ominous.. pretty solid eyewall now and showing some deeper convection increasing around it.