ATL: HARVEY - Post-Tropical - Discussion

[MaineWeatherNut]

Well an hour later and the eyewall has degraded... Guess this is to be expected with all that green confined around the core.

I think what we are seeing is the first of many EWRC, whenever this new eye clears out, I will not be shocked to see a stadium eye where the bottom is about 15 miles wide and the top is about 60 miles wide.

Don't think it's EWRC. Don't think there was a completed closed eyewall in the first place.

Didn't the last several VDMs from the last AF recon flight say closed Eyewall?

[CrazyC83]

Once we get into DMAX later this evening, that will likely tell the eventual tale. I'd think peak will be around this time tomorrow, with some weakening before landfall (but still very dangerous!)

[1900hurricane]

The recent Brownsville soundings have had an EL a little above 150 mb and a little colder than -75ºC. Thus far, the could tops haven't been quite making it there up to this point, but we'll see if that changes starting with this convective burst.

[tolakram]

I have a question that I hope someone can answer:

In the Jeff L. upadates, he references the storm surge numbers are being measured "above the ground". Does anyone know where he might be getting these "above the ground" numbers? My understanding has always been that storm surge was measured as the height of the water above the normal predicted astronomical tide.

The information he has posted is extremely frightening.

Above ground means above local ground level. It takes into account tides and such to produce expected numbers at the time of the surge. Above normal water level is confusing as you need to know what the tide is to calculate just how high water will get.

[KWT]

Indeed SDF, I've been waiting for the next real large burst, its taken a little longer than I had expected but given we are now heading into the overnight hours and the fact this area is pumping large amounts of lightning out, I'm feeling confident recon might have a bumpy time once it makes it round there, I'm not sure the winds will have really reacted (though western quadrant may have some tasty gusts!) but I'll be waiting to see the pressure drop like a stone over the course of the recon's flight.

PS, its got a closed wall, its just never really developed a complete and intense convective eyewall, its always had little patchy parts which are closed but weaker than the rest.

[Kingarabian]

I think what we are seeing is the first of many EWRC, whenever this new eye clears out, I will not be shocked to see a stadium eye where the bottom is about 15 miles wide and the top is about 60 miles wide.

Don't think it's EWRC. Don't think there was a completed closed eyewall in the first place.

Didn't the last several VDMs from the last AF recon flight say closed Eyewall?

Last VDM posted on the recon thread:

L. OPEN WSW

[RL3AO]

I have a question that I hope someone can answer:

In the Jeff L. upadates, he references the storm surge numbers are being measured "above the ground". Does anyone know where he might be getting these "above the ground" numbers? My understanding has always been that storm surge was measured as the height of the water above the normal predicted astronomical tide.

The information he has posted is extremely frightening.

All storm surge values from the Hurricane Center are referenced to above ground. This was changed to make the communication easier since most people don't know how far above sea level they live, much less High astronomical tide

[ronyan]

eyewall was noted as closed previous to that.

[Kingarabian]

:uarrow: eyewall was noted as closed previous to that.

Guess it was a fairly weak eyewall then since it opened back up and has remained open ever since (@850mb).

[ronyan]

:uarrow: eyewall was noted as closed previous to that.

Guess it was a fairly weak eyewall then since it opened back up and has remained open ever since.

Yes it was apparently disrupted.

[psyclone]

I have a question that I hope someone can answer:

In the Jeff L. upadates, he references the storm surge numbers are being measured "above the ground". Does anyone know where he might be getting these "above the ground" numbers? My understanding has always been that storm surge was measured as the height of the water above the normal predicted astronomical tide.

The information he has posted is extremely frightening.

Above ground means above local ground level. It takes into account tides and such to produce expected numbers at the time of the surge. Above normal water level is confusing as you need to know what the tide is to calculate just how high water will get.

In addition, the NHC's storm surge products are presented as ground level inundation in order to better communicate the hazard. These are fantastic resources and I highly encourage people to access this info

[Frank P]

I have a question that I hope someone can answer:

In the Jeff L. upadates, he references the storm surge numbers are being measured "above the ground". Does anyone know where he might be getting these "above the ground" numbers? My understanding has always been that storm surge was measured as the height of the water above the normal predicted astronomical tide.

The information he has posted is extremely frightening.

Above ground means above local ground level. It takes into account tides and such to produce expected numbers at the time of the surge. Above normal water level is confusing as you need to know what the tide is to calculate just how high water will get.

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..

[curtadams]

Where did that dry air come from?

You can see a weak zone spiraling in from the south, up a slot in the east side, and then sometimes a little north of the eye. It's being drawn in from Mexico and spiraling around the core as it goes in. The air will be quite dry as it's continental air *and* it's coming off high mountains.

[Aric Dunn]

:uarrow: eyewall was noted as closed previous to that.

Guess it was a fairly weak eyewall then since it opened back up and has remained open ever since (@850mb).

radar is showing closed.. even though the east quad is just coming into radar range the fact that you can see means it reaching high up thus well established..

[snoop9928]

Anyone have a link showing wind speeds? I know houston is going to get hammered with rain, but trying to see how bad the wind will be with it.

[AubreyStorm]

Another look!

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

[Frank P]

For example, the sea wall in Biloxi is about 10 feet above sea level.. if I get a storm surge of 10 feet at nominal tide, water will be at the top of the sea wall.. additionally you must factor in the waves as well.. in Biloxi we usually get small 2-4 waves during storms due to our very shallow continental shelf along the MS coastal waters, and that by itself gives us a very high storm surge multiplier, which makes our surges so dang high even in minimum storms...

[Kingarabian]

Recon almost there.

[Blinhart]

Anyone have a link showing wind speeds? I know houston is going to get hammered with rain, but trying to see how bad the wind will be with it.

There is no way of actually knowing how strong the wind is going to get, there is extrapolations of the possibilities of the strength of winds, but no matter what the least you will get is TS strength but I say there is a slight chance of Hurricane strength winds, but the timing is very fluid at the moment.

[jasons2k]

For example, the sea wall in Biloxi is about 10 feet above sea level.. if I get a storm surge of 10 feet at nominal tide, water will be at the top of the sea wall.. additionally you must factor in the waves as well.. in Biloxi we usually get small 2-4 waves during storms due to our very shallow continental shelf along the MS coastal waters, and that by itself gives us a very high storm surge multiplier, which makes our surges so dang high even in minimum storms...

It was changed this year to mean 'above ground level' so that those factors no longer need to be taken into consideration.