ATL: ISAAC - Post-Tropical - Discussion

[deltadog03]

GFDL and HWRF both shifted East by a good bit. Looks like the threat to my area is decreasing but at least it seems like most have prepared like they should in case things change.

I just saw the hwrf, where did the GFDL go?

Pretty much directly over the NHC track.

http://www.sfwmd.gov/portal/page/portal/xweb%20weather/hurricane%20model%20plots

Thank You!

[SouthDadeFish]

Microwave imagery shows Isaac was becoming much better organized:

37 GHz Color:



85 GHz Color:



But then dry air partially disrupted the core:

[WeatherGuesser]

it needs to intensify tonight if it plans on making it to a hurricane at all.....

Less intense is better.

[MGC]

Isaac is moving to the NW at 10mph and is expected to slow.....this will allow the storm more time over the warm waters of the GOM.....plenty of time to shake out the dry air. The comparisons to Katrina are an insult.....MGC

The above is the opinion of MGC and not an official forecast.

[monicaei]

And profoundly offensive... How quickly people forget what K really was.

Doesn't take a meteorology degree to figure out this isn't gonna kill a couple thousand people, cripple a major metropolitan area and profoundly change the landscape of an entire state.

Never forget, huh?

Bold statement considering this storm is still well offshore. Not picking at you, same was said 4/26/11 in my area. The next day we had a huge tornado outbreak killing hundreds, wiping two cities off the map, Pleasant grove and phil cambell.

Sorry for going off topic.

I'll eat my words if Isaac goes Katrina. I'll also be salvaging a lot of stuff and trying to figure out how to communicate with family and friends, so give me a few weeks. Then I'll eat my words.

It's a bold statement, but certainly less bold than predicting it will rival katrina.

[bella_may]

This is from Dr. Neil Frank, former NHC director and someone that I RESPECT a ton. Food for thought....


Dr. Neil Frank: Isaac could continue moving west

http://www.khou.com/community/WATCH-Dr- ... 20065.html

SMH

[WeatherGuesser]

From the 7PM:

STORM SURGE...THE COMBINATION OF A STORM SURGE AND THE TIDE WILL
CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY RISING
WATERS. THE WATER COULD REACH THE FOLLOWING DEPTHS ABOVE GROUND IF
THE PEAK SURGE OCCURS AT THE TIME OF HIGH TIDE...

* SOUTHEAST LOUISIANA AND MISSISSIPPI...6 TO 12 FT
* ALABAMA...6 TO 9 FT
* SOUTH-CENTRAL LOUISIANA...3 TO 6 FT
* FLORIDA PANHANDLE...3 TO 6 FT
* FLORIDA WEST COAST INCLUDING APALACHEE BAY...1 TO 3 FT

THE DEEPEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST IN AREAS OF
ONSHORE FLOW. SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING
OF THE SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT
DISTANCES. FOR INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE
PRODUCTS ISSUED BY YOUR LOCAL WEATHER SERVICE OFFICE. NEAR THE
COAST...THE SURGE WILL BE ACCOMPANIED BY LARGE AND DANGEROUS WAVES.

[hurricanes1234]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Yes, Isaac simply CANNOT be compared to Katrina. Here's why:

Isaac is a 70 mph tropical storm. Katrina was a 175 mph Category 5 and briefly held the record of being the strongest storm in the Gulf of Mexico, until it was surpassed by Rita.
Isaac is suffering from internal problems - which are inhibiting significant intensification. Katrina had a very large and well-defined eye, and had a CLOSED eyewall.

These are the two most important reasons why I can never compare Isaac with Katrina. Though Isaac still has the opportunity to intensify, I highly doubt it would become a Category 5 - this means that it must enter an intense round of explosive intensification to reach 160 mph, let alone 175 mph. For explosive strengthening to occur, conditions in the cyclone and in its surroundings must be perfect - and as we can see, Isaac is suffering from a poorly-defined circulation, according to one of the earlier updates on the thread. Also, external problems here include dry air and modest wind shear, which means that there is a <1% chance of explosive strengthening. Now, if the shear abates and Isaac manages to mix out the dry air, that would be a totally different story, but the most that should occur, in that case, would be rapid strengthening, still leaving explosive intensification at a low chance, around 5% for the highest.

[rainstorm]

if isaac can slow even more it can deepen.

[EBrads146]

SouthDadeFish, thank you for those microwave scans. They confirmed what I had been thinking the last few frames- dry air again.

Isaac is certainly trying to get its act together. Looks like a few more cloud tops are beginning to pop up in the western part of the center. But I'm starting to think that (mercifully) conditions have conspired against it for the long run.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Lane]

Dumb question, but is the NE quad collapsing? Or is that just a huge gulp of dry air?

[wxman57]

Those microwave scans are a bit dated. Satellite imagery over the past 2 hours indicates a significant drop-off in convection. Squalls had been wrapping around the east and northeast side earlier but those died out. Even the convection to the southwest of the center is now diminishing. Oh, and I don't see any west movement to Texas. Even the GFDL now says SE LA. Of course, that may mean it can't possibly go there...

[wxman57]

Dumb question, but is the NE quad collapsing? Or is that just a huge gulp of dry air?

Not dumb at all, see my post right below yours.

[Shawee]

I'm beginning to think the angle of attack is going to be a bigger issue that wind speed, as it could push more water into the river and channels leading to NO.

But since no one wants to address the question on the surge potential on the levees .....

if it comes in at 75 mph i just dont think it will be a big deal. 110 would have been a different story.

Again, it's NOT the wind speed. It's the size of the wind field, the amount of water displaced and the direction in which the displaced water is pushed.

The levee systems are different in different parts of the state. Some only have smaller levees as the protect relatively few folks. Depending all of the relevent forces, especially direction, one of these could be comprimised. I AM NOT PREDICTING THIS WILL HAPPEN.. just trying to give perspective. Maybe a cattle or cane field somewhere.
The major systems rebuilt around the Greater New Orleans area and westbank should not be threatened by anything Isaac could throw at it. They are now designed not to fail even if overtopped, a VERY big difference. One of the best things we got out of K/R was a new, professional Flood Authority and a massive investment in the main portions of the system (thanks!). It also isololated and took out of the main system the faulty "walls" that suffered catostophic engineering failure (they basically fell over). They are far from perfect, but light years ahead of where we were.
Sorry for the long-windedness... and I don't want to start a debate here. Now back to Isaac! The NHC track is what I am preparing for, but I still can live in hope.

[Lane]

Thank you wxman57

[Tireman4]

This is from Dr. Neil Frank, former NHC director and someone that I RESPECT a ton. Food for thought....


Dr. Neil Frank: Isaac could continue moving west

http://www.khou.com/community/WATCH-Dr- ... 20065.html

SMH

And you are shaking your head why? I put this out here for food for thought. I did not say it would go anywhere. I have degrees in history, not meteorology. I know pretty much next to nothing. I will say this, I respect any meteorologist. I certainly respect the former head of the NHC. Thanks for your consideration.

[Dean4Storms]

The center now coming into view on long range radar?

http://radar.weather.gov/ridge/radar.ph ... 1&loop=yes

[denisec]

This is from Dr. Neil Frank, former NHC director and someone that I RESPECT a ton. Food for thought....


Dr. Neil Frank: Isaac could continue moving west

http://www.khou.com/community/WATCH-Dr- ... 20065.html

Saw that and was utterly mystified at the timing of it--right when the models all seem to be shifting east and it seems time to be less worried about it. Wondering just where that is coming from or if it was an older video posted many hours after it should have been?

Mind you, I've been permanently paranoid about tropical weather ever since the Rita evacuation and have become somewhat obsessive about learning about weather forecasting in the years since and paying close attention whenever anything is in the Atlantic that might develop (drives my boyfriend batty) , so I'm not one to judge cautioning people to pay attention--it just seems to make little sense at this point (a day or so ago, would have made more sense, IMHO).

[KimmieLa]

Those microwave scans are a bit dated. Satellite imagery over the past 2 hours indicates a significant drop-off in convection. Squalls had been wrapping around the east and northeast side earlier but those died out. Even the convection to the southwest of the center is now diminishing. Oh, and I don't see any west movement to Texas. Even the GFDL now says SE LA. Of course, that may mean it can't possibly go there...

Any chance this storm is done? No more strengthening before landfall?

[rainstorm]

it does appear to be gettint a bit better.