ATL: ISAAC - Post-Tropical - Discussion

[WxGuy1]

Besides the improving radar structure I mentioned earlier, the satellite presentation of Isaac looks the best we've seen it so far. Gone are the times of a missing hemisphere of convection -- we aren't seeing the dry air, "half-eaten" satellite appearance from yesterday and earlier today. Isaac is much more symmetric and looks like it's poised for intensification. Again, fortunately, this is happening NOW, when the center of the eye is 15-20 miles off shore, than yesterday at this time. Color me impressed that it got its act together after all...

[Frank P]

yeah he's getting really close, has about 2-3 more hours to tighten up... if he continues on expected track.. still best I've seen him on radar right now...

[windnrain]

Ok, so, we are really close to the hurricane now.

Can someone, anyone, tell me what kind of effects we will feel in BR?

[mcheer23]

Impacts for Mobile, Alabama? Seems like not much...?

[SunnyThoughts]

[Weather Watcher]

I can't believe those people on orange beach!!!

[BigEasy]

I know many folks make reference to landfall, as a benchmark for tropical systems. One difference with landfall in SELA, such as where Isaac is doing so, and more so in this specific location of SELA; the marsh is about 75-80% water, all the way up to about 10-15 miles south of the city of New Orleans as the crow flies. I bring this to lite, simply because so many have and understand a landfalling storm, typically loses intensity and does not increase is strength once it has made landfall. We have loss TONS of hard land in Katrina and then Gustav the following year.

Isaac could maintain a good portion of his intensity all the way up to the city of New Orleans. As far as intensifying once over the vast marsh areas; would be a stretch though.

Fly into the city anywhere from a southern direction one time, and you will get the true picture of the landscape. It is like no where else, where tropical systems make landfall.

[lester]

NOAA Recon found pressure of 973.8 mbs

dropsonde reported 971 mbs with a 5 kt wind

[ozonepete]

Besides the improving radar structure I mentioned earlier, the satellite presentation of Isaac looks the best we've seen it so far. Gone are the times of a missing hemisphere of convection -- we aren't seeing the dry air, "half-eaten" satellite appearance from yesterday and earlier today. Isaac is much more symmetric and looks like it's poised for intensification. Again, fortunately, this is happening NOW, when the center of the eye is 15-20 miles off shore, than yesterday at this time. Color me impressed that it got its act together after all...

Well said, wxguy. That said, a hurricane intensifying at landfall is much worse than a weakening one. It has too lose all of that momentum. That's why I would think places like the MS coast and all of SE Louisiana including NOLA have to be really vigilant until the center has passed well away...

[Pork Sandwich]

Longtime lurker making a post alert! I have been in every corner of south LA including where Isaac is about to make landfall. There is little to no land in that area. It's mostly marsh, and you typically see very little weakening of land falling storms in the state until they get north of I-10. Case in point, Hurricane Lili in '02 made landfall as a cat 1 and was still a cat 1 in my stomping grounds near Alexandria. If this thing wobbles around the marsh for awhile, don't discount it holding it's strength for a bit. I'm not saying RI is possible inland, but with the increase in structure over the last several hours, I'd guess there won't be much weakening.

This is not an official forecast.

[deltadog03]

Starting to move north....looks close to the coast....

[TheDreamTraveler]

NOAA Recon found pressure of 973.8 mbs

dropsonde reported 971 mbs with a 5 kt wind

Now that the eyewall is fully intact, this thing may be on its way to gradually or rapidly strengthen. Thankfully it's now rather than earlier.

[GCANE]

Core has heated and tightened up as well.

Latest AMSU analysis, 1932Z:

http://amsu.ssec.wisc.edu/archive/2012/ ... _xsect.gif


At 0920Z:

http://amsu.ssec.wisc.edu/archive/2012/ ... _xsect.gif

[monicaei]

It is very near to the coast now, probably less than 100 miles away.

Look to me more like about 10 or 15 miles.

Maybe people have different ideas about what qualifies as land?

Anything south of the birds foot isn't really "Land". That red line is at best marsh, at worst, gulf that hasn't been updated on the charts.

Ever seen the overlay from google earth over the old NOAA charts? I'd wager a conservative estimate is 50% is simply open water

[BigEasy]

Besides the improving radar structure I mentioned earlier, the satellite presentation of Isaac looks the best we've seen it so far. Gone are the times of a missing hemisphere of convection -- we aren't seeing the dry air, "half-eaten" satellite appearance from yesterday and earlier today. Isaac is much more symmetric and looks like it's poised for intensification. Again, fortunately, this is happening NOW, when the center of the eye is 15-20 miles off shore, than yesterday at this time. Color me impressed that it got its act together after all...

No doubt but it does have that classic and commonly referred to buzzsaw look, without the teeth of the blade; only the shape. Thank goodness.

[ozonepete]

Hey WxGuy1, have you seen a report from KBVE recently? I haven't seen one since 1551 GMT and think they may have shut down.

[Portastorm]

Longtime lurker making a post alert! I have been in every corner of south LA including where Isaac is about to make landfall. There is little to no land in that area. It's mostly marsh, and you typically see very little weakening of land falling storms in the state until they get north of I-10. Case in point, Hurricane Lili in '02 made landfall as a cat 1 and was still a cat 1 in my stomping grounds near Alexandria. If this thing wobbles around the marsh for awhile, don't discount it holding it's strength for a bit. I'm not saying RI is possible inland, but with the increase in structure over the last several hours, I'd guess there won't be much weakening.

This is not an official forecast.

Thanks for making your posts and nice to see you posting. You raise some valid points which we all should keep in mind. Stay safe over there!

[WeatherGuesser]

At the 310° stated in the 5PM, it's 20 miles from that small point of land. If they count that as landfall, it should be around two hours from now. If it misses that, the next land coast on the same heading is about 60 miles, so that would be around midnight or so at 8MPH.

[MBryant]

I think you're onto something. The outlined area some are looking at as LAND is often underwater and surely is with hurricane tides. This along with coastal erosion makes those outlines very suspect.

[GCANE]

New and very large hot tower seems to be firing up on the east side of the LLC

http://www.nrlmry.navy.mil/htdocs_dyn_p ... xico.0.jpg