Hurricane Isaac continues to organize as it nears landfall

By: Angela Fritz , 9:31 PM GMT on August 28, 2012

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Isaac gained hurricane status this afternoon after hurricane hunters found winds of 76 mph and a minimum central pressure of 975 mb, and continues to become more organized. In their 5pm EDT update, the National Hurricane Center said Isaac has maximum sustained winds of 80 mph, and is moving northwest at 8 mph--a slow down from yesterday at this time. Satellite loops show that Isaac has gained thunderstorm activity on the southeast side, but is battling dry air to the north. Isaac still appears to be forming an eye wall, though is struggling to do so. Winds have been increasing as Isaac approaches, up to 60 mph has been recorded by buoys close to the shore. Winds off Lake Pontchartrain have varied around 35 mph from the northwest this afternoon. So far New Orleans (KMSY) is seeing wind gusts up to 40 mph, with light rain.


Figure 1. Isaac imagery from the high resolution Terra satellite at 12:30pm EDT, just before becoming a hurricane.

Some rain and thunderstorm activity has reached the northern Gulf Coast this afternoon, with Isaac just over 100 miles southeast of New Orleans. Radar shows thunderstorms from Pensacola to New Orleans. Storm surge has begun to impact the coast, as well, particularly in Mississippi and Louisiana, where reports are that water is "up to cars" in some areas. Many streets are closed in Ocean Springs and Pascagoula, Florida due to surge flooding.

Water levels so far (above mean):

• Shell Beach, LA: 8 feet
• New Canal Station (New Orleans): 2.7 feet
• Bay St. Louis, MS: 5.6 feet
• Pascagoula, MS: 4.4 feet
• Dauphin Island, AL: 3.7 feet

Hurricane Isaac will likely make landfall tonight as a category 1 around midnight CDT, but will still have enough energy and warm water available to maintain hurricane strength for a few hours inland. Isaac will likely continue to strengthen a bit before landfall, but given the large wind field, rapid intensification is unlikely. The storm surge threat could then continue along the Louisiana, Mississippi, Alabama coasts through mid-afternoon on Wednesday, as winds will continue to blow from the east, and then from south, as the storm moves northwest past New Orleans. Should the peak surge coincide with peak tide, the highest storm surge, anywhere from 6 to 12 feet, is expected in Louisiana and Mississippi. Alabama could see a storm surge around 4 to 8 feet.


Figure 2. Rainfall forecast from the HPC through Sunday morning. The lime green bullseye over Gulfport, MS is a value of 15+ inches.

The Hydrometeorological Prediction Center is forecasting around 15 inches of rain to fall around Gulfport, Mississippi, and up to 12 inches of rain to fall near New Orleans, Louisiana by Sunday morning. As Isaac tracks north after landfall, it will bring some much-needed rain to the drought-stricken Mississippi Valley region, particularly west of the Mississippi River. While anywhere from 3-5 inches of rain is expected from Arkansas to Indiana by Sunday, and the Arkansas, Missouri, and Illinois drought will benefit, this is not a drought buster. The driest parts of the country are in the Central Plains states, and this rain will be too little to have a meaningful impact.

Monitor Hurricane Isaac online:
Track, forecast, and current observations
Radar and weather stations
Satellite
Webcams


Angela

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Quoting facetracker:
Ladies and gentlemen, boy's and girls, i believe we have a landfall!

Landfall is center, not eyewall.
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i cant believe how much this thing has tightened up and exploded in the last few hours. The difference between now and earlier is huge. Kind of like Beryl but on a larger scale. Im used to storms weakening as they get closer to shore. This really is amazing. Getting more scary now that it doesnt look like a struggling ts.
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Quoting presslord:


Oh, God!! Please tell me you just made that part up...


That is a FACT. This sinkhole has been growing for almost a month and is VERY near to a salt dome used to store butane. The sinkhole is well norrth of Lafeyette in Assumption parish.

This is not joke. Full article below:

louisiana-activates-4000-national-guardsmen-secur ing-sinkhole-equipment
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593. lopaka001

Any info from that station on the date of Katrina?

The river at Venice has me a little worried.
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How goes the birthing?

Quoting Patrap:
Big bada BOOM,,power went down, but Luckily we are on The Children's Hospital Priority Leg here.

So itsa up again for now.

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This is why you don't give up on tropical cyclones in the Gulf that have extremely favorable upper level conditions with outflow channels everywhere.
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We are lucky this hadn't happened a day or two ago because we would have a major hurricane headed right for NOLA. Isaac is, I think, a little stronger than 80mph but he is still causing a good amount of damage.
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Quoting Neapolitan:
Hey, another new toy...

BEGIN
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invest_al982012.invest
FSTDA
R
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040
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201208282320
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 98, 2012, DB, O, 2012082818, 9999999999, , , , , , METWATCH, , AL982012
AL, 98, 2012082818, , BEST, 0, 119N, 280W, 20, 0, DB, 0, , 0, 0, 0, 0,



LOL
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Isaac taking a deep breath and The Mayors office just sent a 300K robo-call on "status" to all Bell System Phones in the Greater Metro Area.

Member Since: July 3, 2005 Posts: 434 Comments: 133303
Quoting facetracker:
Ladies and gentlemen, boy's and girls, i believe we have a landfall!

Radar shows the center is still drifting just off the coast.

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lol
Quoting trHUrrIXC5MMX:


why do you quote what he said already...?? not cool
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I think its not really worth it to hypothesize over whether this would be a major if it had looked like it did now in the Gulf, since certain aspects of this storm which make it so dangerous probably was responsible for keeping it from becoming a stronger storm in terms of the category.
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Quoting mobilebayal:


Now is that the mobile al in Alabama, or the mobile al in Mississippi?...lol
I'm in mobile near semmes by magnolia grove golf course, beginning to wonder if i'm ever gonna get anything out of this storm, so far barely about .10 of rain and highest wind maybe 10-15mph
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Quoting TomballTXPride:

Unfortunately too late to save the crops, but the forests in Missouri and Southern Illinois in the "Exceptional Drought" category will be welcoming it.


Agree, I just drove up to Indiana about a month ago and it looks like TX did last year. The crops are gonners.They need rain up that way something terrible
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Quoting SFLWeatherman:
We now hvae 98L


why do you quote what he said already...?? not cool and by the way its HAVE!
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We now hvae 98L
Quoting Neapolitan:
Hey, another new toy...

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FSTDA
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END
INVEST, AL, L, , , , , 98, 2012, DB, O, 2012082818, 9999999999, , , , , , METWATCH, , AL982012
AL, 98, 2012082818, , BEST, 0, 119N, 280W, 20, 0, DB, 0, , 0, 0, 0, 0,
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Oh but he didn't.Lucky for our Gulf coast residents :).
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New Max Water Level reached!

Shell Beach, LA 8761305

Winds: 46 mph at 30.0
Water Levels: 9.0 Ft
Historical Maximum Water Level: Sep 1 2008, 8.78 ft.

Member Since: February 19, 2007 Posts: 0 Comments: 239



WIND PROJECTIONS
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4 minutes ago:

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Quoting TropicalAnalystwx13:
Had this happened 24 hours ago Isaac would be a major at landfall.


hrm. I think we might get real station readings in the post, it might get upgraded; we may have no clue to the real strength of this thing. Weird interactions going on.
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Quoting HCW:
lightning showing up in the eyewall meaning this is a hybrid and not fully warm cored


I've been wondering that for a few days. Talked my self out of it a couple times based on Isaac getting stronger overnight, which meant he's warm core.

There is also a case to be made that (although rare) lightning near the core of a hurricane means it's likely to be more violent.
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Ladies and gentlemen, boy's and girls, i believe we have a landfall!
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RAINFALL PROJECTIONS-




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Quoting redwagon:

Yeah.. my ears are two feet high now.. the habited area above the sinkhole is 2-300 people, and they've been under evacuation orders for a month. I'm thinking they'd get gone with Isaac water coming in to dissolve the NE side of the sinkhole that the salt dome occupies...gov was quite serious about this hole blowing.


how big of an explosion are we talking about if the storage dome next to it blows?
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This storm is really getting its act together, and I think the fact this storm might have a couple more hours over water or at least swampland is concerning enough.

The outflow of this storm is very symmetrical and the inner core appears to be trying to become more symmetrical.

It even looks like on local radar that the smaller eye is trying to wrap some storms around its Western side.
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Quoting presslord:


I found my last one by putting food coloring into water and pouring it where I thought the issue might be...worked rather well....


it has taken me 10 minutes to figure out what you were putting food coloring in.
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Quoting redwagon:

Yeah.. my ears are two feet high now.. the habited area above the sinkhole is 2-300 people, and they've been under evacuation orders for a month. I'm thinking they'd get gone with Isaac water coming in to dissolve the NE side of the sinkhole that the salt dome occupies...gov was quite serious about this hole blowing.

Wow, that stuff is scary!
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May be the most pretty storm all year
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Hey, another new toy...

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invest_al982012.invest
FSTDA
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NOTIFY=ATRP
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INVEST, AL, L, , , , , 98, 2012, DB, O, 2012082818, 9999999999, , , , , , METWATCH, , AL982012
AL, 98, 2012082818, , BEST, 0, 119N, 280W, 20, 0, DB, 0, , 0, 0, 0, 0,
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Quoting AussieStorm:
Brian Osborn or CycloneOZ is in NOLA he's getting busted by the police.



This is absolutely hilarious. He was putting down a few cold ones right before the cops showed up.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Quoting nola70119:
8 mph? I can bicycle faster than that.....big problems.

Usian Bolt can run around 2.25 times that.
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No way possible for Houston to get any part of this storm. It's 350 miles from new Orleans, granted it's a big system but it has to be close to 700 miles long to even slightly effect Houston. Houston lucked out big time
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575. HCW
Quoting TropicalAnalystwx13:

Uhm, what? Lightning is just indicative of very intense thunderstorms embedded within Isaac's spiral bands and has nothing to do with whether the storm is warm or cold core. How would Isaac be cold core to begin with?

Lightning with an eyewall is also one of the first signs of rapid intensification.


Sir can you please post a source to that info so that you can help others be better informed on the tropics
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Quoting HCW:
lightning showing up in the eyewall meaning this is a hybrid and not fully warm c
ored

Lightning in the eye wall means strong tubulance is occurring in a hurricane's eye. This is not a hybrid hurricane at the present time
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Look at that band off Florida and how its now part of the flow.....incredible
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Quoting nola70119:
If i am not mistaken that eastern band off of Florida is actually wrapping from the north around and feeding the storm's west side?


Link

Some of us were discussing this earlier - it appears that all of the storms that are forming off the east coast are now connecting back to Isaac.
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570. Skyepony (Mod)
Quoting datasmasher:
Let me rephrase my question. This is the first hurricane season I have a weather station setup (one that post to Weather Underground). From a meteorological perspective, is it common for the pressure to go down on the western edge of a storm (technically far west)?


In a storm this size yes..
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Quoting zoomiami:


Stay safe, you and your family.
Quoting zoomiami:


Stay safe, you and your family.


Dat be da plan.

We have the Parlor Doors closed to the North side where the winds have switched around to.

Also we have the Stair foyer cove for our TVS safe room.
hopefully that will not be needed but one needs a action plan.

Now.




Member Since: July 3, 2005 Posts: 434 Comments: 133303
Quoting TropicalAnalystwx13:
Had this happened 24 hours ago Isaac would be a major at landfall.



that's what they get for waiting for the last minute.
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Link
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Quoting Masquer08er:
mobile al I'm in Springhill area


Now is that the mobile al in Alabama, or the mobile al in Mississippi?...lol
Member Since: August 17, 2007 Posts: 0 Comments: 1098
Quoting Patrap:
really cranking up here now. Wooof


stay safe,lot more to come.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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