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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wow, 40kt initial intensity
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1512. guygee
Quoting robj144:

Ummm... shouldn't they be designed exactly the opposite way? You know, with the concrete on the outside, so that wouldn't happen.
The waves would quickly erode the earthen support from wave action and currents if the earth was on the inside. Concrete on the waterside, definitely the better design choice.
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Quoting WetBankGuy:


Looks like a north jog on Slidell radar, local Met says west. Just wobbling I think.

If anyone gets any near-time data out of recon please post it ASAP for all the power goes out in NOLA.

Thanx.



here is a link to wwltv no

http://www.wwltv.com/weather/interactive-radar/ra dar?map=sela124&c=n
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1510. angiest
Quoting IndySuz:

TWC said they were the first parish to order mandatory evacuation.


With good reason. According to WP, a little over 65% of the Parish is water. What's left, isn't far above water.
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Hurricane ISAAC
...CENTER OF ISAAC OVER WATER AGAIN... ...HEAVY RAINS...HIGH WINDS...AND STORM SURGE FLOODING CONTINUE... ...U.S. Warnings in Effect...
9:00 PM CDT Tue Aug 28
Location: 28.9°N 89.7°W
Moving: NW at 8 mph
Min pressure: 968 mb
Max sustained: 80 mph
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Quoting alvarig1263:
OFFICIAL! **We have Tropical Storm Kirk**

11/4/0 not bad.
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Quoting hurricanehunter27:
He has not made landfall yet. He is stalled and drifting south as of right now off the coast.


Splitting hairs bro...
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1505. Gorty
Quoting alvarig1263:
OFFICIAL! **We have Tropical Storm Kirk**



Many named system in August.
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Breaking News Storm ‏@breakingstorm
Entergy New Orleans Inc. is reporting more than 190,000 customers without power in Louisiana - @breakingweather
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OFFICIAL! **We have Tropical Storm Kirk**

45 MPH Winds.

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Quoting dogsgomoo:
Er. No. What? That's not on @TWCBreaking.
he said it was 2 ft from the top of the levee not coming over yet.
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Quoting LongIslandXpress38:


So Isaac basically made landfall as a 968 mb Cat 1; wow, if he had gotten together on Sunday, New Orleans would have been jacked up..
He has not made landfall yet. He is stalled and drifting south as of right now off the coast. I am not counting a little outcrop of the Mississippi river as a real landfall. Was only over it for about 20-30 minutes anyway.
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Hurricane Central ‏@twc_hurricane
Mobile County, AL EMA: west end of island is under water #Isaac #ALwx

Andrea Butera ‏@AndreaButera
Per the Mobile County, AL EMA: The west end of Dauphin Island is under water. Everyone has evacuated. #Isaac #ALwx
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Quoting MoldyinMS:
If it is female how about caasi? blockquote class='blogquote'>Quoting LurkyMcLurkerson:


Either gender, you should name that one Isaac.



Good grief, what happened to that? I meant How about caasi
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Hurricane Central ‏@twc_hurricane
Tides are nearly 10 ft above normal at Shell Beach on the south end of Lake Borgne east of New Orleans. #Isaac
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it has stalled for over 2 hrs. and the little hair bob has he is pulling out right now :)in mandeville la. less than a mile off lake and nothing more than a few small showers and some gust of about 30 every now and again. not too bad right now, but bob says its coming!!!! anyone thinks they can tell me when we will see some hurricane force sustained winds or if we even will see that? thanks in advance :)
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Quoting Levi32:
On TWC one of the people from the parish said the water levels are starting to diminish from what they were, which is good news.
Seems like questionable info considering the south wind has yet to reach the mouth of the Mississippi river.
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Anybody have any an idea on how much rain has fallen in NOLA so far? It has been constant the last few hours, but if the wind wasn't blowing it would be a light rain.

Power is still steady and still receiving tv signal. Sounds like wind is picking up, so who knows for how much longer.
Member Since: August 26, 2012 Posts: 0 Comments: 7
Quoting Levi32:
High tide looks like it comes at about 9am local time at Grand Isle, LA:

Well it looks like it will only rise another foot at that location based off the graph. Who knows though, could make the difference with the levees.

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Quoting Levi32:
On TWC one of the people from the parish said the water levels are starting to diminish from what they were, which is good news.


low tide.. Mobile's next high tide is 10 am in the morning so LA should be an hour or so earlier
Member Since: August 3, 2006 Posts: 133 Comments: 20645
Quoting Levi32:
On TWC one of the people from the parish said the water levels are starting to diminish from what they were, which is good news.


So Isaac basically made landfall as a 968 mb Cat 1; wow, if he had gotten together on Sunday, New Orleans would have been jacked up..
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1490. Ryuujin
Only issue is that we're at low tide at the moment and if Isaac stalls enough the storm surge is still going to be going on.
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Quoting Thing342:
No, Kirk. Joyce got torn apart by shear.


Oh my goodness I can't believe I forgot Joyce...goes to show you how tired I am. Thank you very much, I'll fix that.

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1488. Mikla
Based on Base Velocity Radar, the West motion appears to have stopped (for now?)...
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Quoting leftlink:


The system has a history of suddenly relocating the circulation towards the ocean and giving the finger to the models. Then it resumes motion in the direction originally predicted by the models. This could still happen, certainly.

However that only happens when there is a blow-up of convection over the ocean, creating sort of a "magnet" to draw the weak center back underneath.

So watch the water vapor loop on Infrared (geos-14) and if you see that happening just south of where the center is headed, sure it could side step part of the way to Houston. But that's a big IF.


Well, the most recent center fix from the Air Force aircraft was 28.75N 89.62W - while the previous fix from the same plane at the same level was 29 N 89.55W. In fact, the aircraft had to circle back south to find the center, when it didn't appear where it was expected.

In other words, the center of the storm just moved 0.25 degrees South. Steady at 968MB, though.

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Quoting dexware:


Go look at their outage map... a couple of hours ago it the metro NOLA area was majority green. Looks like blood splattered all over the map with all the red outages.

With Isaac stalled/drifting the winds will continue to knock out power.
Eyewall is almost closed.
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1485. Levi32
Quoting TropicalAnalystwx13:

Yeah...not sure why it would rise and then fall like that.


The tide is still going out I think, but remember the heavy rain upstream could make the river rise from the upstream direction, increasing the pressure against the still oncoming surge, so the water could rise again.
Member Since: November 24, 2005 Posts: 635 Comments: 26731
Quoting LADobeLady:
The inside of the levees are concrete the outside is earthen.  The water is splashing over, not topping completely,  They are worried that the splashing will erode the grass thus causing a failure.  


Not there they aren't....all earthen
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1483. IndySuz
Quoting leftlink:


These are the ones made of earth not concrete, correct? Hope the whole parish was under mandatory evacuation

TWC said they were the first parish to order mandatory evacuation.
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any other NOLAs still up?
70119
20:54 Local
pressure holding 993mb
power intermittent
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Quoting TropicalAnalystwx13:

Yeah...not sure why it would rise and then fall like that.

Probably low tide, which is around now...we don't need tides to rise in the dark... that is for sure
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Weather Underground ‏@wunderground
Offshore Oil Port west of center of #Isaac reporting sustained winds 72 mph, gusting to 83 mph.
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1478. robj144
Quoting TropicalAnalystwx13:

Yeah...not sure why it would rise and then fall like that.


Well, if the winds shifted 180 degrees as it does when the eye passes directly over, it would push the water back out. I doubt that has happened.
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1476. dexware
Quoting wxchaser97:
wunderground Entergy is reporting ~150,000 people without power. But crews can't work unless winds 30 mph or less
Already 150,000 and Isaac is taking his very slow time.


Go look at their outage map... a couple of hours ago it the metro NOLA area was majority green. Looks like blood splattered all over the map with all the red outages.
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Guys what's going on?

I lost power about 2 hours ago...

but it's back on for now.

Crazy because we probably haven't had a gust above 35 or so.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting WetBankGuy:


Looks like a north jog on Slidell radar, local Met says west. Just wobbling I think.

If anyone gets any near-time data out of recon please post it ASAP for all the power goes out in NOLA.

Thanx.


Actually its a wobble to the south per recon. Isaac has been and still is one difficult storm.
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Quoting Levi32:
On TWC one of the people from the parish said the water levels are starting to diminish from what they were, which is good news.

Yeah...not sure why it would rise and then fall like that.
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Hey, Pat -

I didn't count the number of "O Wows' - how many pups so far?
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1470. robj144
Quoting LADobeLady:
The inside of the levees are concrete the outside is earthen.  The water is splashing over, not topping completely,  They are worried that the splashing will erode the grass thus causing a failure.  



Ummm... shouldn't they be designed exactly the opposite way? You know, with the concrete on the outside, so that wouldn't happen.
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She about stalled or what? Very slow drift right now? Looks like the eye is done shrinking?
Member Since: February 2, 2010 Posts: 0 Comments: 1635
1468. Levi32
On TWC one of the people from the parish said the water levels are starting to diminish from what they were, which is good news.
Member Since: November 24, 2005 Posts: 635 Comments: 26731
Quoting MAweatherboy1:
Isaac has not moved in the last hour from what I see on radar. I think we may have an official stall.


Looks like a north jog on Slidell radar, local Met says west. Just wobbling I think.

If anyone gets any near-time data out of recon please post it ASAP for all the power goes out in NOLA.

Thanx.

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This is getting really serious. Core is tightening up very quickly...

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Quoting FutureWx6221:
28/2345 UTC 23.7N 44.6W T2.0/2.0 11L -- Atlantic

Joyce at 11?
No, Kirk. Joyce got torn apart by shear.
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1464. isuxn2
Anyone seen STORMTOP? Is he out inspecting levee's?
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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