Hurricane Isaac hits Louisiana, driving dangerous storm surges

By: Dr. Jeff Masters , 2:27 AM GMT on August 29, 2012

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Hurricane Isaac is ashore over Southeast Louisiana, having officially crossed the coast on the Mississippi Delta 90 miles southeast of New Orleans at 7:45 am EDT on August 28. Isaac intensified right up until landfall, striking with 80 mph winds and a central pressure of 970 mb. The storm's large size and large 50 - 60 mile diameter eye kept the intensification rate slow today, but it came quite close to becoming a significantly more dangerous storm. That's because at landfall, Isaac was in the midst of establishing a small inner eyewall within its large 50-mile diameter eye, a very rare feat I've never seen before. Usually, when an eye first forms, it gradually contracts, eventually becoming so small that it becomes unstable. An outer concentric eyewall then forms around the small inner eyewall, eventually becoming the only eyewall when the inner eyewall collapses. But Isaac is a very unusual storm that has continually surprised us, and this inside-out concentric eyewall formation fits the storm's unusual character. The storm isn't in a hurry to move fully inland, and has slowed down to a crawl this evening. This will give the storm the opportunity to keep its center mostly over water a few more hours, and maintain hurricane strength into the early morning on Wednesday.


Figure 1. Radar reflectivity image from New Orleans as Isaac made landfall at 6 pm CDT August 28, 2012.

A dangerous storm surge event underway
Isaac is bringing large and dangerous storm surge to the coast from Central Louisiana to the Panhandle of Florida. At 10 pm EDT, here were some of the storm surge values being recorded at NOAA tide gauges:

6.2' Waveland, MS
9.9' Shell Beach, LA
3.0' Pensacola, FL
4.4' Pascagoula, MS
3.4' Mobile, AL

The 9.9' storm surge at Shell Beach, which is in Lake Borgne 20 miles southeast of New Orleans, exceeds the 9.5' surge recorded there during Category 2 Hurricane Gustav of 2008. Research scientists running a Doppler on Wheels radar located on top of the 16' levees in Plaquemines Parish near Port Sulphur, LA, reported at 8:30 pm EDT that a storm surge of 14' moved up the Mississippi River, and was just 2' below the levees. Waves on top of the surge were cresting over the west side of the levee. Needless to say, they were very nervous. Over the past hour, the surge has retreated some, and waves were no longer lapping over the top of the levee. This is probably due to the fact that we're headed towards low tide. A storm surge of 9.5' has moved up the Mississippi River to the Carrrollton gauge in New Orleans. This is not a concern for the levees in New Orleans, since the storm surge has now brought the river up to 2.5' above its normal water level, which was 7' low due to the 2012 U.S. drought. The highest rise of the water above ground level will occur Wednesday morning over much of Southeast Louisiana, Mississippi, Alabama, and the western Florida Panhandle, when the tide comes back in. It is clear now that this storm surge event will be as dangerous as that of Category 2 Hurricane Gustav of 2008. One piece of good news: NWS New Orleans successfully launched their 00Z balloon. However, their discussion noted the atmosphere is "saturated or nearly saturated" all the way up to 470mb, or 20,000 feet. Precipitable water was 2.76 inches, which will be ripe for extremely heavy rainfall.


Figure 2. Tide gauge data from Shell Beach, located on the south shore of Lake Borgne, just east of New Orleans. The green line shows the storm surge. The red line is the storm tide, the height of the water above Mean Sea Level (MSL.)

Portlight disaster relief charity responds to Issac
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, have mobilized resources in advance of the arrival of Hurricane Isaac. Their crew, including 2 EMTs, is at the Biloxi Special Needs Shelter, and will be caring for shelter dwellers and doing rescues of people who call for help. Another team will be surveying all the shelters in the area to ensure that they are accessible to all people. You can donate to Portlight's disaster relief fund here.

I'll have more in the morning. Hunker down, New Orleans. It's going to be a long night.

Jeff Masters

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000
URNT12 KNHC 290802
VORTEX DATA MESSAGE AL092012
A. 29/07:27:40Z
B. 29 deg 09 min N
090 deg 22 min W
C. 700 mb 2843 m
D. 55 kt
E. 249 deg 13 nm
F. 354 deg 62 kt
G. 256 deg 16 nm
H. 969 mb
I. 12 C / 3046 m
J. 17 C / 3044 m
K. 8 C / NA
L. OPEN W
M. C50

N. 12345 / 07
O. 0.02 / 0.5 nm
P. AF307 3409A ISAAC OB 05
MAX OUTBOUND AND MAX FL WIND 78 KT SE QUAD 07:48:10Z

Minimum 700 mb height decreased by 43 meters, a pretty big drop in 2 hours, but a 1 mb pressure increase? Interesting..
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Quoting AussieStorm:
Jennifer Hale ‏@JenHale504
Plaquemines Parish releasing reverse 911 for Braithwaite residents: levee overtopping significantly on east bank. Residents must leave now.


Any more word on this? Terrifying to think of.
Member Since: October 14, 2008 Posts: 0 Comments: 179
Quoting jake436:
Again, you're looking at live shots from NOLA. NOLA is NOT on the coast. NOLA is not the center of the Hurricane Universe. Chalmette received over 4" of rain between 12 midnight and 2 pm. That's over 2"/hour. I would surmise from radar that it's probably up to 7" from midnight until 3am in Chalmette. Three hours. 7". That's not a lot of rain for a hurricane? FL got 15" of rain, but it wasn't in 6-8 hours.


Thanks for the information.
Member Since: April 11, 2009 Posts: 0 Comments: 18
1116. jake436
Quoting leftlink:
NDBC Summary at 3am CDT.

Grand Isle Buoy just got wind shift to south at 3:00am CDT. Storm surge should increase there now.

LINK


South of Ponchatrain buoy just recorded 63.9kt (73.5mph) winds from the ENE at 1:06am CDT

LINK


Shell Beach buoy recorded 68kt gust from the ENE at 10:30pm CDT

LINK


Eye passed directly over LOP1 station at 11:50am CDT with winds decreasing to 7kts, central pressure 28.59in or 968mb.

LINK


Seven consecutive hourly readings with sustained winds of 60mph or more from the north at buoy just south of Houma, Louisiana

LINK
Good info. The first thing about Grand Isle, for what it's worth, Grand Isle gets storm surge from all sides. It was already under storm surge from the north-Caminada and Barataria Bays. Now it will get it from the south-the Gulf. But Grand Isle has been under water for hours.
Member Since: August 31, 2006 Posts: 0 Comments: 271
WOW 964MB
Member Since: Posts: Comments:
are there many homes in braithwaite LA?
Member Since: Posts: Comments:
Quoting WetBankGuy:
Been staring at Rainbow loop for a while and the old deep convection has died, but the convection patterns look much more organized, "tighter" around the center with new convection firing just NE of the COC. Little convection or radar return to the west of the storm still but there is a rain band trying to wrap around the center again.

Nice squall passing through New Orleans now, maybe some of those winds the flight found over Chandeleur Sound.




I think the stall may allow him to let go of some of his size (like he let go of that huge chunk of himself that went up the eastern seaboard a day or so ago....) and he can tighten up where he is....that is super hot water where he is and he isn't moving....we may see a well formed eyewall but much smaller than the large windfield eyewall we have been seeing....and if he does that he can RI very fast because his relative mb will try to catch him up with his relative CoC sustained winds and ramp up to a cat 2.....
Member Since: September 3, 2009 Posts: 0 Comments: 514
1112. jake436
Quoting FunhouseFX:


Not a deliberate joke, no. I am aware that there are some places that have had a lot of rain. Florida for example. But even many of the places sitting right under this thing's skirts often haven't gotten much in the way of rain.

The live cams and even TV reports have looked like nothing more than mild thunderstorm rain -- if that.

I think hurricane I think ten inches of rain. Fifteen.Particularly when you have been sitting under it for most of a most of a day. I don't think one or two inches.

So again, I was not joking. I am aware that despite the drama this is barely a hurricane at all, but this is one thing that has surprised me.
Again, you're looking at live shots from NOLA. NOLA is NOT on the coast. NOLA is not the center of the Hurricane Universe. Chalmette received over 4" of rain between 12 midnight and 2 pm. That's over 2"/hour. I would surmise from radar that it's probably up to 7" from midnight until 3am in Chalmette. Three hours. 7". That's not a lot of rain for a hurricane? FL got 15" of rain, but it wasn't in 6-8 hours.
Member Since: August 31, 2006 Posts: 0 Comments: 271
I decided t stuff in Slidel because I couldn't drive any furthe it just got too it just got too rough is is soon is t as I can get to a place to upload th
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1110. zillaTX
second landfall by TWC saying it will not make it back over water...
Member Since: Posts: Comments:
000
WTNT54 KNHC 290759
TCEAT4

HURRICANE ISAAC TROPICAL CYCLONE POSITION ESTIMATE
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
300 AM CDT WED AUG 29 2012

...CENTER OF ISAAC MAKES SECOND LANDFALL...

REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT AND NOAA RADAR
INDICATE THAT ISAAC MADE A SECOND LANDFALL ALONG THE COAST OF
SOUTHEAST LOUISIANA JUST WEST OF PORT FOURCHON AROUND 215 AM
CDT...0715 UTC...WITH MAXIMUM SUSTAINED WINDS OF 80 MPH...130 KM/H.

AT 300 AM CDT...0800 UTC...THE CENTER OF HURRICANE ISAAC WAS
ESTIMATED NEAR LATITUDE 29.2 NORTH...LONGITUDE 90.4 WEST...OR ABOUT
35 MILES SOUTH-SOUTHEAST OF HOUMA LOUISIANA...AND ABOUT 60 MILES
SOUTH-SOUTHWEST OF NEW ORLEANS LOUISIANA. ISAAC HAS BEGUN TO MOVE
WEST-NORTHWESTWARD NEAR 8 MPH...13 KM/H...AND A GENERAL
NORTHWESTWARD MOTION AT A SLOWER FORWARD SPEED IS EXPECTED LATER
TODAY.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Been staring at Rainbow loop for a while and the old deep convection has died, but the convection patterns look much more organized, "tighter" around the center with new convection firing just NE of the COC. Little convection or radar return to the west of the storm still but there is a rain band trying to wrap around the center again.

Nice squall passing through New Orleans now, maybe some of those winds the flight found over Chandeleur Sound.

Member Since: September 19, 2007 Posts: 0 Comments: 288
NDBC Summary at 3am CDT.

Grand Isle Buoy just got wind shift to south at 3:00am CDT. Storm surge should increase there now.

LINK


South of Ponchatrain buoy just recorded 63.9kt (73.5mph) winds from the ENE at 1:06am CDT

LINK


Shell Beach buoy recorded 68kt gust from the ENE at 10:30pm CDT

LINK


Eye passed directly over LOP1 station at 11:50am CDT with winds decreasing to 7kts, central pressure 28.59in or 968mb.

LINK


Seven consecutive hourly readings with sustained winds of 60mph or more from the north at buoy just south of Houma, Louisiana

LINK
Member Since: Posts: Comments:
Quoting jake436:
That's a joke, right? Chalmette received over 4" of rain between midnight and 2 am.


Not a deliberate joke, no. I am aware that there are some places that have had a lot of rain. Florida for example. But even many of the places sitting right under this thing's skirts often haven't gotten much in the way of rain.

The live cams and even TV reports have looked like nothing more than mild thunderstorm rain -- if that.

I think hurricane I think ten inches of rain. Fifteen.Particularly when you have been sitting under it for most of a most of a day. I don't think one or two inches.

So again, I was not joking. I am aware that despite the drama this is barely a hurricane at all, but this is one thing that has surprised me.
Member Since: April 11, 2009 Posts: 0 Comments: 18
Quoting jake436:
I know a lot of people on here actually live in LA, but most don't. I don't think those that don't understand fully the topography of the area this storm is currently situated. Here's the deal. You say the center is straddling land. No, it's really not. It may look like it on a map, but it's not. Take for instance the "land" between Golden Meadow and Grand Isle. It's a bridge, and a bunch of saltwater marsh with lakes and bays sprinkled in. That's not land. So you see the north end of the eye touching Golden Meadow, but that's not really "land" like you may think. It's not like MS or AL where there's a beach, then land. Anything south of I-10 in LA is wetlands. Either swamp or marsh. There's not much to disrupt the circulation, whether it looks like it on the map or not. That's why I thought it was silly to call that first "landfall" south of Venice. Where the first "landfall" occurred is literally nothing but water hyacinth and rip rap...Southwest Pass. There's no land there...no matter what the map shows.


Several years ago NOLA.com had an excellent interactive web story about this. The story baldly said that standard maps of Louisiana were "a lie". That these maps showed land where there was no land. The maps literally being used all the time are not accurate. The story also said LA is losing what amounts to a football field of land to the Gulf every 45 minutes. There was a shot of Golden Meadow taken in the 50's surrounded by land. A shot from several years ago shows an island town. There were many other specific instances like this one.
Member Since: October 14, 2008 Posts: 0 Comments: 179
1104. jake436
Quoting WetBankGuy:


Thank you. I suggest folks try flipping satellite on and off on Google maps for a bit to understand how much mapped "land" ain't dere no more.
It's not their fault...they can't possibly understand without seeing it for themselves. Just want people to realize the difference between LA and the surrounding states' topography. It's just different in LA. There isn't anywhere else around with the marsh system we have, and if they're familiar with TX marsh or MS/AL marsh or FL marsh, they think it's the same here. It's not. It's that multiplied by 100,000. The marsh doesn't end a few hundred yds from the Gulf here. It ends 100 MILES from the coast. One thing to draw a comparison to would be the Everglades in FL. Remember Katrina and Andrew both sustained or even gained strength crossing there. It's because there's not much land there. Same here, but even moreso.
Quoting FunhouseFX:
In my inexpert opinion it seems even the quantity of rain is unusually light for a storm like this.
That's a joke, right? Chalmette received over 4" of rain between midnight and 2 am.
Member Since: August 31, 2006 Posts: 0 Comments: 271
Quoting WetBankGuy:


Actual rainfall in the metro area from the Slidell radar, about 2.5". We can do that in an hour in a typical late summer afternoon thunderstorm. If it stalls and strengthens, that's another matter.



Lakefront Airport
has measured 5.49 inches so far, with 4.32 inches in the last 7 hours.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
What an amazing storm!! Throw the books away.....Isaac can't read!!
Member Since: Posts: Comments:
1101. FunhouseFX
7:48 AM GMT on August 29, 2012
In my inexpert opinion it seems even the quantity of rain is unusually light for a storm like this.
Member Since: April 11, 2009 Posts: 0 Comments: 18
1100. odinslightning
7:48 AM GMT on August 29, 2012
Quoting WetBankGuy:


Thank you. I suggest folks try flipping satellite on and off on Google maps for a bit to understand how much mapped "land" ain't dere no more.



it's a pity....when they channelled the Mississippi it sealed the fate of the bayou....but if they didn't tame the Mississippi New Orleans would have never been settled as much as it is now....so what can y'all do???

isn't it like an area the size of Manhattan is lost every year to the Gulf as the bayou melts away w/out the sediment deposit from the Miss??
Member Since: September 3, 2009 Posts: 0 Comments: 514
1099. WetBankGuy
7:45 AM GMT on August 29, 2012
Quoting jake436:
I know a lot of people on here actually live in LA, but most don't. I don't think those that don't understand fully the topography of the area this storm is currently situated. Here's the deal. You say the center is straddling land. No, it's really not. It may look like it on a map, but it's not. Take for instance the "land" between Golden Meadow and Grand Isle. It's a bridge, and a bunch of saltwater marsh with lakes and bays sprinkled in. That's not land. So you see the north end of the eye touching Golden Meadow, but that's not really "land" like you may think. It's not like MS or AL where there's a beach, then land. Anything south of I-10 in LA is wetlands. Either swamp or marsh. There's not much to disrupt the circulation, whether it looks like it on the map or not. That's why I thought it was silly to call that first "landfall" south of Venice. Where the first "landfall" occurred is literally nothing but water hyacinth and rip rap...Southwest Pass. There's no land there...no matter what the map shows.


Thank you. I suggest folks try flipping satellite on and off on Google maps for a bit to understand how much mapped "land" ain't dere no more.
Member Since: September 19, 2007 Posts: 0 Comments: 288
1098. jake436
7:44 AM GMT on August 29, 2012
Quoting atmosweather:


It's probably going to take a higher storm surge in addition to those 24 foot waves to do it...except if Isaac remains stalled south of New Orleans into tomorrow. Then the accumulating effect of the constant strong winds could churn up enough ocean and send it W-wards over the levees.

Regardless, the exceptional rain totals that Isaac will produce is going to be more than enough to cause a major flooding disaster in New Orleans and the rest of the Gulf coast states.
Those wave heights are in the Gulf. Not in Lake Ponchartrain. NOLA is nearly 100 miles from the Gulf.
Now the rain, the rain is another story. And the river topping levees, but that won't happen at NOLA either. That'll be well south of NOLA.
Member Since: August 31, 2006 Posts: 0 Comments: 271
1097. TexNowNM
7:44 AM GMT on August 29, 2012
Quoting dixiegal1:

We all have" paranoia " when it comes to these tropical storms and hurricanes. If you live close to the coast, you know every storm is unique in its own way. :). With that said , Texas is probably safe as far as landfall goes but as usual anything is possible with these storms.


You are right- every storm is unique. Our neighbors to the east have had experiences in the last few years I hope none of us ever see again. Stay safe!
Member Since: October 14, 2008 Posts: 0 Comments: 179
1096. odinslightning
7:43 AM GMT on August 29, 2012
Quoting jake436:
I know a lot of people on here actually live in LA, but most don't. I don't think those that don't understand fully the topography of the area this storm is currently situated. Here's the deal. You say the center is straddling land. No, it's really not. It may look like it on a map, but it's not. Take for instance the "land" between Golden Meadow and Grand Isle. It's a bridge, and a bunch of saltwater marsh with lakes and bays sprinkled in. That's not land. So you see the north end of the eye touching Golden Meadow, but that's not really "land" like you may think. It's not like MS or AL where there's a beach, then land. Anything south of I-10 in LA is wetlands. Either swamp or marsh. There's not much to disrupt the circulation, whether it looks like it on the map or not. That's why I thought it was silly to call that first "landfall" south of Venice. Where the first "landfall" occurred is literally nothing but water hyacinth and rip rap...Southwest Pass. There's no land there...no matter what the map shows.



i completely agree...in fact the water is hotter up in that area than in the gulf,.....it's very shallow water and is very warm....and even the shoreline is 1-2 degrees hotter than just 50 miles offshore.....the fetch to the south, the super hot water, and the stalling is allowing him to maintain and buys him time to tighten up his eyewall if that indeed is what is happening right now.......
Member Since: September 3, 2009 Posts: 0 Comments: 514
1095. atmosweather
7:42 AM GMT on August 29, 2012
Quoting SETXborda:
Looking at the satellite IR loop from NHC website and the eye is clearly seen offshore just rotating...I might be a novice, but it is clearly visible and is not ragged. Please correct me if I am wrong...just wanting to know...


Yes you are right, but onlyyy just since the center of Isaac's eye is no more than 10 miles offshore lol.

The radar view shows it well. It is perilously close to making official landfall.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1094. WetBankGuy
7:42 AM GMT on August 29, 2012
Quoting atmosweather:


It's probably going to take a higher storm surge in addition to those 24 foot waves to do it...except if Isaac remains stalled south of New Orleans into tomorrow. Then the accumulating effect of the constant strong winds could churn up enough ocean and send it W-wards over the levees.

Regardless, the exceptional rain totals that Isaac will produce is going to be more than enough to cause a major flooding disaster in New Orleans and the rest of the Gulf coast states.


Actual rainfall in the metro area from the Slidell radar, about 2.5". We can do that in an hour in a typical late summer afternoon thunderstorm. If it stalls and strengthens, that's another matter.
Member Since: September 19, 2007 Posts: 0 Comments: 288
1093. AussieStorm
7:41 AM GMT on August 29, 2012
Quoting AussieStorm:
Jennifer Hale @JenHale504
Plaquemines Parish releasing reverse 911 for Braithwaite residents: levee overtopping significantly on east bank. Residents must leave now.

Officers are going door to door in the area to evac people right now. Words from Jennifer Hale on Fox 8 New Orleans.

Link
Member Since: September 30, 2007 Posts: 9 Comments: 15979
1092. atmosweather
7:41 AM GMT on August 29, 2012
Oh boy...

073030 2911N 09014W 6975 02850 9647 +165 +088 193018 020 /// /// 03

Make that down 3 mb in less than 2 hours.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1091. dixiegal1
7:40 AM GMT on August 29, 2012
Quoting TexNowNM:


Yes, the term wish caster was thrown around quite liberally. I agree with the poster tonight who commented how much they appreciated the nonarguementive tone of the blog tonight and the lack of nit-picking over spelling. I don't know about other iPad user, but I find it hard to edit my work and check my spelling with these tiny little letters. Plus, you can't easily break into a sentence to correct something.


Yes, I don't understand the negative and argumentative tones in here a lot of times. DState your opinion, support it with data... Then who cares if someone else disagrees... Pay attention to their ideas and u might learn something you didn't know before. That's called a discussion. I've lurked for years but rarely post. Maybe that's why I have tonight a few times;). All I know is that sometimes people on this blog can be so right their wrong.. Know what I mean? It's always better to be kind than right:)
Member Since: August 26, 2006 Posts: 0 Comments: 77
1090. SETXborda
7:40 AM GMT on August 29, 2012
Looking at the satellite IR loop from NHC website and the eye is clearly seen offshore just rotating...I might be a novice, but it is clearly visible and is not ragged. Please correct me if I am wrong...just wanting to know...
Member Since: September 2, 2011 Posts: 0 Comments: 7
1089. jake436
7:39 AM GMT on August 29, 2012
I know a lot of people on here actually live in LA, but most don't. I don't think those that don't understand fully the topography of the area this storm is currently situated. Here's the deal. You say the center is straddling land. No, it's really not. It may look like it on a map, but it's not. Take for instance the "land" between Golden Meadow and Grand Isle. It's a bridge, and a bunch of saltwater marsh with lakes and bays sprinkled in. That's not land. So you see the north end of the eye touching Golden Meadow, but that's not really "land" like you may think. It's not like MS or AL where there's a beach, then land. Anything south of I-10 in LA is wetlands. Either swamp or marsh. There's not much to disrupt the circulation, whether it looks like it on the map or not. That's why I thought it was silly to call that first "landfall" south of Venice. Where the first "landfall" occurred is literally nothing but water hyacinth and rip rap...Southwest Pass. There's no land there...no matter what the map shows.
Member Since: August 31, 2006 Posts: 0 Comments: 271
1088. odinslightning
7:39 AM GMT on August 29, 2012
Quoting atmosweather:
Another mb drop in pressure as RECON hits the center again:

07:27:00Z
29.133N 90.383W
697.0 mb (~ 20.58 inHg)
2,883 meters (~ 9,459 feet)
966.9 mb (~ 28.55 inHg)



land shear may be causing shrinkage of the storm, thus allowing Isaac to pull in tighter....the deep moisture to the south is also allowing him to drink higher octane fuel....and he isn't gonna be moving anytime soon....
Member Since: September 3, 2009 Posts: 0 Comments: 514
1087. WetBankGuy
7:38 AM GMT on August 29, 2012
Quoting DataNerd:
Recent observed winds occurring well inland in LA east of NOLA

Time: 01:46:30Z
Coordinates: 29.5333N 89.1W
Acft. Static Air Press: 843.0 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,383 meters (~ 4,537 feet)
Extrap. Sfc. Press: 988.3 mb (~ 29.18 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 121° at 80 knots (From the ESE at ~ 92.0 mph)
Air Temp: 17.4°C (~ 63.3°F)
Dew Pt: 15.5°C (~ 59.9°F)
Peak (10s) Flt. Lvl. Wind: 80 knots (~ 92.0 mph)
SFMR Peak (10s) Sfc. Wind: 59 knots (~ 67.8 mph)
SFMR Rain Rate: 4 mm/hr (~ 0.16 in/hr



So the nasty winds are already ashore and blasting through, gusts are probably in the high 70-s to mid 80s right now. Not as bad as ike but quite bad because the storm is basically not moving.


Those coordinates are in Chandeleur Sound at the mostly historical tip of whats left of the Chandeleur Islands. That's right in the middle of the feeder bands that are wrapping over the city but I haven't seen a station record a gust on land over 65 kts.

Member Since: September 19, 2007 Posts: 0 Comments: 288
1086. atmosweather
7:38 AM GMT on August 29, 2012
Quoting AussieStorm:
Jennifer Hale ‏@JenHale504
Plaquemines Parish releasing reverse 911 for Braithwaite residents: levee overtopping significantly on east bank. Residents must leave now.


Well there's our answer...what a terrible night.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1085. AussieStorm
7:38 AM GMT on August 29, 2012
Jennifer Hale ‏@JenHale504
Plaquemines Parish releasing reverse 911 for Braithwaite residents: levee overtopping significantly on east bank. Residents must leave now.
Member Since: September 30, 2007 Posts: 9 Comments: 15979
1084. atmosweather
7:37 AM GMT on August 29, 2012
Another mb drop in pressure as RECON hits the center again:

07:27:00Z
29.133N 90.383W
697.0 mb (~ 20.58 inHg)
2,883 meters (~ 9,459 feet)
966.9 mb (~ 28.55 inHg)
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1083. WetBankGuy
7:36 AM GMT on August 29, 2012
Quoting kctinney:
Is anyone concerned about the new levees being breached in NO considering waves noted at one buoy at 24ft, wind and rain for the next approx 24-36 hours in the same area?


Not unless they've installed a new buoy in Lake Pontchartrain I don't know about. The city's levees don't fact the sea. Yet.

Member Since: September 19, 2007 Posts: 0 Comments: 288
1082. odinslightning
7:35 AM GMT on August 29, 2012
Quoting TexNowNM:


Yes, the term wish caster was thrown around quite liberally. I agree with the poster tonight who commented how much they appreciated the nonarguementive tone of the blog tonight and the lack of nit-picking over spelling. I don't know about other iPad user, but I find it hard to edit my work and check my spelling with these tiny little letters. Plus, you can't easily break into a sentence to correct something.


i think we had an initial rush of bloggers who came here to make problems since TWC started to advertise Weather Underground while Isaac was forming.....I hope they got bored with our boring science and meteorological terms that they couldnt understand and they left....lol
Member Since: September 3, 2009 Posts: 0 Comments: 514
1081. kctinney
7:34 AM GMT on August 29, 2012
Quoting odinslightning:



agreed, and what i know about property damage how can they arbitrarily say the damage will be x at y wind speed? how do you attribute for water shearing in at an angle blowing in and around corners, nooks, and crannies on every structure that isn't designed to take huge water in certain directions? and how do you figure that x property damage will occur at y wind speed because some storms are dry, some are very wet, some move very slow and cause other things to happen, like felled trees/tree branches......the system does need to be updated, but with care and patience :)

they have come a long way in 20+ yrs though, you gotta admit....from Andrew to now....to be able to call this storm this many days out this correctly????....wow....


Oh definately, but I think the true lay person would better understand the magnitude of a storm if even relayed as I said, rather than many assuming this is just a typical low CAT 1
Member Since: August 18, 2009 Posts: 0 Comments: 44
1080. atmosweather
7:33 AM GMT on August 29, 2012
Quoting kctinney:
Is anyone concerned about the new levees being breached in NO considering waves noted at one buoy at 24ft, wind and rain for the next approx 24-36 hours in the same area?


It's probably going to take a higher storm surge in addition to those 24 foot waves to do it...except if Isaac remains stalled south of New Orleans into tomorrow. Then the accumulating effect of the constant strong winds could churn up enough ocean and send it W-wards over the levees.

Regardless, the exceptional rain totals that Isaac will produce is going to be more than enough to cause a major flooding disaster in New Orleans and the rest of the Gulf coast states.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1079. TexNowNM
7:33 AM GMT on August 29, 2012
Quoting HoustonTxGal:


I agree 100% a few days ago anyone from TX even hinted at it coming to TX was labeled a wishcater etc etc etc. I have been hit by these things to may times and I in no way WISH for one to come my way. I just know how fickle they are and how many times TX had been hit by storms that were not suppose to head it's way.


Yes, the term wish caster was thrown around quite liberally. I agree with the poster tonight who commented how much they appreciated the nonarguementive tone of the blog tonight and the lack of nit-picking over spelling. I don't know about other iPad user, but I find it hard to edit my work and check my spelling with these tiny little letters. Plus, you can't easily break into a sentence to correct something.
Member Since: October 14, 2008 Posts: 0 Comments: 179
1078. kctinney
7:29 AM GMT on August 29, 2012
Is anyone concerned about the new levees being breached in NO considering waves noted at one buoy at 24ft, wind and rain for the next approx 24-36 hours in the same area?
Member Since: August 18, 2009 Posts: 0 Comments: 44
1077. srqthymesage
7:29 AM GMT on August 29, 2012
Quoting misscoast:

I am in Gulfport and live just a couple hundred yards from the Bayou and I am 1-1/2 miles from beach. We have had somes winds but the surge has been pretty bad in the Bayou's, especially in the area I live in.


oops, I wasn't clear...i read further and found that 'moving left' means northeast. I'm in Florida. Sorry you're water up to ....? Godspeed for you and yours.
Member Since: August 17, 2012 Posts: 0 Comments: 86
1076. odinslightning
7:28 AM GMT on August 29, 2012
Quoting kctinney:
Category One Hurricane
•Maximum Sustained Wind Speed: 74-95 miles per hour
•Damage Category: Minimal
•Approximate Pressure: Above 980 mb
•Approximate Storm Surge: 3-5 feet
•Examples: Hurricane Lili (2002) in Louisiana; Hurricane Gaston (2004) in South Carolina

Category Two Hurricane
•Maximum Sustained Wind Speed: 96-110 miles per hour
•Damage Category: Moderate
•Approximate Pressure: 979-965 mb
•Approximate Storm Surge: 6-8 feet
•Example: Hurricane Isabel (2003) in North Carolina

Category Three Hurricane
•Maximum Sustained Wind Speed: 111-129 miles per hour
•Damage Category: Extensive
•Approximate Pressure: 964-945 mb
Approximate Storm Surge: 9-12 feet
•Examples: Hurricane Katrina (2005) in Louisiana; Hurricane Jeanne (2004) in Florida; Hurricane Ivan (2004) in Alabama

Category Four Hurricane
•Maximum Sustained Wind Speed: 130-156 miles per hour
•Damage Category: Extreme
•Approximate Pressure: 944-920 mb
•Approximate Storm Surge: 13-18 feet
•Example: Hurricane Charley (2004) in Florida; Hurricane Iniki (1992) in Hawaii; the Galveston Hurricane (1900) in Texas

Category Five Hurricane
•Maximum Sustained Wind Speed: 157 miles per hour and higher
•Damage Category: Catastrophic
•Approximate Pressure: Below 920 mb
•Approximate Storm Surge: More than 18 feet
•Examples: Only three Category 5 hurricanes have struck the United States since records began: The Labor Day Hurricane (1935) in the Florida Keyes, Hurricane Camille (1969) near the mouth of the Mississippi River, and Hurricane Andrew (1992) in Florida

So we have a CAT 1 Hurricane wind speed, CAT 2 (getting close to CAT 3) in mb and CAT 3 in Storm Surge

They REALLY need to revamp this system based on more factors such as size.



agreed, and what i know about property damage how can they arbitrarily say the damage will be x at y wind speed? how do you attribute for water shearing in at an angle blowing in and around corners, nooks, and crannies on every structure that isn't designed to take huge water in certain directions? and how do you figure that x property damage will occur at y wind speed because some storms are dry, some are very wet, some move very slow and cause other things to happen, like felled trees/tree branches......the system does need to be updated, but with care and patience :)

they have come a long way in 20+ yrs though, you gotta admit....from Andrew to now....to be able to call this storm this many days out this correctly????....wow....
Member Since: September 3, 2009 Posts: 0 Comments: 514
1075. atmosweather
7:26 AM GMT on August 29, 2012
What an unbelievable storm this has become. And a sad sight to behold when you realize the kind of damage this is doing to property and lives.

968 mb after straddling the coast for 9 hours. The conditions were almost perfect aloft, and dry air had been combated. If Isaac were given 6-12 more hours over the north central Gulf of Mexico today, he would have done what THAT storm did 7 years ago to the day. As it is, this is going to reach close to or pass the Category 1 record 16 billion dollars of damage done by Irene in 2011.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1074. misscoast
7:25 AM GMT on August 29, 2012
Quoting canehater1:


Hurricanes want to go poleward (North) The turn to the right (Northeast) is due to Coriolis Force, The rotation of the Earth, and inducement by troughs and ridges


I lived in Gulfport during Hurrican Elana. If you ever get a chance look at her path. Was very strange because it was headed toward the Miss. Coast the stalled, the went to Florida East Coast and did a 360 and came back and made landfall in Mississippi. Was really strange.
Member Since: July 23, 2008 Posts: 0 Comments: 25
1073. dixiegal1
7:25 AM GMT on August 29, 2012
Quoting TexNowNM:


I know some don't get our "paranoia" but that is because SE Texas has had such unique experiences. Allison was just a tropical storm but killed so many people and caused over a billion in damage, Rita was not supposed to hit here but did, Humberto became a hurricane literally overnight but wasn't supposed to, and Ike wasn't supposed to be ours either. Our experience has been things change dramatically in a matter of hours.

I remember last week when anyone who suggested Isaac would go west of Florida was dealt with rather harshly by some. Now look where we are.


We all have" paranoia " when it comes to these tropical storms and hurricanes. If you live close to the coast, you know every storm is unique in its own way. :). With that said , Texas is probably safe as far as landfall goes but as usual anything is possible with these storms.
Member Since: August 26, 2006 Posts: 0 Comments: 77
1072. odinslightning
7:25 AM GMT on August 29, 2012
Quoting wxchaser97:
New convection burst, I'm now really going to bed.


thats what they were saying on n.o. weather, the land shear is forcing this to tighten up....it is encouraging him to constrict and pull in, which will speed up the CoC wind speed....but the fetch is so deep from the south this is gonna wrap again and it may strengthen in the next 2-3 hrs....
Member Since: September 3, 2009 Posts: 0 Comments: 514
1071. HoustonTxGal
7:23 AM GMT on August 29, 2012
Quoting TexNowNM:


I know some don't get our "paranoia" but that is because SE Texas has had such unique experiences. Allison was just a tropical storm but killed so many people and caused over a billion in damage, Rita was not supposed to hit here but did, Humberto became a hurricane literally overnight but wasn't supposed to, and Ike wasn't supposed to be ours either. Our experience has been things change dramatically in a matter of hours.

I remember last week when anyone who suggested Isaac would go west of Florida was dealt with rather harshly by some. Now look where we are.



I agree 100% a few days ago anyone from TX even hinted at it coming to TX was labeled a wishcater etc etc etc. I have been hit by these things to may times and I in no way WISH for one to come my way. I just know how fickle they are and how many times TX had been hit by storms that were not suppose to head it's way.
Member Since: September 18, 2007 Posts: 0 Comments: 1074
1070. jpsb
7:23 AM GMT on August 29, 2012
Nice strong breeze out of the north here on Galveston Bay.
Member Since: June 30, 2009 Posts: 0 Comments: 1276
1069. kctinney
7:23 AM GMT on August 29, 2012
Category One Hurricane
%u2022Maximum Sustained Wind Speed: 74-95 miles per hour
%u2022Damage Category: Minimal
%u2022Approximate Pressure: Above 980 mb
%u2022Approximate Storm Surge: 3-5 feet
%u2022Examples: Hurricane Lili (2002) in Louisiana; Hurricane Gaston (2004) in South Carolina

Category Two Hurricane
%u2022Maximum Sustained Wind Speed: 96-110 miles per hour
%u2022Damage Category: Moderate
%u2022Approximate Pressure: 979-965 mb
%u2022Approximate Storm Surge: 6-8 feet
%u2022Example: Hurricane Isabel (2003) in North Carolina

Category Three Hurricane
%u2022Maximum Sustained Wind Speed: 111-129 miles per hour
%u2022Damage Category: Extensive
%u2022Approximate Pressure: 964-945 mb
%u2022Approximate Storm Surge: 9-12 feet
%u2022Examples: Hurricane Katrina (2005) in Louisiana; Hurricane Jeanne (2004) in Florida; Hurricane Ivan (2004) in Alabama

Category Four Hurricane
%u2022Maximum Sustained Wind Speed: 130-156 miles per hour
%u2022Damage Category: Extreme
%u2022Approximate Pressure: 944-920 mb
%u2022Approximate Storm Surge: 13-18 feet
%u2022Example: Hurricane Charley (2004) in Florida; Hurricane Iniki (1992) in Hawaii; the Galveston Hurricane (1900) in Texas

Category Five Hurricane
%u2022Maximum Sustained Wind Speed: 157 miles per hour and higher
%u2022Damage Category: Catastrophic
%u2022Approximate Pressure: Below 920 mb
%u2022Approximate Storm Surge: More than 18 feet
%u2022Examples: Only three Category 5 hurricanes have struck the United States since records began: The Labor Day Hurricane (1935) in the Florida Keyes, Hurricane Camille (1969) near the mouth of the Mississippi River, and Hurricane Andrew (1992) in Florida

So we have a CAT 1 Hurricane wind speed, CAT 2 (getting close to CAT 3) in mb and CAT 3 in Storm Surge

They REALLY need to revamp this system based on more factors such as size.
Member Since: August 18, 2009 Posts: 0 Comments: 44

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