Hurricane Gustav Pt II

[londonsnow]

thanks guys. bush and mcain seem to be getting into the spotlight on this. as yet no sign of obama. maybe he's waiting, but he should from a political perspective be getting his act together fast

[sabrewulf]

Convection bursting in the Northern eyewall now, overshadowing the eye, I think we may well see the eye try and emerge again.

The thing to note whilst heat content is low the fast foward speed will allow for it not to matter, Felix went over similar heat content at its peak and that didn't stop it...

Shear seems to be easing very quickly off, the system getting symmetric and bursting eyewall is strongly suggestive of a strengthening hurricane, we shall have to wait and see but this is the WORST possible situation for LA and N.O sadly, a system that is strengthening. Wind damage to N.O will be more severe than with Katrina.

is it a reasonable guess that this thing is INCREASING in strength right before landfall?

if thats the case , thats WAY different to katrina - which decreased in strength before hitting land.

[Paranoid]

What sort of increase in strength are we looking at? Hopefully it wont be too much considering it's close to landfall as it is.

[SMU]

is it a reasonable guess that this thing is INCREASING in strength right before landfall?

if thats the case , thats WAY different to katrina - which decreased in strength before hitting land.

The further it strengthens the lesser effect the the westerly steering winds will have.........

S

[sabrewulf]

thanks guys. bush and mcain seem to be getting into the spotlight on this. as yet no sign of obama. maybe he's waiting, but he should from a political perspective be getting his act together fast

ack.. i knew somebody would raise this eventually. look, i'm on the mccain side poliitically, but this is very difficult for obama - if he turned up down there, then it would backfire as taking advantage out of a potential disaster for political ends.

he's doing the right thing by staying out of it and not turning it into a political issue. this affects everyone down there.

he's doing the right thing - and just letting the folks that actually run the government right now to do their jobs.

to be honest - all the politicians in that neck of the woods seem to have put their differences aside and just worked at getting folks the hell out of there and to safety.

the governor of louisiana - bobby jindal is a republican - but the mayor of NO is democrat...

political point scoring over this is not needed. and my reading of it is that all sides recognise this.

APOLOGIES: to the purist weather posters as this post has nothing to do with weather. but you cant avoid the human aspect of this. just thought i'd throw my thoughts into the mix. hope you folks dont mind.

Edited August 31, 2008 by sabrewulf

[Roger J Smith]

Let's qualify that by saying this is a somewhat negative turn of events in the range of what's possible from this hurricane, by no means is this now or predicted to be the worst case scenario for New Orleans. The situation is best described as very similar to what I was saying 36 hours ago, or so, that New Orleans is on the cusp between just avoiding major damage and getting localized major damage mainly from flooding, the wind damage potential for the city appears to be no worse than cat-1 and this should be scattered minor wind damage at worst.

The dangerous places to be tomorrow would be Grand Isle to Houma and over towards the far western suburban area around New Orleans perhaps, but also west towards Morgan City and New Iberia. Grand Isle is pretty much the only large built up area near predicted landfall (which I'm thinking will be 15z Monday) but it is largely evacuated according to an on-the-spot CNN reporter. Between there and Houma is mainly swamp and bayou although there are a few agricultural areas and small towns just southeast of Houma (which is a mid-sized town not a huge place either). No huge storm surge can make it this far through all the swamps and bayous but of course the waters could rise by several feet, however the damage from wind could be significant at about cat-2 intensity (Grand Isle could get whatever the max of this landfalling storm has to offer, possibly low-end cat 4?) ...

So, the bottom line is, New Orleans is by no means doomed here, but nobody is breathing any sigh of relief either, in fact the official track from quite a while back is verifying quite well, the intensity has lagged a little but could catch up by 03-06z and peak around low end cat 4.

My (admitted) guess is that New Orleans and immediate surroundings will come through this with some damage from flooding, a bit of wind damage, but not a major disaster, and it will be a matter of days rather than weeks before things return to normal. Houma might need two or three weeks to recover. It will be bad there but not as bad as Katrina's landfall in MS three years ago. Let's hope this is right because these people have been through enough already.

[kold weather]

Its possible this will strengthen to a secondary peak just before it makes landfall then level out about 50 miles before making landfall. Its got about aanother 12hrs before landfall based on current foward motion.

As i said heat content isn't aamzing but this system will only need the surface heat given its foward speed is pretty rapid and thats plenty warm for a cat-3 to strengthen in.

IR showing cloud tops cooling down and convection deepening, whilst there on the SE side of the eye cloud tops are warming...meaning the eye is about to pop back out again probably once this big burst is eased out of the way...

Roger, watch the system jog east of mean motion within the last few hours before landfall, I think this will go right over N.O right now but I hope I'm wrong.

Edited August 31, 2008 by kold weather

[SMU]

Let's qualify that by saying this is a somewhat negative turn of events in the range of what's possible from this hurricane, by no means is this now or predicted to be the worst case scenario for New Orleans. The situation is best described as very similar to what I was saying 36 hours ago, or so, that New Orleans is on the cusp between just avoiding major damage and getting localized major damage mainly from flooding, the wind damage potential for the city appears to be no worse than cat-1 and this should be scattered minor wind damage at worst.

The dangerous places to be tomorrow would be Grand Isle to Houma and over towards the far western suburban area around New Orleans perhaps, but also west towards Morgan City and New Iberia. Grand Isle is pretty much the only large built up area near predicted landfall (which I'm thinking will be 15z Monday) but it is largely evacuated according to an on-the-spot CNN reporter. Between there and Houma is mainly swamp and bayou although there are a few agricultural areas and small towns just southeast of Houma (which is a mid-sized town not a huge place either). No huge storm surge can make it this far through all the swamps and bayous but of course the waters could rise by several feet, however the damage from wind could be significant at about cat-2 intensity (Grand Isle could get whatever the max of this landfalling storm has to offer, possibly low-end cat 4?) ...

So, the bottom line is, New Orleans is by no means doomed here, but nobody is breathing any sigh of relief either, in fact the official track from quite a while back is verifying quite well, the intensity has lagged a little but could catch up by 03-06z and peak around low end cat 4.

My (admitted) guess is that New Orleans and immediate surroundings will come through this with some damage from flooding, a bit of wind damage, but not a major disaster, and it will be a matter of days rather than weeks before things return to normal. Houma might need two or three weeks to recover. It will be bad there but not as bad as Katrina's landfall in MS three years ago. Let's hope this is right because these people have been through enough already.

Good post Roger- although your basing your assumptions on the model guidence-

The latest IR data is 'suggesting' that the eye is already NE of guidence & possible set to jog further N & E....

If the coldest cloud tops get all the way round the system & we maintain a RI phase then this is entirely possible-

Although if I doesnt happen then a track towards Houma will have less of an effect..

awaiting VDM message-

000

URNT12 KNHC 312320

VORTEX DATA MESSAGE AL072008

A. 31/23:03:00Z

B. 26 deg 43 min N

087 deg 29 min W

C. 700 mb 2701 m

D. 78 kt

E. 270 deg 9 nm

F. 053 deg 079 kt

G. 302 deg 055 nm

H. 953 mbI. 7 C/ 3059 m

J. 17 C/ 3038 m

K. 8 C/ NA

L. CLOSED

M. E33/40/25

N. 12345/7

O. 0.02 / 2 nm

P. AF304 2207A GUSTAV OB 21

MAX FL WIND 97 KT NE QUAD 21:00:30 Z

MAX OUTBOUND FL WND 90 KT SE QUAD 23:08:20 Z

10c on the thermal gradient now..........

wow- its getting very symetrical-

here

Roger:

VDM fix is east of Model Guidence:-

http://www.gscape.com/images/wx/gustavrecon310808_04.jpg

S

Edited August 31, 2008 by Steve Murr

[PersianPaladin]

Persian Paladin: I think it was in Bay St Louis.

Edit: Found a reference http://en.wikipedia.org/wiki/Bay_St_Louis#Hurricane_Katrina

In my experience, one should never use wikipedia as a reference for anything. Its just misleading and innacurate. The only reference to "30 feet" here is the rather dubious: -

^ "Hurricane Katrina Related Damages to Public Libraries in Mississippi" (September 2005), Mississippi Library Commission, (ALA-Katrina).

I'd go with the 18 feet max which other users had quoted.

With regards to Gustav; I think the time for significant strengthening very much depends on what Steve Murr has said. The strength and vertical shear profile of upper winds will of course influence the degree of convective organisation and the speed in which the hurricane moves. It doesnt help though the centre of the vortex has moved into cooler waters; albeit temp gradients are assisting certain quadrants of the vortex to be pepped-up with notable towers and this is likely helping to rejuvenize eye-formation even though 'seeing' a clear-eye isn't neccessarily an absolute requirement.

I'd go with a weak Cat 4 as Roger has suggested. All predictions of a category 5 by news-agencies like Sky, etc have been wrong, and always unlikely since the hurricane crossed western Cuba; in my opinion.

Edited August 31, 2008 by PersianPaladin

[kold weather]

Indeed Steve I think a study found 75% of all systems take a motion east of the previous 12-24hrs motion, thats a big percentage that do that and obviously a 30-40 mile shift east will cause severe issues for N.O and possibly severe flooding issues.

I also think Steve that this is strengthening, not sure if heat content is high enough for RI but I've got no doubt this is certainly undergoing at least moderate speed deepening.

Winds at flight level now high enough to possibly support winds being upped to 105kts now and pressure is dropping away, probably wil lget into then 940's before landfall.

[Roger J Smith]

I should add I am basing my assumptions on model guidance and my own estimate of likely track. I do see signs of intensification at the moment and my predicted track is landfall 30 miles west of Grand Isle (land is a relative concept if you look at google earth for the area, the outer limit of swamp perhaps) then just west of Houma. I don't see too much risk of a last-minute swerve towards New Orleans, if that happens though, it will be game over for sure.

I reserve the right to change my mind on that after seeing the 00z upper air at 0215-0230z. Once these storms get embedded under a 500-mb closed low they almost always stay near that feature and the models are usually quite accurate on 12 and 24 hour positions of such features, so this is perhaps why I feel a bit more confident than if this were one of those hurricanes embedded in a southerly flow that has more chance of jogging off course.

The other caution is that New Orleans is under two different sorts of flood risk here, one is the direct threat from storm surge into the main levee band to the south, the other is some sort of eventual overtopping from confluence of all sorts of minor regional water rises through the complicated drainage to the west of the Mississippi. All of this is pretty complicated to predict but those who are on the spot doing that (core of engineers, local hydromet) seem to be cautiously optimistic at this time.

However, I remember that we thought New Orleans had made it through Katrina until the water breached the north-side levee almost 24 hours after the eye went past into MS, so it remains probably just too close to call -- which is a whole lot better than the situation for the MS coast at 24 hours before landfall where one could foresee with high probability a large-scale disaster. By the way, sure Katrina was weakening as it approached, but it was weakening from a low-end cat-5 and I think radar was still characteristic of a cat-4 storm near Bay St Louis, also there was a tremendous swath of tornadic enhanced winds through that region, so when we say "weakening" it is perhaps only weaker than Camille which is not saying anything really. Camille was probably the all-time monster hurricane.

One sobering postscript, the Galveston hurricane of 1900 was probably at about this strength before hitting the coast, so much depends on the combination of wind, surge and topography, it doesn't take a worst-case deepening to bring about a large disaster.

[SMU]

I should add I am basing my assumptions on model guidance and my own estimate of likely track. I do see signs of intensification at the moment and my predicted track is landfall 30 miles west of Grand Isle (land is a relative concept if you look at google earth for the area, the outer limit of swamp perhaps) then just west of Houma. I don't see too much risk of a last-minute swerve towards New Orleans, if that happens though, it will be game over for sure.

I reserve the right to change my mind on that after seeing the 00z upper air at 0215-0230z. Once these storms get embedded under a 500-mb closed low they almost always stay near that feature and the models are usually quite accurate on 12 and 24 hour positions of such features, so this is perhaps why I feel a bit more confident than if this were one of those hurricanes embedded in a southerly flow that has more chance of jogging off course.

The other caution is that New Orleans is under two different sorts of flood risk here, one is the direct threat from storm surge into the main levee band to the south, the other is some sort of eventual overtopping from confluence of all sorts of minor regional water rises through the complicated drainage to the west of the Mississippi. All of this is pretty complicated to predict but those who are on the spot doing that (core of engineers, local hydromet) seem to be cautiously optimistic at this time.

However, I remember that we thought New Orleans had made it through Katrina until the water breached the north-side levee almost 24 hours after the eye went past into MS, so it remains probably just too close to call -- which is a whole lot better than the situation for the MS coast at 24 hours before landfall where one could foresee with high probability a large-scale disaster. By the way, sure Katrina was weakening as it approached, but it was weakening from a low-end cat-5 and I think radar was still characteristic of a cat-4 storm near Bay St Louis, also there was a tremendous swath of tornadic enhanced winds through that region, so when we say "weakening" it is perhaps only weaker than Camille which is not saying anything really. Camille was probably the all-time monster hurricane.

One sobering postscript, the Galveston hurricane of 1900 was probably at about this strength before hitting the coast, so much depends on the combination of wind, surge and topography, it doesn't take a worst-case deepening to bring about a large disaster.

Hi Roger,

A couple of more bits yoyu have not read-

This is the VDM Position- East of Guidence-

Also-

The last recon is down to 951 MB- thats a 5mb drop in the hour-

Also-

The thermal gradient has gone up by 8c in 2 hours-

The 18z HWFR- Has it @ 940 landfall-

http://raleighwx.easternuswx.com/models/hw...MSLnest2024.gif

Although this was initialised before that Easterly VDM fix

The forward motion is down to 15mph-

Here is the IR position V model guidence-

http://raleighwx.easternuswx.com/models/sa...atatcfzoom.html

One for us all to monitor:-

S

Edited August 31, 2008 by Steve Murr

[kaz]

watching CNN and it looks like the outa bands have already started to make there impact felt.. What surprises me is they seemed shocked about this. is this because it was going so fast across the gulf before it started to slow?

kaz

[SMU]

THIS IS VERY VERY CONCERNING-

Here is the extrap 3 hour track ( from eaus)

4pm 26.4N 87.3W

7pm 26.9N 87.7W

5 units north and 4 west

that mean on the same track it will be-

10pm ( ET) 27.4 N 88.1 W

1am ET 27.9 N 88.5 W

4am ET 28.4N 88.9 W

7am ET 28.9N 89.3 W

10am ET 29.4N 89.7 W

1pm ET 29.9N 90.1 W DIRECT NOLA HIT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Downtown NO Is-

http://www.traveljournals.net/explore/unit...ew_orleans.html

locale is-

Latitude:

29.9546482 N

Longitude:

-90.075072 W

We are also now below 950MB

S

Edited September 1, 2008 by Steve Murr

[kold weather]

Indeed Steve motion has turned close to NNW over the last 2hrs according to recon, I think this is the easterly motion relative that I was mentioning. I still think it will go a touch west of N.O but we shall have to see, either way they will get sustained hurricane force winds, the high skyscrapers will probably get gusts upwards of 140mph probably at the top...expect to see shattered glass and windows after all is said and done...and sadly probably an awful lot more damage then that as well.

Pressure dropped to 949mbs, pretty quick pressure drop but I stil think it will only steadily strengthen from now on in afte rhte intial thrust downwards with the cold cloud tops in the eyewall developing.

[Paranoid]

How long do we have before landfall? 8 or so hours? If it keeps strengthening at the current rate (which it may well do for the next 4 or so hours before the inner sections of the storm start to interact with land), what sort of landfall pressure will we be looking at?

Edited September 1, 2008 by Paranoid

[SMU]

How long do we have before landfall? 8 or so hours? If it keeps strengthening at the current rate (which it may well do for the next 4 or so hours before it starts to interact with land), what sort of landfall pressure will we be looking at?

I would go for a central pressure peak in intensity of between 935 & 940 Mb-

Surface winds will probably fall into the catagory of high end cat 3- low end cat 4

Almost perfect symmetry now

HERE

If you see the convection ( the white pixelated bits) get all the way round that eye then it will carry on intensifying at a rapid rate-

The eastern end isnt quite there yet with pockets of dry air intrusion...

S

Edited September 1, 2008 by Steve Murr

[PersianPaladin]

UPDATE

Netweather.tv just got a mention on WIBR-FM in Louisana.

Edited September 1, 2008 by PersianPaladin

[PersianPaladin]

Tornado spawned in Livingston Parish.

No major damage reported as of yet.

[Roger J Smith]

You may already have this link for coastal buoys near the track:

http://www.ndbc.noaa.gov/maps/WestGulf_inset.shtml

I will post a radar link next (again, won't be new to most).

Radar link

http://www.weatherimages.org/radar/klix.shtml

[androcles]

This is interesting...

http://www.usatoday.com/weather/storms/hur...ne-hunter_N.htm

[Mondy]

http://radar.weather.gov/ridge/radar_lite....0Z&loop=yes

[opplevelse]

Good morning all!

Well the open eye everyone "saw" last night failed to emerge (I wont say I told you so but ... ok .. I will LOL ).

Gustav is still looking horrible in terms of organisation with poor internal structure.

A direct hit on NOLA will actually be a little nicer as it will limit the storm surge (Which will be greatest on the Eastern flank)

[Iceberg]

The eye is getting closer.

I have to admit despite all the talk of strengthening The highest flight winds he has recorded at 118Kt making a 105Kt storm at max, this is despite Recon crawling all over him. This is just a CAT 3 he's probably at 100Kt's now.

His presentation is better, but there is not much evidence of strengthening.

The Vortexes for the last 24 hrs are below.

26 AF 09/01 04:40:50Z 955mb (~28.20 inHg) 77kts

(~88.5mph) - 66kts

(~75.9mph)

24 NOAA 09/01 02:03Z 955mb (~28.20 inHg) 113kts

(~129.9mph) 113kts

(~129.9mph) 85kts

(~97.7mph)

22 AF 08/31 23:03:00Z 953mb (~28.14 inHg) 105kts

(~120.7mph) 105kts

(~120.7mph) 93kts

(~106.9mph)

20 NOAA 08/31 13:48Z 962mb (~28.41 inHg) 71kts

(~81.6mph) 71kts

(~81.6mph) 76kts

(~87.4mph)

18 AF 08/31 11:03:10Z 959mb (~28.32 inHg) 113kts

(~129.9mph) 118kts

(~135.7mph) 98kts

(~112.7mph

26 AF 09/01 04:40:50Z 955mb (~28.20 inHg) 77kts

(~88.5mph) - 66kts

(~75.9mph)

24 NOAA 09/01 02:03Z 955mb (~28.20 inHg) 113kts

(~129.9mph) 113kts

(~129.9mph) 85kts

(~97.7mph)

22 AF 08/31 23:03:00Z 953mb (~28.14 inHg) 105kts

(~120.7mph) 105kts

(~120.7mph) 93kts

(~106.9mph)

20 NOAA 08/31 13:48Z 962mb (~28.41 inHg) 71kts

(~81.6mph) 71kts

(~81.6mph) 76kts

(~87.4mph)

18 AF 08/31 11:03:10Z 959mb (~28.32 inHg) 113kts

(~129.9mph) 118kts

(~135.7mph) 98kts

(~112.7mph

2 Mins ago the lowest pressure currently being recorded is 954mb

This is all very good news for LA and New Orleans. Less good news is the track which brings him much closer to NO, I'd suggest maybe 20-30 miles west, Another good call from the models which have been predicting this for days now.

[Roger J Smith]

Words can mean different things to different readers, but if we are talking about the track of the centre of Gustav it has not deviated from the track discussed earlier, it is not on some course towards making a direct hit on New Orleans and the closest the centre will come to the city is about 70-100 miles at landfall, after which it will be heading more WNW than NW and away from the city.

The situation remains exactly the same as discussed earlier, a glancing blow with significant storm surges and cat-1 winds for New Orleans, cat-3 near Grand Isle and perhaps inland to Houma, that may or may not prove to be too much for the levees in New Orleans and will more probably cause a lot of damage further west.

Landfall estimate is 30-50 miles west of Grand Isle around 1500 GMT, which is 10 a.m. CDT in local time.

Wind estimates for New Orleans would be in the range of ENE 40-70 mph overnight (it is now 0245 CDT) rising to ESE 50-80 mph by morning with peak gusts of about 90 mph from SSE around 10 a.m. to 1 p.m. This is when the maximum stress will likely occur on the levee system. Grand Isle could see winds of about 100-130 mph during the nearby landfall, in fact the maximum winds may occur close to important oil transfer points along this stretch of the coast, so the major economic impact could come in terms of disruption to the oil pipeline system. About 5-10 per cent of all offshore oil rigs are likely to be disabled for some period of time.