Hurricane Katrina 7PM Public Advisory (Good news)

[geomon666]

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HURRICANE KATRINA INTERMEDIATE ADVISORY NUMBER 24A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
7 PM CDT SUN AUG 28 2005

...POTENTIALLY CATASTROPHIC HURRICANE KATRINA NOW MOVING
NORTH-NORTHWESTWARD TOWARD THE NORTHERN GULF COAST...

A HURRICANE WARNING IS IN EFFECT FOR THE NORTH CENTRAL GULF COAST
FROM MORGAN CITY LOUISIANA EASTWARD TO THE ALABAMA/FLORIDA
BORDER...INCLUDING THE CITY OF NEW ORLEANS AND LAKE PONTCHARTRAIN.
PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE COMPLETED THIS
EVENING.

A TROPICAL STORM WARNING AND A HURRICANE WATCH ARE IN EFFECT FROM
EAST OF THE ALABAMA/FLORIDA BORDER TO DESTIN FLORIDA...AND FROM
WEST OF MORGAN CITY TO INTRACOASTAL CITY LOUISIANA.

A TROPICAL STORM WARNING IS ALSO IN EFFECT FROM DESTIN FLORIDA
EASTWARD TO INDIAN PASS FLORIDA...AND FROM INTRACOASTAL CITY
LOUISIANA WESTWARD TO CAMERON LOUISIANA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR LOCAL WEATHER OFFICE.

AT 7 PM CDT...0000Z...THE CENTER OF HURRICANE KATRINA WAS LOCATED
NEAR LATITUDE 27.2 NORTH... LONGITUDE 89.1 WEST OR ABOUT 130 MILES
SOUTH OF THE MOUTH OF THE MISSISSIPPI RIVER.

KATRINA IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 11 MPH...AND A
TURN TO THE NORTH IS EXPECTED OVER THE NEXT 24 HOURS. ON THIS TRACK
THE CENTER OF THE HURRICANE WILL BE NEAR THE NORTHERN GULF COAST
EARLY MONDAY. HOWEVER...CONDITIONS ARE ALREADY BEGINNING TO
DETERIORATE ALONG PORTIONS OF THE CENTRAL AND NORTHEASTERN GULF
COAST...AND WILL CONTINUE TO WORSEN THROUGH THE NIGHT.

MAXIMUM SUSTAINED WINDS ARE NEAR 160 MPH...WITH HIGHER GUSTS.
KATRINA IS A POTENTIALLY CATASTROPHIC CATEGORY FIVE HURRICANE ON
THE SAFFIR-SIMPSON SCALE. SOME FLUCTUATIONS IN STRENGTH ARE LIKELY
PRIOR TO LANDFALL...AND KATRINA IS EXPECTED TO MAKE LANDFALL AT
CATEGORY FOUR OR FIVE INTENSITY. WINDS AFFECTING THE UPPER FLOORS
OF HIGH-RISE BUILDINGS WILL BE SIGNIFICANTLY STRONGER THAN THOSE
NEAR GROUND LEVEL.

KATRINA IS A LARGE HURRICANE. HURRICANE FORCE WINDS EXTEND OUTWARD
UP TO 105 MILES FROM THE CENTER...AND TROPICAL STORM FORCE WINDS
EXTEND OUTWARD UP TO 230 MILES. SUSTAINED TROPICAL STORM FORCE
WINDS ARE ALREADY OCCURRING OVER THE SOUTHEAST LOUISIANA COAST.

A NOAA HURRICANE HUNTER PLANE REPORTED A MINIMUM CENTRAL PRESSURE OF
904 MB...26.69 INCHES.

COASTAL STORM SURGE FLOODING OF 18 TO 22 FEET ABOVE NORMAL TIDE
LEVELS...LOCALLY AS HIGH AS 28 FEET...ALONG WITH LARGE AND DANGEROUS
BATTERING WAVES...CAN BE EXPECTED NEAR AND TO THE EAST OF WHERE THE
CENTER MAKES LANDFALL. SOME LEVEES IN THE GREATER NEW ORLEANS AREA
COULD BE OVERTOPPED. SIGNIFICANT STORM SURGE FLOODING WILL OCCUR
ELSEWHERE ALONG THE CENTRAL AND NORTHEASTERN GULF OF MEXICO COAST.

RAINFALL TOTALS OF 5 TO 10 INCHES...WITH ISOLATED MAXIMUM AMOUNTS OF
15 INCHES...ARE POSSIBLE ALONG THE PATH OF KATRINA ACROSS THE GULF
COAST AND THE TENNESSEE VALLEY. RAINFALL TOTALS OF 4 TO 8 INCHES
ARE POSSIBLE ACROSS THE OHIO VALLEY INTO THE EASTERN GREAT LAKES
REGION TUESDAY AND WEDNESDAY.

ISOLATED TORNADOES WILL BE POSSIBLE THIS EVENING OVER SOUTHERN
PORTIONS OF LOUISIANA...MISSISSIPPI...AND ALABAMA...AND OVER THE
FLORIDA PANHANDLE.

REPEATING THE 7 PM CDT POSITION...27.2 N... 89.1 W. MOVEMENT
TOWARD...NORTH-NORTHWEST NEAR 11 MPH. MAXIMUM SUSTAINED WINDS...160
MPH. MINIMUM CENTRAL PRESSURE... 904 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL
HURRICANE CENTER AT 10 PM CDT.

FORECASTER FRANKLIN


The storm is slowing down and getting weaker.

[KyndCulture]

1. winds are down and pressure is up, that's good news. nt

[LuCifer]

6. From the weather channel...

...get THIS:

Hurricane Katrina 4th Strongest Atlantic Hurricane
8/28/2005 7:02 p.m. ET

Hurricane Katrina is now a Category 5 hurricane -- top winds are 165 mph. The pressure has dropped as low as 902 mb. This pressure reading is the 4th lowest on record in the Atlantic Basin.

HOLY SHIT! At least the pressure went DOWN...but to what? The 5th lowest reading on record!?

Lu

[caligirl]

16. dropping pressure is bad news., not good news.

[geomon666]

18. the pressure went up n/t

[msongs]

35. ummm it is still 904 mb which is the same as earlier today nt

[geomon666]

36. it was 903 earlier n/t

[BrklynLiberal]

2. It would be so wonderful if it turned out to be a big fat dud!

[Horse with no Name]

3. Let's hope it can decelerate as quick as it accelerated

Thanks for the good news.:applause:

[Junkdrawer]

4. 904 mb is still a horrible storm...however, if it slows and turns east...

that would be good news. Slows and stays N by NW is horrible news.

[KittyWampus]

9. if it slows, it will push MORE water onto land

[ThomWV]

21. And Will Prolong The Exposure To Tremendous Rainfall

The longer it rains the more it floods - the faster the storm moves the sooner its over at any given point. Its forward speed (often somewhere between 10 and 20 mph) will increase rapidly as it moves north.

For those who don't understand the wind pattern it works like this. The storm has some wind speed as it circulates around the eye - this would be the 170 or 165 or whatever miles per hour they mention. Then there is the forward speed of the storm. The storm will move to the north as any energy machine must (moving energy from hot tropic water to cooler climes to the north) and at the same time will be pushed to the east as it moves northward. The storm spins in a counter clockwise direction if looked on from above. So in the upper right quarter of the storm (if it were a clock face the room between 12 O'clock and 3 O'clock) the wind speed seen on the ground is the indicated wind speed plus the speed of forward motion of the storm. So that 165 mph wind speed could come in at 185 on the ground on one side of the storm. The southwest corner (6 O'clock to 9 O'clock), on the other hand sees the wind speed decreased by the forward speed of the storm.

[cally]

5. whyplease explain why this is good

I assume it's because the winds are less and it's veered off a direct course to NO. Who will get the direct hit now? Have they been evacuated?

[geomon666]

7. The storm has slowed down, which is a double edged sword

The slower it goes the more chance it has of strengthening but, also the direction could change. We want it away from NO. Also the storm has weakened, not by much, but every little bit helps. It's still headed for NO but if it slows down enough that may change.

[arcos]

11. also the slower it goes, the more chance of severe flooding... nt

[cally]

12. thanks

I'm hoping for a miracle.

[DoYouEverWonder]

13. Sometimes these super hurricanes

get so big that they can sustain themselves and start to lose some strength. However by the time you get past 150 MPH winds it doesn't help much.

[petronius]

42. Wasn't it Lili a couple of years ago

that dropped in strength rapidly just before landfall as a result of churning up colder water from deeper below the surface? (Of course, there was another storm a few weeks before the one I'm thinking of that also affected sea surface temperatures.)

[DoYouEverWonder]

45. There is no cold water in the Gulf right now

the temps are the highest I've ever seen them. 88 degrees is about the average at the moment before the storm hit.

[petronius]

46. Right, but the depth of that warm water also matters,

and if colder water is brought up then a storm can weaken significantly. I'm not saying that it's likely in his case, but it is a possible contributor to the big-storm-dropping-quickly idea in the post I was replying to...

I'd be curious to know what the Gulf's temperature profile is along it's the northern edge, and whether that has been factored in to the forecast models. My impression is that only SSTs have been considered in the past, not the depth of the surface layer, hence the surprise at the sudden weakening of Lili(?).

[merbex]

8. Good news? Instead of being hit by a train at top speed

It's only an 18 wheeler barreling at you with no brakes

I heard that analogy on a weather channel

[geomon666]

15. Yeah it's bad but it's not as bad as it was

Not much comfort I know.

[DemNoir]

17. It is every bit as bad as it was

What a misleading post. The "weakening" here is totally insignificant.

[geomon666]

24. Easy

There's a big difference between 160 mph winds and 175 mph winds. I'm hoping, those will continue to drop and the pressure rise. I posted this as good news because it is in a certain sense. It may be a sign the storm is weakening.

I didn't mislead anybody and I don't appreciate that accusation.

[DemNoir]

30. No, there is not a big difference

And look up "eye wall replacement cycle"

[geomon666]

32. Yeah there is

If you stand in front of my car and I hit you going 10 mph, you'll get knocked down. If you stand in front of my car and I hit you going 25 mph hour, you die. See the difference?

And I know what eye wall replacement cycle is, thank you. It has not been confirmed that this is what is happening.

[petronius]

44. You're right, that a weakening is positive

but while 10 mph is hugely different from 25 mph, 160 mph is not all that different from 175 mph in terms of how dead you are. (Sort of like 5000 A-bombs is better than 10,000 A-bombs).

Still, this could be very good news for people on the edges of the strike zone and further inland..

[caligirl]

19. The slight change isn't going to help one bit. Its too powerful

for that change to reduce the risk to NO.

[malaise]

10. She's now moving North North West

Does that mean that the worst part will be north east of New Orleans. That would be a little good news for them but real bad news for their neighbour.

[caligirl]

20. No. The worst part of a hurricane is the north east qudrant winds.

Counter clockwise winds in that quadrant will be devastating.

[Boomer]

23. Moving west is BAD news

The worst effects of a hurricane are in the northeast quadrant. So if the hurricane moves west, that places NO in the northeast side. The counter-clockwise spin pushes surge water right up the rivers.

Moving east is the news you want to hear.... unless you live east of NOLA, of course.

[malaise]

29. I understand the Northeast quadrant part

but she was moving Northwest and is now moving North North west which suggests she is veering more north than west. I thought that was good.

[petronius]

43. Yes, that is good (For NO, anyway)

However, the current projected track is still too close to NO for comfort...

[girl gone mad]

49. Actually, I think moving east would be bad, too..

If aKatrina hits NE of NO, it will dump lots of water from lake Pontchartrain into the city.

[misanthrope]

28. It means they now...

...have to worry about the surge from Lake Pontchartrain.

[petronius]

47. That's a really good point

But still, surge on that side of the track should be lower than on the right side of the track. I wonder what level of wind/surge the causeway is able to handle...

[slutticus]

14. I hope so. But don't let your guards down.

It could just be an eyewall regeneration cycle. It could suddenly strengthen at any time.

Good luck New Orleans. I hope everyone makes it through OK.

I was planning on going to NO in October to party. Now I may be going to help my friends rebuild....either way I'm going. I hope there will be no need to rebuild...

I have so many memories of that wonderful city and the people there

[FreedomAngel82]

22. Yay!

I'm glad to hear that!

[Junkdrawer]

25. It's wobbling N by NW...

It need to turn East REAL SOON if NOLA is to be spared...

http://www.ssd.noaa.gov/PS/TROP/DATA/RT/float-ir4-loop.html

[Individualist]

31. I'm probably seeing what I want to see, but

while watching the radar loop on the Weather Channel a few minutes ago, it seemed at the very end to be making an ever so slight turn to the east. Did anyone else see that, or is it just wishful thinking on my part?

[Junkdrawer]

33. Check the animation at the link I posted... n/t

[malaise]

34. That's what I thought too.n/t

[caligirl]

37. How about galveston, is it in the picture yet?

[steve2470]

40. galveston is way out to the west, no mentions nt

[highplainsdem]

26. The pressure is more important,

according to the meteorologist on FOX right now. He thinks the storm will strengthen, doesn't want people to pay too much attention to some fluctuation in wind speed now.

[DemNoir]

27. Could be getting stronger

It looks like an eye wall replacement cycle may be starting. There is plenty of time for one before landfall.

[caligirl]

38. What is an eye wall replacement, haven't heard that term before.

[Boomer]

39. Here's a NOAA explanation

http://www.aoml.noaa.gov/hrd/tcfaq/D8.html

"Concentric eyewall cycles" (or "eyewall replacement cycle" ) naturally occur in intense tropical cyclones , i.e. major hurricanes (winds > 50 m/s, 100 kt, 115 mph) or Catories 3, 4, and 5 on the Saffir-Simpson scale. As tropical cyclones reach this threshold of intensity, they usually - but not always - have an eyewall and radius of maximum winds that contract to a very small size, around 10 to 25 km <5 to 15 mi>. At this point, some of the outer rainbands may organize into an outer ring of thunderstorms that slowly moves inward and robs the inner eyewall of its needed moisture and momentum. During this phase, the tropical cyclone is weakening (i.e. the maximum winds die off a bit and the central pressure goes up). Eventually the outer eyewall replaces the inner one completely and the storm can be the same intensity as it was previously or, in some cases, even stronger. A concentric eyewall cycle occurred in Hurricane Andrew (1992) before landfall near Miami: a strong intensity was reached, an outer eyewall formed, this contracted in concert with a pronounced weakening of the storm, and as the outer eyewall completely replaced the original one the hurricane reintensified. Another example is Hurricane Allen (1980) which went through repeated eyewall replacement cycles -- going from Categrory 5 to Category 3 status several times. To learn more about concentric eyewall cycles, read Willoughby et al. (1982) and Willoughby (1990a).

[steve2470]

41. Tornado watch until 2 am over that area nt

[brettdale]

48. Yes!!!

Yes!!!