What does "Tropical Depression " mean, and how does it form?

Did Eaglesfan27 get out in time? When is the main part of the hurricane suppose to hit?

I could easily be wrong, but my guess is that it refers to a depression in barometric pressure.

(and from dictionary.com: )

Main Entry:	tropical depression
Part of Speech:	noun
Definition:	a cyclone in a tropical region that is more intense than a disturbance but less than a storm, with wind speeds of 38 mph or less

SI

I'd worry more about gas prices if the hurricane were heading for Lake Charles.

dola...how about the Louisania homeland security director saying that when the power goes out in the Superdome, it will be 120-130 degrees and RAINING.

:eek:

As sterlingice noted, a TD is a tropical cyclone with maximum sustained winds of less than 39 mph. A tropical cyclone is defined as:

A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

10 PM CDT advisory ... the usually more interesting discussion from the NHC to follow



000
WTNT32 KNHC 290250
TCPAT2
BULLETIN
HURRICANE KATRINA ADVISORY NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
10 PM CDT SUN AUG 28 2005

...POTENTIALLY CATASTROPHIC HURRICANE KATRINA CONTINUES TO APPROACH
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 RUSHED TO
COMPLETION.

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 10 PM CDT...0300Z...THE CENTER OF HURRICANE KATRINA WAS LOCATED
NEAR LATITUDE 27.6 NORTH...LONGITUDE 89.4 WEST OR ABOUT 105 MILES
SOUTH OF THE MOUTH OF THE MISSISSIPPI RIVER AND ABOUT 170 MILES
SOUTH-SOUTHEAST OF NEW ORLEANS LOUISIANA.

KATRINA IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 10 MPH...AND A
TURN TO THE NORTH IS EXPECTED OVER THE NEXT 12 TO 24 HOURS. ON THE
FORECAST TRACK THE CENTER OF THE HURRICANE WILL BE VERY NEAR THE
NORTHERN GULF COAST MONDAY MORNING. HOWEVER...CONDITIONS ARE
ALREADY DETERIORATING 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 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 EITHER CATEGORY FOUR OR FIVE
INTENSITY. WINDS AFFECTING THE UPPER FLOORS OF HIGH-RISE BUILDINGS
WILL BE SIGNIFICANTLY STRONGER THAN THOSE NEAR GROUND LEVEL.

KATRINA REMAINS A VERY 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. A WIND GUST TO 90 MPH WAS
RECENTLY REPORTED FROM SOUTHWEST PASS LOUISIANA.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 904 MB...26.70 INCHES. AN
AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT WILL BE REACHING THE
CENTER OF KATRINA VERY SHORTLY.

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 SOUTHEASTERN
LOUISIANA...SOUTHERN MISSISSIPPI...SOUTHERN ALABAMA...AND OVER THE
FLORIDA PANHANDLE TONIGHT.

REPEATING THE 10 PM CDT POSITION...27.6 N... 89.4 W. MOVEMENT
TOWARD...NORTH-NORTHWEST NEAR 10 MPH. MAXIMUM SUSTAINED
WINDS...160 MPH. MINIMUM CENTRAL PRESSURE... 904 MB.

INTERMEDIATE ADVISORIES WILL BE ISSUED BY THE NATIONAL
HURRICANE CENTER AT MIDNIGHT CDT AND 2 AM CDT FOLLOWED
BY THE NEXT COMPLETE ADVISORY AT 4 AM CDT.

FORECASTER FRANKLIN

Discussion:



000
WTNT42 KNHC 290249
TCDAT2
HURRICANE KATRINA DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SUN AUG 28 2005

THERE ARE CONFLICTING SIGNALS REGARDING THE INTENSITY OF KATRINA.
THE NOAA AIRCRAFT NEAR 00Z REPORTED A PEAK FLIGHT LEVEL WIND OF 155
KT...WHICH WOULD NORMALLY CORRESPOND TO 140 KT AT THE SURFACE. THE
PRESSURE REMAINS EXTREMELY LOW...904 MB AT LAST REPORT. ON THE
OTHER HAND...THE STEPPED-FREQUENCY MICROWAVE RADIOMETER...OR
SFMR...SUGGESTED WINDS WERE IN THE 120-130 KT RANGE...AND LIMITED
DROPSONDE DATA ALSO SUGGESTED SOMETHING A LITTLE BELOW 140 KT.
THERE ARE ENOUGH QUESTIONS ABOUT THE PERFORMANCE OF THE SFMR AT
THESE SPEEDS FOR ME TO STICK WITH THE STANDARD 90 PERCENT
ADJUSTMENT FOR NOW.

THERE HAVE BEEN SOME MODEST CHANGES IN THE STRUCTURE OF KATRINA OVER
THE LAST SEVERAL HOURS. RECENT MICROWAVE PASSES SHOW THAT AN OUTER
EYEWALL IS IN THE FORMATIVE STAGES...AND THE LATEST IR IMAGES SHOW
A LESS WELL-DEFINED EYEWALL WITH MORE EVIDENCE OF OUTER BANDING.
THE NOAA HURRICANE HUNTERS ALSO REPORTED AN EROSION OF THE EYEWALL
IN THE SOUTHWEST QUADRANT. THESE OBSERVATIONS SUGGEST THAT THERE
COULD BE SOME WEAKENING OF KATRINA PRIOR TO LANDFALL. ALL THIS IS
RELATIVE...HOWEVER...AND KATRINA IS STILL EXPECTED TO BE OF AT
LEAST CATEGORY FOUR INTENSITY WHEN IT REACHES THE COAST. AN EYEWALL
REPLACEMENT AT THIS POINT IS NOT ALL GOOD NEWS...AS THEY ARE
GENERALLY ACCOMPANIED BY A BROADENING OF THE WIND FIELD...SO THAT
EVEN AS KATRINA WEAKENS THERE COULD BE AN INCREASE IN THE AREA THAT
EXPERIENCES MAJOR HURRICANE FORCE WINDS.

THERE HAS BEEN NO SIGNIFICANT CHANGE TO THE TRACK FORECAST. THE
INITIAL MOTION IS 335/9. KATRINA IS EXPECTED TO GRADUALLY TURN
NORTHWARD INTO A BREAK IN THE SUBTROPICAL RIDGE ASSOCIATED WITH A
LARGE MID-LATITUDE CYCLONE NEAR THE GREAT LAKES. MODEL GUIDANCE
REMAINS TIGHTLY CLUSTERED...WITH THE NOGAPS SHIFTING JUST A BIT
EAST OF ITS PREVIOUS TRACK. WHILE THERE IS GREAT SIGNIFICANCE FOR
THE CITY OF NEW ORLEANS IN THE DETAILS OF THE TRACK...TRACK
ANOMOLIES OF 30-50 MILES ARE STILL POSSIBLE EVEN 12-18 HOURS OUT.

FORECASTER FRANKLIN


FORECAST POSITIONS AND MAX WINDS

INITIAL 29/0300Z 27.6N 89.4W 140 KT
12HR VT 29/1200Z 29.2N 89.7W 135 KT
24HR VT 30/0000Z 31.8N 89.5W 85 KT...INLAND
36HR VT 30/1200Z 34.8N 88.1W 45 KT...INLAND
48HR VT 31/0000Z 37.7N 85.9W 30 KT...INLAND
72HR VT 01/0000Z 43.5N 78.5W 25 KT...INLAND
96HR VT 02/0000Z 50.0N 70.0W 25 KT...EXTRATROPICAL
120HR VT 03/0000Z...ABSORBED

Crappy's summary from above:

Winds still estimated at 160, but some signs of weakening. However, if eyewall replacement is in fact underway, it could expand the wind field, which means a greater area of destructive winds. More bad news is that the forward movement of the storm has slowed to 10 mph (it was 11 last advisory), which means it could hang around just a little longer.

They're kinda guessing at the intensity because Katrina isn't fitting the model they normally use. I imagine they'll get better info overnight to firm up whether she is indeed weakening in any meaningful way. They have for the moment dropped her to a very powerful Cat 4 at landfall, scheduled for just after 8 AM EDT (7 PM CDT) tomorrow morning.

Unfortunately, the latest track is putting Katrina on a course to do the worst lakeside flooding from Pontchartrain into New Orleans, which is a path just east of the city. Gulf water will be forced into the lake and then as Katrina moves past, the wind will drive lake water into the city. There's a lot more water in the lake than the Mississippi. I don't know how devastating it'll be (I have to hope that the news is exaggerating somewhat to get eyeballs watching), but this will not be a pretty sight come Tuesday when the storm is finally out of the area and they can get up in the air to see what's left.

Why is it weakening? Is there any indication as to that? Does the slowing down of the storm mean that it could gain wind strength? Does all this really matter?

I filled mine up tonight. $3.00/g

Not sure, probably due to the reforming of the eye-wall.


Yes, absolutely. I believe a faster more powerful storm would cause marginally less damage than a slower less powerful storm. Going from 14 mph down 10 mph means at least one more hour of heavy winds and rain and with the expanding area, the damage could be more widely felt.

According to the latest NHC discussion, there are some data sources that are showing slightly lower winds. Also, there are signs of eyewall replacement, where the area of storms immediately outside the eyewall contracts, and basically sucks the moisture out of the inner eyewall. The hurricane is usually weakening during the replacement. HOWEVER, once the outer eyewall completely replaces the inner eyewall and contracts, the storm is often as strong (or even stronger) than it was beforehand. This happened in Andrew, and the storm stengthened right at landfall. If the eyewall in Katrina is replaced, the question is, how long will it take? It could really suck if it completes the cycle right before landfall.

I hope it doesnt turn into The Lost City of New Orleans, but for a few weeks it just might.

Dola: What Im worried about are those with heart conditions and those that are diabetics in the superdome and within the path of destruction. Heart conditions can be exacurbated by the stress caused by the events, heat, etc. and for those that depend on insulin, no power could mean no insulin to ctrl diabetes. AI hope their meds are on ice buckets right now and there's plenty available.

Last night when I topped off Premium was $ 2.88, I just got back from the gym and gas (premium) is noW $ 2. 99....wonder what it will be tomorrow.

Yeah, I got scared to think of what prices will be in the next few days so I went and filled up on $2.42.

Futures still trading at $70 per barrel... I don't think it's too far of a stretch to say that $4.00 a gallon will surface in some parts of the country.

This would be the grimmest of scenarios, but given the amount of time left before landfall, I don't think there's enough time for Katrina to replace the eyewall. At worst, she'll keep present strength or perhaps reach 165, but typically storms do weaken a little before landfall, particularly in the Gulf. I think it's more likely she'll back down to 155 or even 150, though. Then again at this sort of strength, we're talking "many houses and other structures damaged or destroyed", rather than "most houses and other structures damaged or destroyed". It just ain't gonna make much difference.

The 1 AM eastern update has the pressure at 908 mb. Winds are still at 160 MPH. It is still moving at 10 MPH and is 150 SSE of New Orleans.

This form made it where you have to register to view it. I guess they were getting too many hits.

I may sound like a Doomsayer but, After tomorrow this nation will be changed economically, emotionally, and will be physically saken by what will enevitably have taken place in N.O., Mississippi, and Alabama. Landscape and lives will forever be changed. I hope Im wrong when saying this but the shock felt after Sept. 11th will pale in comparison to this if the worst comes to pass. There are countless out there who didnt heed the warning or have no means to flee, I pray for their safety and God Bless and Protect everyone in the path of destruction and God Bless America.

You're right, you do sound like a doomsayer. I don't think it's going to be anything so catastrophic. The shock will be worse than September 11? No way in hell.

Well, it was a downgraded to a four and it is moving a little bit faster at the 3 AM update. This is better news, but it still does not look good.

Now filled into 915 mb and 150 mph, strong Category 4.

Funny thing, the CNN meteorologist blew up at the anchor screaming at her to "let him talk".

The satellite is significantly less impressive, left side of the storm looks to be getting some shear.

I dunno, you don't think people might get more outraged over $4/gallon gas than over two fallen towers?

You're less of a cynic than I am, I guess.

Yeah but that has little to do with the hurricane, it's just the latest excuse for the profiteering oil companies and refinery owners to restrict supply and hike prices. People will have the chance hurricane or no hurricane.

Yeah, but while it's a NIMBY thing (the thought process of "gas prices affect me, while terrorism, well, not so much unless i live in NYC"). It's working counter the "flag-waving, patriotism, us-against-them" mentality. Plus, it's not somewhere on the east coast or California so it's not as sexy of a story. But since there's no attractive white female missing this week, it gives the news stations something to look at.

SI

Weakening and turning away from New Orleans. Good news.

It's better news for New Orleans, that's for sure. But they're by no means out of the woods. The eye is still 4-5 hours from that area, and a ten-mile jog back to the west could greatly increase the damage.

Hurricanes can change direction suddenly, and a westward jog would also be an indication of increased strength.

No one knows yet whether Lake Pontchartrain will break the levees.

From everything I'm hearing, your last statement appears to be the key...

No matter how hard the storm hits, whether it's a direct hit, etc... if the levees break, New Orleans is in a world of hurt...

I thought about your post when I saw this sad blurb:
http://www.cnn.com/2005/WEATHER/08/2...ina/index.html
Three residents of a New Orleans nursing home died Sunday while being evacuated to Baton Rouge, said Don Moreau, chief of operations for the East Baton Rouge Parish Coroner's Office.

The 23 residents were supposed to stay at a church, where one of the bodies was found. The other body was found on a school bus and a third person died at a hospital, Moreau said.

The others were found to be suffering from various forms of dehydration and exhaustion, he said.

Moreau did not know whether authorities would term the deaths storm-related. "These people are very fragile," he said. "When they're loaded up on a school bus and transported out of New Orleans ..."

One person died in similar circumstances during evacuations from Hurricane Ivan, he said.

Joined this thread a little late, but hopefully this thing will pass, we really don't need any thing like this going on right now.

What are the chances that other countries will lend aid to us if this thing really does what its supposted to do?

Reporting on CNN: The roof of the Superdome is failing and may possibly come off.

Could be worse than 9/11 if that happens

Not reallly. They have moved people off the floor incase the roof collapses, but for the most part it just means the Saints will be looking for a new home.

Biloxi is gonna get the brunt bt New Orleans is getting hammered too.

Dola: These reporters are pretty stupid that its pathetic. HEAD INDOORS!!!!!

Stupid FOX had me all worried with their writing at the bottom "Superdome roof has hole, lots of rain getting in."

They finally just had someone on who said the lining came off a little and the structure is just fine. Just means some water is getting in.

Really? The reporter from CNN said he can see daylight through the roof because a section of the roof has come off.

Can we dispense with the 9/11 comparisons?

FOX people are reporting this too now, even though the state official they just had on was downplaying like I said.

Who knows. I am not getting going to take some of hese reports too serious as of right now I think.

Saints are moving to San Antonio....... :p

{shrug} The comparisons seem pretty valid to me, as 9/11 does sort of set the U.S. benchmark for catastrophic loss of life, property, etc. And it's the same standard that the head of disaster planning in New Orleans used for perspective
in the long CNN piece that aired a lot yesterday, so it's not like this is an FOFC thing or something.

9/11 is the catastrophe that all others will be compared to (until something surpasses it).

I agree with sachmo though. Compare this to hurricane Andrew or the tsunami (as an extreme) or another NATURAL disaster, but it not a bunch of assholes who flew planes into buildings on purpose. I think the loss comparisons are valid, but I jsut feel like these events are apples and oranges.

Where is the other thread that ScottVib started?

MSNBC: Reports of Levy breached on North side of N.O.
No Official confirmation though.

This is it. Eaglefan's thread was merged with this one.

By MARY FOSTER

(AP) Some of the thousands of displaced residents take cover from Hurricane Katrina at the Superdome, a...
Full Image



NEW ORLEANS (AP) - Howling wind from Hurricane Katrina peeled holes in the roof of the Superdome on Monday morning as thousands of people huddled inside seeking shelter.

Pieces of metal sheared off, leaving two holes that were visible from the floor. Water dripped in and people were moved away from about five sections of those seats.

The development, around 8 a.m. as the storm neared its peak outside, did not create any visible fear among the estimated 8,000 to 9,000 people who spent the night in the huge arena. Some watched as sheets of metal, flapping visibly, rumbled loudly. From the floor, looking up more than 19 stories, it appeared to be openings of about 6 feet long.

General Manager Glenn Menard said he did not know how serious the problem was. "We have no way of getting anyone up there to look," he said.

Thats what I figured after I spent 20 minutes searching for it. Thanks

This FOX guy is nuts. He is outside in Gulfport. He keeps pausing as he watches stuff fly. He was talking and then just went silent....couple seconds starring off..."Oh wow, that roof just flew off." real quietly....

They just asked him where he goes when not on air, he said the hotel was locked up so they just go duck behind a wall. This guy is gonna have a long day...