Katrina's 2nd anniversary, and the tropical update
A tropical wave midway between Africa and the Lesser Antilles (94L) has changed little since yesterday. QuikSCAT data from 4:47am EDT this morning shows a poorly organized system with a weak, elongated circulation. Top winds were 25 knots (29 mph). Visible satellite loops show a limited amount of disorganized thunderstorm activity. Wind shear is a favorable 5-10 knots over 94L, and should not be a problem for it until Friday or Saturday. By then, 94L will be moving through the Lesser Antilles Islands, and may encounter high wind shear if it is far enough north to feel the winds of an upper-level low pressure system that will be just north of Puerto Rico.
The presence of a large, dusty area of dry air surrounding its north side is the main thing holding back 94L. This dry air is being sucked into the circulation and is interfering with the storm's organization. When the dry air encounters a thunderstorm inside 94L, this denser dry air gets incorporated into the thunderstorm's downdraft, accelerating the downdraft, and creating arc-shaped surface cumulus clouds that mark the downdraft's position as it spreads out along the ocean surface (Figure 1). The presence of these arc-shaped surface clouds is usually a good sign that a storm is struggling with dry air and will not intensify significantly for at least the next 12 hours.
Water vapor satellite loops of the region show that 94L has not significantly moistened its environment. As the storm continues further west, it should be able to gradually do so, allowing it more of a chance to get organized. The system should track through the Lesser Antilles Islands on Friday, which is the earliest day I expect it could become a tropical depression. None of the reliable computer models make a believable forecast showing 94L developing into a tropical depression before it reaches the Lesser Antilles. The GFDL develops 94L into a tropical storm once it makes it into the central Caribbean south of the Domincan Republic, and this is a believable forecast, if 94L hangs together and makes it into the central Caribbean. The Hurricane Hunters are on call to investigate 94L on Friday.
Figure 1. Visible satellite image of 94L, show arc-shaped outflow boundaries from thunderstorm downdrafts.
South Carolina low
An area of low pressure has developed a few hundred miles off the South Carolina coast, along an old frontal boundary. This disturbance has been designated "95L" by NHC this morning. QuikSCAT showed a sharp wind shift but no closed circulation around 95L this morning at 6:34am EDT, and measured winds as high as 50 mph. Wind shear is about 15 knots over the disturbance, which is drifting south into a region where wind shear is expected to remain low enough to allow some development this week. I do think 95L will become a tropical depression, and most of the computer models also agree on this. The models disagree substantially on 95L's track, though. Steering currents will be weak in its vicinity, and 95L may spend a number of days wandering erratically. The Hurricane Hunters will investigate 95L Thursday afternoon.
Coast of Africa
The UKMET model is indicating the possible development of a tropical depression by Friday off the coast of Africa. There is a large surge of moisture with at least one strong tropical wave embedded in it coming off the coast of Africa this week, and it would be no surprise to see this wave develop into a tropical depression.
Katrina, two years later
Two years ago today, on August 29, 2005, Hurricane Katrina smashed into the Gulf coast with Category 3 winds and an incredible storm surge up to 27.8 feet high. Wunderblogger Mike Theiss was at ground zero in Gulfport, Mississippi during Katrina, and has posted a blog this morning on his experience, complete with some very compelling photos. His video of the storm surge washing into the hotel he was at is the most amazing storm video I've ever seen.
Margie Kieper's Katrina's Storm Surge feature on our tropical page provides an extraordinarily detailed 16-part examination of each portion of the coast devastated by Katrina. Margie is scheduled to be a guest on the Talking Tropics Internet radio show Thursday night to talk about Katrina's storm surge. Check the listings to see if there are any last minute changes.
The photo above was taken from Part 8: Lakeshore to Waveland, MS of Katrina's storm surge. An excerpt from the text:
I found an astonishing photo, of the peak of the surge in Waveland, which didn't appear to be faked, but I'm pretty much of a skeptic. The photo had this caption, "Photo taken in Waveland, MS, just North of the Railroad Tracks during Katrina around 9 AM by Judith Bradford." Note that it is being taken from the second floor window of a home, and that the water is close to the roof line of the first floor. There is a man perched on what is left of a home across the street, wearing a tiny life jacket and clutching a neon green pool noodle. There are electric lines running down from a pole to a home from left to right. In the distance on the right is a home with water up to the roof line. It is likely after 9am, as the bulk of the surge came between 9 and 10 am (that is when most of the fatalities occurred along the Mississippi coast), and probably the eye is already overhead, as the water is relatively calm and there appears to be little wind or rain, even though the pine trees are bent from the recent force of the eyewall winds.
The information provided by the Bradfords regarding the surge was very specific. The power went out at around 6:30am at their Waveland home on the morning of the 29th. They were staying in the home for a couple of reasons; first, because the home had not received any water at all from Camille, and, secondly, because both work in the medical field and needed to be available after the storm. At almost exactly 8:30am, water started coming over the railroad track embankment, from the coast, and into their yard.
Their home is 18 inches off the ground, and the first floor has 8-foot ceilings. There is an 18-inch truss between the 1st and 2nd floors, and this is what saved their 2nd floor from being flooded. In a matter of only five to ten minutes the water came up six feet, and quickly filled the first floor after that. Judith said that is why they saved so little from the first floor; they had no time to get anything. She first tried to shut the living room front door, but the force of the water burst the door open. She grabbed a camera and the Bradfords and their children ran upstairs. They marked the high water mark (HWM) on the inner stairwell showing how high the water came ? a little more than six more inches into the truss, which is a total of 10 feet of surge.
They saved two other people besides the man who was floating by on the roof in the photo. He was a chef named Glen, holding a four month old dachshund named Pinky, in the surge. He had lost his other dog and three cockatiels when his mother's home collapsed. The roof wedged against their van, underwater, and stopped, so they were able to save him. Bill Bradford told me when he swam out to rescue that man, that the water was so warm it seemed almost hot. He said the current was nothing like white water, but was a gentle continuous flow.
Because their home is right by the railroad tracks, it is not as high in elevation as I had thought. It is around 17 feet elevation. That is close to the HWM observed in Pass Christian, 27 feet.
With such a good quality HWM, I wondered why their house was not surveyed. Judith Bradford told me that no one from the federal government seemed to realize their house was there. The road leading up to Jeff Davis (they own 6 ½ acres and raise miniature horses, which were drowned in their stables when the surge came) was filled with debris. The teams doing Search and Recovery for bodies didn't even check the house because they didn't know it was there; it was a good thing the family survived!
The water started to go down sometime after 11am, and by noon was about chest high, and by 2pm about waist-deep. The water finally left the house completely by about 4 or 5 pm that evening. She believes the railroad track embankment kept the water from receding faster. "
I'll have an update Thursday morning, unless there's a major change in 94L or 95L. My thoughts and prayers are with all those affected by Hurricane Katrina today. Let us not forget what happened two years ago.
Jeff Masters
Reader Comments
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I am not an expert and don't analyze what you say to see if it is accurate, or whether what you say comes to pass. I know sometimes it doesn't (as with all forecasters).
However, what I appreciate most is that they are very well written and concise, with reasoning set out. A lay person can follow and understand what you say.
At a non-technical level, your forecasts are the thing I look forward to reading most every morning (after my email!)
Wind shear and dry air don't seem to be a problem with the CV wave.
Yep, seems good for development. nhc didnt talk about it in their 11am TWO, perhaps they will at 5pm. maybe they just forgot lol. They miss things sometimes
I wouldn't feel safe if they missed things.
a 1010 mb low along the wave near 11n. Broad low level
inverted-v curvature with an embedded low level center is noted.
This system is expected to be moving into a more favorable
environment for further development over the next few days.
Isolated moderate convection is from 8n-13n between 42w-49w.
...from the 205 on 94L
They don't miss things lol. 90L was an invest near the CV islands.
I wouldn't feel safe if they missed things.
They miss things sometimes. perhaps they just wanted to watch it for a bit. they could be starting to run out of room in their TWO, lol
What about the fact that the boundaries perpetuate instability once they are in a moister environment and are then serving to transform a tropical depression to a tropical storm?
TROPICAL WAVE IS ALONG 26W/27W S OF 20N MOVING W NEAR 10-15 KT
WITH A 1011 MB LOW ALONG THE WAVE NEAR 14N. BROAD INVERTED-V
CURVATURE WITH A SMALL LOW LEVEL CIRCULATION IS NOTED.
SCATTERED MODERATE CONVECTION IS MOSTLY W OF THE WAVE AXIS FROM
11N-15N BETWEEN 27W-30W.
The nhc's TWD said it has a LLC, you would think that in itself would make it a invest lol
TCW- The models seem to be bouncing back and forth on losing 94L or developing it into a weak TS.
As long as it remains weak, the models will be all over the place.
That is Hurricane 101 you speak of there. Past couple runs have been trending more to the WNW to NW and the low level flow ahead of 94L on the satellite is also heading WNW to NW. Just using the look out the window method to say the models may be getting a better handle on keeping 94L weak and will move more wnw is all.
If you go to my blog , there is some excellent information about how you could significantly lower your homeowners insurance.
I have even posted my email if you have any questions.
is "96L" the wave northeast of 94L
no the "soon to be 96L" is the LLC located southwest of the CV islands
Link
10EGIL.35kts-999mb-196N-1100W
y do you keep posting this over and over we can see
Approximate location of center:
30W, 7N (it's a very broad system though)
Upper Level Divergence: Between 5 and 20 units (I have no idea what the actual label is so I'll just call it units). Present around the entire system.
Lower Level Convergence: between 5 and 10 units. Interestingly, there is no lower level convergence where the low appears to be.
Wind Shear: between 10 and 20 knots. Shear is higher east of 25W. It's hard to tell what the shear will do; certan areas out in front of the system are decreasing while other such as the area around 94L are increasing.
850mb Vorticity: broader and much stronger than 94L's. Shows the center at 25W and just north of 10N.
Dry Air: preceding waves such as 94L have cleared a path of damp air all the way to 50W. Shouldn't be much of a problem unless the system takes a sudden jog to the north.
SAL: isolated patches of dust are just northwest of the center of circulation. Some dust may be cutting off the COC from the huge mass of convection underneath it. Out in front of the system, there is a neglegible amount of SAL.
Latest QuickSCAT: the latest scan caught the eastern edge of the cirulation. It seems to be hinting at a surface low.
MODELS:
-CMC: shows a gradual development but then weakens it as it nears 45W.
-GFS: fluctuates the system in strength and does nothing sudden with it. GFS thinks it will be slow to develop which currently seems likely.
-MM5FSU45(a): shows the same thing as the GFS (which is not surprising considering that the MM5FSU45a is initiated by the GFS).
-NOGAPS: does not develop it. Keep in mind that the NOGAPS did not develop Dean either.
-UKMET: develops it into a pretty large (but still weak) system in only 48 hours.
-ECMWF: shows the low on their maps but seems to not develop it. Weird; they had it as a strong TS on their last run. I'd rather see the next run before calling the ECMWF a downplayer of this system.
Satellite Presentation: Very well organized. A huge elongated bulge of convection is south of the actual COC. The area around the COC is beginning to regain convection. African dust may be seperating the northern mass from the southern.
My Predictions: I agree with JP and hurricane23. I think 96L will be designated by the Navy tonight or tommorow. This has a shot at a named system.
the wave that is crossing over to the BOC looks to be hanging in pretty good. It also looks to be going a move northward movement than west. what do ya think
The tropical wave over the Yucatan appears to be migrating towards the NW, and will re-emerge tonight over the SW GOM. There is a new burst of convection in the south central GOM associated with this wave that will just not go away.
Posted By: hurricane23 at 2:02 PM GMT on August 29, 2007.
This is the wave to place close attention in the coming week or so as it already at a dangerous latitude and looks fairly well organized on morning visibles.
ok hurricane23, in that pic you posted, there two blobs, which one is the potential?
the elongated one or the little round one. Because on the EUMETAT the little round one seems to have rotation.
this is the posting I asked earlier on the previous blog, the little round one-now refered to as the future 96L
and thank you all for responding to me, I really appreciate it.
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