Saturday, August 27, 2005

A LOUISIANA LASHING ?

NEXT UPDATE LATE SATURDAY NIGHT,
FOLLOWED BY A LANDFALL IMPACTS DISCUSSION SUNDAY MORNING

FOR THOSE OF YOU WITH LIMITED TIME,
SCROLL TO THE "FINAL WORD" SUMMARY ON THIS STORM


WILL KATRINA BE "THE ONE" FOR NEW ORLEANS? This is a special Saturday morning emergency edition of Foot's Forecast as I will be away from internet access until late tonight. Since many of you reading are either tropical enthusiasts or Gulf coast residents extremely worried about this storm, I have efforted to provide as comprehensive an overview of the situation as I can. If Katrina follows the projected path shown below, it may very well go down as the costliest storm in history, far eclipsing Andrew's $25 billion price tag. The path also takes this storm across the dense oil drilling regions of the Louisiana coast, which means millions will be affected far from the storm due to the expected spike in crude oil and gas prices. Trading on Friday ended before the major westward shift in the forecast track with occured at 5 PM, putting New Orleans in the cross-hairs, where the governor has already issued a state of emergency.

Katrina NHC map

SECTION I: SATURDAY'S FINAL WORD ON KATRINA
This will be updated Sunday morning as we see what the storm is doing then. A "Final Word Summary" is my bottom line analysis of what we face with an approaching storm.

1. WHERE SHE'S NOT GOING. I will say that Katrina is not likely to affect the Mid-Atlantic and Northeast as dramatically as I once anticipated. With landfall and deterioration through the Mississippi Valley, when remnants of the storm arrive in western PA, WV, VA and MD, the biggest impact will be "Ivanesque" rains. However, that also means those rains could spawn damaging floods. If something bad happened to you in Ivan or Jeanne (especially Philly and New Jersey) think now about what you would have done differently then. As for central Maryland, the risk of impact is lessened considerably, which is a relief for students, teachers administrators and parents concerned about disruption to the first week of school.

2. WHERE SHE'S PROBABLY GOING. As everyone who follows big storms already knows, the concern is now shifted to a landfall in and around Southeast Louisiana to the Mississippi Coast as a Category 3, 4 or 5. I do not mean to say this non-chalantly, but for my loyal readers who teasingly accuse me of "Armaggedon Weather forecasting" this is as scary as it gets. Many others, including the unique and always insightful perspective of Fresh Bilge have alluded to the potential catastrophic impacts on metropolitan New Orleans.


3. WHY SHE'S GOING THERE AND NOT ELSEWHERE. The storm is traveling around the periphery of the ever-present Atlantic high pressure ridge. As with any strong tropical cyclone, there also develops an upper level anticyclone above the storm which serves to "ventilate" it and provide an outflow for the moisture rising through the eyewall columns. Depending on the direction of travel, local jet streaks also develop on one side or the other, adding to the ventilation. You can see from satellite imagery that a northeast quadrant jet is helping to ventilate the storm to the south and southwest, which is why you see more convection and cloudiness toward Cuba than toward the north or northwest. An upper level anticyclone over Louisiana is expected to move away as a short-wave trough slides southeast from the Rockies. The combined effect of these two systems is expected to gradually turn Katrina from her currently westerly path to northwest, then north. That is, if all goes as planned. The computer models have had a hard time pinning down this storm's movement until yesterday. The North Atlantic Oscillation provides evidence of this gradual northward turn. Remember that a positive NAO signals landfalls in the Gulf region, whereas a negative or neutral NAO signals Atlantic coastal landfalls. Since Katrina is obviously not going to reach the Atlantic coast as a hurricane again, if you were to superimpose the storm's present position to a longitude parallel with the East Coast, you would see that the theoretical projected path would have easily taken it toward the Carolinas. That's not going to happen, so the only other likely option is a turn north now that the NAO is forecasted to head neutral and even dip negative in the next 72 hours.


4. SO WHAT'S THE FINAL WORD WITH THIS STORM?

It takes more than 72 hours to completely evacuate New Orleans, even with contraflow in full force. There are now less than 72 hours before the storm reaches the Louisiana coast. Wind, swells, waves and surge will begin affecting the coast and flood inland waterways 12 hours or more in advance of the storm's arrival. In actuality, there is less than 60 hours of "quality evacuation time" remaining. If you live in the New Orleans area, you should not be reading this now, you should be packing up and leaving. If I were there, I would. My family's safety is more important than my house, pride or occupation. Many oil rig companies in the storm's path are not waiting for the National Hurricane Center to issue a statement, they are leaving as you read this.

Erratic movements of this storm have proven deadly for some. If the strike cone appears to shift AWAY from New Orleans, it could easily shift back. Anyone living in the I-10 corridor from Lafayette to Pensacola should be READY to leave at a moment's notice.


For a detailed description of the problems facing evacuees to wait until it is too late, review my statements regarding what would have happened IF September 2004's Ivan made the destructive turn we now think Katrina will. Scroll down to find the post dated September 15 with the headline "A Nightmare Journey into the Mouth of Madness." I describe a day by day scenario of how the conditions will change given a mouth of Mississippi landfall by a Category 3 or above.

SECTION II : METEOROLGICAL ANALYSIS & COMMENTARY

Scan down to view previous posts where you can see the dramatic westward shift in the projected path, from mostly inside the Florida panhandle on Thursday, to now 200-300 miles west, encompassing all of Louisiana today. Below is a visible satellite image of the storm from Friday, as it was undergoing a round of intensification...going from 75-80 mph in the early morning hours to 100 mph by 1130 AM.

Katrina satellite 1

This computer model map is what has made everyone so nervous, from forecasters to emergency planners to coastal and inland residents. The "clustering" of the model guidance shows that confidence is increasing on a Mississippi Delta/Southeastern Louisiana landfall. As hundreds of others have already said, it is now not unreasonable to say that given the favorable environment over the next 2-3 days, Katrina could very well be knocking on the door of Category 5 by the time it reaches land. Just considering the "SHIPS" wind speed projections for Sunday night-Monday should give you pause. (SHIPS stands for Statistical Hurricane Intensity Prediction Scheme). Perhaps it is also time for a refresher on the Saffir-Simpson Scale, so that readers in the Gulf Coast threatened by this storm know the differences between Category 3, 4 and 5.

Katrina computer models

Above is a historical comparison of where previous storms with Katrina's current intensity have traveled. As you can see, the paths are clustered around two areas... half the storms headed for Texas, the other half for Louisiana. So it would seem that historical odds are better than average for Katrina to make her mark alongside of Betsy, Camille and Andrew.

Katrina historical map

In just one day, you can see how the computer models have upped the ante for this storm. However, there is a catch! You've read in the news about all the people in south Florida who were unprepared for Katrina's first visit...because they thought the storm would go inland much farther north, as indicated on NHC maps posted earlier this week. So looking back on what happened, 24 hours out, the computers were off by more than 100 miles on the actual landfall location. In a sense, it reminded me of the Charley surprise, when that storm took a sudden right turn shortly after intensifying. So the real lesson here is...do what is right for the safety of your family. If you find yourself ANYWHERE inside the "cone of possible landfall" especially within 24 hours, any emergency management official would tell you it is wise to be ready to evacuate if that is possible, or at the very least, be ready to ride out the storm if you cannot safely leave.

Katrina models 1

Again, note the dramatic differences in the forecast path from less than 24 hours ago. If you live in or around New Orleans, this should give you more than enough reason to start your preparations to leave as soon as possible.

Katrina 8

5 comments:

Mr. Foot said...

Good morning everyone. May not be the best morning for some, though. I see a lot of our Louisiana readers are on or have been on recently. If you are in the strike cone, and are already prepared to leave, and have a few moments, our Northern readers and everyone else would be interested to know your thoughts on this storm. As for the Florida panhandle, you are not out of the woods, but at least not in the corss hairs, for now. If you are new to commenting, it is easy to create an identity to post comments, just create a "fake blog title" give yourself a user identity and you're in.

Terpboy said...

Cat 3

http://www.nhc.noaa.gov/refresh/graphics_at2+shtml/144929.shtml?5day

Julee: it was I who tried to email you last night on da' school system...sorry for any confusion.

Tom said...

Cat 5 at 8 AM Sunday -- oh my...

Mr. Foot said...

hey philaweather...

maybe you can find some research on the internet about a theory behind the influence of sediment currents and static discharge between the storm and the sediment-enhanced water of the Mississippi. I have seen a brief report about this but do not have time right now to look into it. The theory is that warmer waters from the sediment and also the electrical conductivity will increase the storm or keep it at Cat 5 to landfall, as well as increase lightning strike capability. I have no solid source to back this up at the moment but would like to find something on it.

Tom said...

Bastardi was talking about it yesterday, I believe.

That might explain why Camille was a Cat 5 to landfall in MS but then Ivan, about 50 miles E in AL, weakened to a 3.

I'll have to do some research on it today in between watching the feed from NOLA on the evacuations.