Ivan: Landfall Near Mobile Looks Increasingly Likely

[donsutherland1]

Another day, another shift in my idea to the left.

However, on the bright spot, one saw Hurricane Ivan finally begin its turn more to the north earlier today. Over the last 12 hours, Ivan has been tracking somewhat north of northwest at roughly 328°.

To date, several ideas have fared as follows:

1) Idea of Ivan making a right turn and eventually entering the GOM rather than heading into the Atlantic Ocean: Good

2) An early track along the lines of Gilbert and Allen but turning toward the north: Fair. The turn occurred somewhat later than I had thought

3) Early U.S. landfall idea: From West Coast of Florida to the Panhandle: Fair to Poor. The Peninsula is at low risk of seeing landfall.

4) Last night's idea of landfall around Pensacola +/- 50 miles: Fair

5) Continuity of track ideas once into the Gulf of Mexico: Poor. My ideas have shifted left over the past few days on a regular basis.

However, now that Ivan has made his turn more to the north, I believe it has become more feasible for me to have greater confidence in a track to landfall.

Right now, I'm thinking Ivan will make landfall as a Category 3 (though with a small possibility of retaining Category 4 status) hurricane with the Gulfport to Pensacola area at greatest risk. It is still within the realm of possibility that Ivan aims for New Orleans.

I believe a degree of wind shear will have Ivan in a mode of gradual weakening prior to its making landfall.

If I had to pick a single city over which Ivan's eye would pass, it would be Mobile, AL.

Overall, I believe Ivan will pass within the following distance from these three cities:

Gulfport, MS: About 50-75 miles to the east
Mobile, AL: Near or over the city
Pensacola, FL: 35-60 miles to the west

For Ivan to make landfall at either of those cities, it would have to take the following track from its 11 pm position of 22.0N 85.4W

Gulfport: Approximately 340°
Mobile: Approximately 347°
Pensacola: Approximately 350°

My ideas concerning Ivan's track:

22.5N 85.7W
25.0N 87.1W
27.5N 87.7W
30.0N 88.0W
31.5N 87.9W

[jes]

Sure hope you are wrong.

[rainstorm]

sounds good. not bad compared to alot of forecasts

[ursa minor]

I appreciate the insight, but man I hope you are wrong!

[donsutherland1]

At 11 am, Hurricane Ivan was centered at 23.4N 86.2W. Over the past 12-24 hours, he has been tracking generally between northwest and north-northwest.

Ivan's Track:

12-Hour Period Ended:
9/14 6z: 330°
9/14 9z: 326°
9/14 12z: 330°
9/14 15z: 333°

Ivan has also undergone some weakening today. At last word, Ivan's maximum sustained winds were 140 mph. If one examines the U.S. Naval Research Lab's Hurricane Heat Content Data, one finds that Ivan's weakening as occurred as he approaches an area of negative sea surface height anomalies. In other words, he is encountering more of an impact from a trough that will be departing.

Overall, that experimental model suggests that by tomorrow morning, the environment should be improved with a positive height anomaly of +0.334. This is another suggestion that some ridging will be building over the storm in the wake of the trough.

In addition, the latest CIMSS wind shear analysis shows that wind shear ahead of Ivan has been diminishing over the past 24 hours.

Consequently, while additional weakening is likely today, the weakening trend could come to an end tomorrow for a time. There is even some potential for some restrengthening. However, as Ivan nears the coast, fresh weakening will likely set in.

At this time, my idea of a landfalling Category 3 hurricane continues to look reasonable. The track outlined from last night also looks reasonable:

22.5N 85.7W Actual: 22.5N 85.8W
25.0N 87.1W
27.5N 87.7W
30.0N 88.0W
31.5N 87.9W

Given a combination of the latest computer guidance (hurricane and global models) and the steering wind analyses and tendencies over the past five days at the CIMSS site, no changes are in order at this time.

[donsutherland1]

At 2 pm, Ivan was centered at 23.7N 86.5W. The 3-hour movement was 315° to the northwest. This might be a hint that weak ridging is beginning to build and may be starting to have some impact on Ivan. One will have to wait for later coordinates, to be sure that this is not due to a temporary wobble in the storm's track.

Ivan's Track:

12-Hour Period Ended:
9/14 9z: 326°
9/14 12z: 330°
9/14 15z: 333°
9/14 12z: 331°

At 2pm, Ivan's central pressure had fallen ever so slightly to 931 mb (from 932 mb at 11 am). This is a fresh hint that the storm's weakening may have leveled off. Satellite presentation is also looking somewhat better.

As noted earlier, while additional weakening may still occur today, the weakening trend could come to an end tomorrow for a time. There is even some potential for some restrengthening. However, as Ivan nears the coast, fresh weakening will likely set in.

At this time, my idea of a landfalling Category 3 hurricane continues to look reasonable. The track outlined from last night also continues to look reasonable:

22.5N 85.7W Actual: 22.5N 85.8W
25.0N 87.1W
27.5N 87.7W
30.0N 88.0W
31.5N 87.9W

Therefore, I have left it unchanged.

As for Tropical Storm Jeanne, I am concerned that she will be no Hurricane Gert (1981), even if the opening part of her track is similar to Gert's.

Hurricane Gert's Track:
http://weather.unisys.com/hurricane/atl ... /track.gif

[TLHR]

The people of Mobile, AL are in my thoughts.

Please be safe and get out!!
Surge will be very very bad, if track holds true.

[donsutherland1]

TLHR,

I fully agree with your sentiments. Unfortunately, the latest vortex report suggests that Ivan might well have begun to restrengthen, as I had feared albeit ahead of the timing I had in mind. A later recon. report should prove useful in determining whether or not such a trend has begun. Overall, at a minimum, the weakening has ceased and given its track, this is not a good situation

[donsutherland1]

Throughout the course of the day, Hurricane Ivan has continued his slow turn more to the north. That might stop or even reverse just a bit as ridging develops in the wake of a departing trough. However, it increasingly appears that last night’s idea of a Category 3 hurricane making landfall in the vicinity of Mobile may be realized:

• Through the day, the track outlined last night has been very close to Ivan’s actual trajectory.
• The computer guidance is in strong consensus over the general area for possible landfall, which includes the Mobile area.
• The trough that could have pulled Ivan farther to the east has been lifting away.

As Ivan continues to track north-northwestward, there is a possibility that he could strengthen somewhat at least for a time. However, he may encounter some increased shear just prior to landfall, but this is not a certainty, as the shear has been relaxing over the past 24-36 hours.

Overall, I believe Ivan will make landfall as a Category 3 hurricane. Nevertheless, there is a small possibility that he could retain Category 4 status and possibly rival the strength of Hurricane #5 (1906), which stormed ashore with 140 mph sustained winds and destroyed much of the waterfront from Mobile to Pensacola.

Hurricane Ivan’s Track:

12-Hour Period Ended:
9/14 15z: 333°
9/14 18z: 331°
9/14 21z: 335°
9/15 0z: 339°
9/15 03z: 335°

My ideas concerning Ivan's track:

22.5N 85.7W Actual: 22.5N 85.8W
25.0N 87.1W Actual: 25.0N 87.1W
27.5N 87.7W
30.0N 88.0W
31.5N 87.9W

At this time, no changes in the track from last night are warranted.

For one to have an idea of the magnitude of destruction parts of the Gulf Coast might experience from Ivan’s landfall, the following website has a number of photos from Hurricane Frederic (1979): http://cwrc.geo.usouthal.edu/documents/frederic.html

Finally, there is still a sufficient degree of uncertainty that residents in Louisiana and the Florida Panhandle should keep a close eye on Ivan. One can see reason for this concern in the ensembles. At a minimum, tropical storm-force and even hurricane-force winds could affect these areas. At worse, Ivan could make landfall there.

[baygirl_1]

You're forecast seems to be coming to be. It's very scary for me since I'm no longer there. However, I still have some family and a lot of friends who stayed. And some are in mandatory evac areas... some even on area rivers in the south parts of Mobile and Baldwin counties, believe it or not! I am so scared for them, but they are absolutely refusing to leave. Please, all prayers for them!

[donsutherland1]

Baygirl_1,

All the people in the region likely to be affected are in my thoughts and prayers. I very much hope that Ivan weakens before making landfall. Hopefully all your friends and everyone there will be all right and damage will be as little as possible in such a storm.

[donsutherland1]

Hurricane Ivan Turns to the North...

At 11 am, Hurricane Ivan was centered at 27.3N 88.0W and now heading north. Over the past 6 hours, Ivan has maintained a 353° heading to the north.

Over 12-hour increments, Ivan's turn to the north is also evident:

Hurricane Ivan’s Track:

12-Hour Period Ended:
9/15 03z: 335°
9/15 06z: 335°
9/15 09z: 336°
9/15 12z: 337°
9/15 15z: 343°

Overall, Ivan will likely be passing just to the west of my idea for 22.5N (within 0.3° or so) from Monday night. However, with a turn almost to due north and the proximity of the storm to the track outlined, I see little reason to change the ideas for 30.0N and 31.5N at this time

My ideas concerning Ivan's track:

22.5N 85.7W Actual: 22.5N 85.8W
25.0N 87.1W Actual: 25.0N 87.1W
27.5N 87.7W
30.0N 88.0W
31.5N 87.9W

In sum, I'm still looking for Hurricane Ivan to make landfall as a Category 3 hurricane in the Mobile vicinity. There is a small possibility that Ivan could be of Category 4 strength but the window of opportunity for strengthening will likely close after this evening.

[CaptinCrunch]

http://hadar.cira.colostate.edu/ramsdis/online/RSOgeflt.html

[donsutherland1]

The site seems to be having bandwidth issues and I couldn't access the hyperlink.

[donsutherland1]

At 5 pm, Hurricane Ivan was centered at 28.4N 88.3W and heading almost north. On such a track he will likely make landfall near or perhaps just to the west of Mobile Bay.

Over 12-hour increments, Ivan has tracked as follows:

Hurricane Ivan’s Track:

12-Hour Period Ended:
9/15 09z: 336°
9/15 12z: 337°
9/15 15z: 343°
9/15 18z: 343°
9/15 21z: 346°

Overall, Ivan is now passing just somewhat to the west of my ideas from Monday night. I don't expect much change in his trajectory in relation to that idea. Hence rather than coming ashore near 30.0N 88.0W, Ivan might pass at 30.0N 88.4W.

This would pose the threat of a substantial flood in the Mobile Bay area. As one can see from the following topographic image, the area immediately around and to the north of Mobile Bay is exceptionally flat:



My ideas concerning Ivan's track from Monday night:

22.5N 85.7W Actual: 22.5N 85.8W
25.0N 87.1W Actual: 25.0N 87.1W
27.5N 87.7W Actual: 27.5N 88.1W
30.0N 88.0W
31.5N 87.9W

Adjusted points per latest information:
30.0N 88.4W
31.5N 88.2W

Also, at last word, Ivan's central pressure has fallen to 933 mb. Consequently, I still expect that Hurricane Ivan will make landfall as a Category 3 hurricane, but with a growing possibility that Ivan could at least retain Category 4 strength at landfall.