Mobile Bay Nightmare Scenario May Be Averted

[donsutherland1]

Over the past 9 hours, Ivan has been tracking at 10°, which is mainly north but a little movement to the east. This slight jog to the east may well prove to be crucial as Ivan ultimately makes landfall.

Consequently, if that track is maintained to landfall, Ivan could be reaching 30.0N 87.9W. This would be far better than if Ivan had crossed 30.0N 88.0W/88.1W.

Based on the trough beginning to nudge in from the west and Ivan's current path, I believe Ivan will cross the following points:

30.0N 87.9W
31.5N 87.6W

At the same time, Ivan is now moving over cooler coastal waters and his central pressure has risen slightly to 933 mb. His top winds remained at 135 mph.

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

Hurricane Ivan’s Track:

12-Hour Period Ended:
9/15 18z: 343° North-Northwest
9/15 21z: 346° North-Northwest
9/15 23z: 353° (11 hours) North
9/16 01z: 354° (11 hours) North
9/16 03z: 358° (11 hours) North

Last 9 Hours:
9/16 03z: 10° North

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 87.9W
31.5N 87.6W

The recent tendency of Ivan to begin to fade ever so slightly to the east warranted an additional post given its implications--happily better ones--for Mobile Bay if the track is continued.

With regard to my track and today's several small changes:

I left the track unchanged for the past two days. However, there were small changes along the lines of the tenths of a degree that were present but I did not consider them sufficiently significant to adjust the overall track mainly because Ivan was out in the Gulf of Mexico and landfall was not imminent.

With landfall approaching, I posted the small changes in my ideas, as they could have had large implications. For example, if Ivan passes through 30.0N 88.0W/88.1W, Mobile Bay would suffer tremendous flooding. If Ivan passes through 30.0N 87.8W/87.9W, the worst of the flooding could be avoided, though there would still be some flooding.

As a result of posting the changes today, you saw me cite 30.0N 88.4W this morning, 30.0N 88.1W earlier this evening, and now 30.0N 87.9W after the 11 pm report given its significance. Had Ivan been well offshore, I would not have made these changes and left the initial idea as it was.

Overall, the 48-hour idea will have proved fairly reasonable with respect to the track Ivan ultimately took.

[AL Chili Pepper]

Pensacola....I hate it for you bro's, but ya'll are going to get the worst of this storm. Stay safe.

[yoda]

Good discussion Don, and I believe the W FLA will see the NE quad.

[donsutherland1]

Yoda,

This will be a terrible storm for the extreme western Panhandle, not to mention coastal Alabama and Mississippi. Parts of Louisiana will be hard hit, as well.

[dennis1x1]

louisiana? im still looking for any reasonable argument that louisiana isnt seeing the worst it will....the eye is due east of the southeast coast.....and they are seeing 30mph sustained winds.......why is it going to get any worse?

[miamijaaz]

don:

I just saw Max Mayfield on CNN. He essentially confirmed your post, although he did say that it is still too close to call as to whether the eye will pass east, over or west of Mobile Bay.

[MGC]

Yes it looks as if Mobile might exscape the eastern eyewall. But, they will still likely get the western eyewall. Although not as strong it will still be a significant blow. The greatest damage will be from Ft Morgan eastward to Destin due to a potential 20 foot storm surge and winds in excess of Cat 4 intensity. I expect extensive damage from Ivan......MGC

[donsutherland1]

Miamijaaz,

It's an extremely close call. 0.1° longitude will likely make a world of difference. Hopefully, the trend will be sustained and Ivan will pass to the east of Mobile Bay.

[donsutherland1]

Dennis1x1,

The trough coming in from the west has made somewhat more progress than anticipated on the computer guidance. Thus, the situation in Louisiana will be better than it would otherwise have been.

[dennis1x1]

thanks...that makes some sense....its really surprising and will be the talk of new orleans unfortunately (hopefully doesnt cost the next time)

im still baffled at the 10pm local weather reports in mobile and pensacola........the gradient of wind increase must be phenomenal

[donsutherland1]

1 am EDT position: 29.7N 87.9W

This latest position indicates that Ivan continues to move slightly to the east as it comes north. Ivan is now in a position to avoid a catastrophic Mobile Bay flood. There will be some flooding, but it could have been far worse.

Unfortunately, areas to Ivan's east will not fare as well.

With Ivan just 40 miles south of the Alabama border, he remains a Category 4 storm with 135 mph winds. Landfall should occur before sunrise.

[Psychonaut777]

The CNN met. expects landfall in the bay..

[MWatkins]

Don...

Once again excellent analysis...an honor to have you working as a storm2k forecaster...outstanding analysis backed up with facts and synoptic reasoning. And just about 100% accurate to boot.

MW

[GuffMorlix]

The CNN met (Arlene somebody) says the eastward movement is a wobble caused by showers in the eyewall, and that Ivan will resume a more northward course and go ashore just west of Gulf Shores, on the eastern side of Mobile Bay.

[donsutherland1]

Mike,

Thanks for the very kind words. Great job with Ivan, as well!

Best wishes.

[dennis1x1]

looks like orange beach is the target of the eastern eyewall.....at least its between the Bays...

[donsutherland1]

GuffMorlix,

Bad as Ivan's track might be for Gulf Shores--and I expect a lot of damage there--had it been centered as little as 0.1°-0.2° farther west, the situation would have been far worse for the entire Mobile Bay area. A truly catastrophic flood could then have occurred.

[GuffMorlix]

Don, you said the latitude for this critical 0.1 degree to .02 degree movement east was 30.0. Ivan is about .03 degrees below that mark right now, so we won't know for certain if we've avoided the catastrophic flood around Mobile Bay until the next advisory, correct?

[dennis1x1]

you can see from this radar shot that the eastern eyewall will not move up the Bay with its intense northerly winds.......thereby eliminating the threat of a possible catastrophic surge event at the north end of the Bay..

http://wxweb.meteostar.com/radar/site/MOB.shtml?MOB

[Anonymous]

Dont downplay the surge to the point of nothing. While not catastrophic, the surge will still greatly affect the bay. Not to mention Gulf Shores, and Pensecola will get a good hit from the surge as well.