Explanation

[Cookiely]

I would appreciate someone explaining the following link to me. Is the brown area dry air? trough? ridge? I would like links to explain the various aspects of tropical systems. What does a ridge look like? What does a trough look like? Weather 101 for newbies!!
http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html
Thank you for your help.

[Innotech]

dark brown colors are dry air, which is bad for a storm. The area of black with no clouds is the ridge of high pressure air with low moisture content. The areas with bluish and reddish cloudcover is the hurricane obviously, but there is no visible trough feature in that sat image.

[JMGNole]

OK, my turn.

Did the trough that was pulling the storm towards Florida go away last night as predicted? Did I understand that correctly?

Is the expectation that a ridge of high pressure is moving down into the Southeast towards Florida, and that it will push the storm further west?

Thanks.

[Innotech]

yes, that trough is pretty much gone, and in its place a slightly weakened ridge over Florida, which Ivan will follow along its periphery first northwest, and then northeast into the Florida panhandle area.

[Cookiely]

Thank you so much for your help.

[WeatherNLU]

Innotech explained it well. The trough is gone. Ivan will be steering by the ridge and the strength of it and it's ability or inability to re-build west will tell the story.

[Aquawind]

Just to add a bigger picture to it..You can see the Shortwave through up towards West Virginia/Ohio rotating up NE and away from IVAN..notice the dry air is on the backside of the shortwave..Usually on the backside of low pressure you get drier air and that is whats penetrating the gulf..

http://www.rap.ucar.edu/weather/satelli ... g&itype=wv

Ridges are harder to see as they aren't associated with moisture and clouds which is what Sattelite displays..

Everything is pretty much high pressures and low pressure..if it's not low it's high or higher..not always is there a definte center..soo then on the backside of low pressure or in this case the shortwave.. high pressure is trying to develop and the wind from a high is clockwise so they are
reinforcing that push to the south right behind the trough and hold/push everything south untill it has passed the southern edge of the high pressure ridge..

How much all of this effects Ivan is yet to be seen..

[JMGNole]

So, IF the ridge rebuilds to the west, the storm will follow it until it can get around it, kind of like Frances did with the ridge that kept her south?

Any clues on what that ridge will do?

Thanks again, I'm trying to calm my wife's nerves a bit.

I think that Tallahassee is fairly safe, from what I've read on this board. NOT taking that for granted, but it looks to be leaning that way.

[Brent]

So, IF the ridge rebuilds to the west, the storm will follow it until it can get around it, kind of like Frances did with the ridge that kept her south?

Any clues on what that ridge will do?

Thanks again, I'm trying to calm my wife's nerves a bit.

I think that Tallahassee is fairly safe, from what I've read on this board. NOT taking that for granted, but it looks to be leaning that way.

From a direct hit... Tallahassee is defintely safe.

[JMGNole]

Thanks, I needed that.

[therealashe]

Do you think we'll see any TS winds in Tally at all? How about in PCB?

Is everyone completely convinced that Ivan is going to AL/MS?