Official: TS Ivan at 11 p.m....

[dixiebreeze]

Tropical Storm Ivan Discussion Number 68


Statement as of 11:00 PM EDT on September 22, 2004



although the cyclone is sheared and the cloud pattern is
disorganized on satellite...there is a well defined low-level
circulation. A reconnaissance plane measured 47 knots at flight
level within a convective band to the north of the center. Initial
intensity has been adjusted to 35 knots. These winds are confined
to the northern portion of Ivan. The current southerly shear over
Ivan could relax some...enough to allow the system to strengthen a
little before landfall.

The best estimate of the initial motion is 300/11 knots. This
general motion...around the subtropical high centered over the
eastern United States is expected to continue...and the center
should move inland within the warning area in about 24 hours or so.
This is consistent with guidance. After landfall...the remnant low
is expected to meander until dissipation in 3 or 4 days.

Forecaster Avila

forecast positions and Max winds

initial 23/0300z 27.4n 90.0w 35 kt
12hr VT 23/1200z 28.4n 91.5w 45 kt
24hr VT 24/0000z 29.5n 94.0w 45 kt
36hr VT 24/1200z 31.5n 95.5w 30 kt...inland
48hr VT 25/0000z 32.0n 96.0w 25 kt...remnant low
72hr VT 26/0000z 32.0n 96.0w 20 kt...dissipating

[ROCK]

the intensity is down which is good I guess. A modest TS will be good for my yard.....

[baygirl_1]

Well, I'm glad it looks like he'll just be a rainmaker for y'all in Texas. It sounds like most of y'all want his rain.
Of course, I will be most happy when the "dissipating" part of that forecast finally becomes true!

[Ivanova]

Ivan may have more shockers for us yet



*

[loon]

sure is flaring pretty good right now...

[Cape Verde]

After landfall...the remnant low is expected to meander until dissipation in 3 or 4 days.

<P>Just don't give us an Allison. 4 days of 8 inch rains is not conducive to life as normal.

[Stormcenter]

Ivan may have more shockers for us yet



*

I agree.

[crazycajuncane]

Yeah, if you are talking about that blow up of convection, I do agree.

[donsutherland1]

Just a few quick thoughts on the regenerated Tropical Storm Ivan (the naming debate notwithstanding):

First, Ivan could strengthen from its current level (40 mph maximum sustained winds), with most of the strengthening possibly coming just before landfall.

The latest Naval Research Laboratory's Hurricane Heat Content figures for Ivan's anticipated path are:

September 23 3z: 11.843
September 23 12z: 15.862
September 24 0z: 50.000

Second, given the latest computer guidance, I believe Ivan will probably take the following track toward landfall:

Initial Position: 27.4N 90.0W

28.0N 90.9W
28.5N 91.6W
29.5N 93.6W

[Stratosphere747]

D Sutherland...What do you think of the chances of Ivan stalling in the Houston area and giving us Allison type rainfall?

[donsutherland1]

Stratosphere747,

Right now, I'm leaning against such a scenario, though I expect Ivan to pass just to the north and east of Houston.

[Stratosphere747]

Thanks for the reply Dsutherland....As you can imagine that is the one possible track I would hate to see....

[donsutherland1]

At 5 am, Tropical Storm Ivan was centered at 28.2N 91.6W and continuing to track to the west-northwest. What is interesting is that a growing share of the computer guidance brings Ivan near or inland in northeastern Texas only to bring Ivan southward.

The UKMET seems to try to give Ivan immortality by bringing near to the Texas coast or just onshore then bringing him to a position off the Mexican coast and then due east into the lower Gulf of Mexico.

The models are responding to the possible approach of a cold front and such a wild scenario cannot altogether be ruled out. However, at this point, my thinking remains unchanged from last night with the following outline of a track:

28.0N 90.9W Actual: 28.0N 91.2W
28.5N 91.6W
29.5N 93.6W

[donsutherland1]

8 am update:

Ivan's top sustained winds have increased to 45 mph and Ivan is centered at 28.9N 91.2W.

Last night's ideas concerning a track continue to hold up fairly well:

28.0N 90.9W Actual: 28.0N 91.2W
28.5N 91.6W Actual: 28.5N 91.8W
29.5N 93.6W

[donsutherland1]

11 am update:

Ivan's top sustained winds have increased to 60 mph and Ivan is centered at 29.2N 92.7W.

Ivan's latest position and track put him to the north and east of what was outlined last night:

28.0N 90.9W Actual: 28.0N 91.2W
28.5N 91.6W Actual: 28.5N 91.8W
29.5N 93.6W

At this point, I believe the following adjustments will more accurately reflect Ivan's trajectory:

29.5N 93.1W
30.0N 93.5W

[donsutherland1]

At 8 pm, Ivan was near landfall at 29.7N 93.3W. His top sustained winds were 45 mph.

Last night's estimated Track:

28.0N 90.9W Actual: 28.0N 91.2W
28.5N 91.6W Actual: 28.5N 91.8W
29.5N 93.6W Actual: 29.5N 93.1W

This morning's estimates:

29.5N 93.1W Actual: 29.5N 93.1W
30.0N 93.5W

[donsutherland1]

Some quick track verifications now that Ivan made landfall last night:

Wednesday night's estimated Track:

28.0N 90.9W Actual: 28.0N 91.2W Difference: 18 miles
28.5N 91.6W Actual: 28.5N 91.8W Difference: 12 miles
29.5N 93.6W Actual: 29.5N 93.1W Difference: 30 miles

Thursday morning's estimates:

29.5N 93.1W Actual: 29.5N 93.1W Difference: None
30.0N 93.5W Actual: 29.8N 93.5W Difference: 14 Miles