11am Ivan-60 mph winds, 999 mb pressure

[Brent]

Tropical Storm Ivan Advisory Number 70

Statement as of 10:00 am CDT on September 23, 2004

...Ivan strengthens a little more as it approaches southwestern
Louisiana and the Upper Texas coasts...

at 10 am CDT...1500z...the Tropical Storm Warning has been
discontinued from east of Morgan City Louisiana eastward to the
mouth of the Mississippi River.

A Tropical Storm Warning remains in effect for a portion of the
Gulf of Mexico coast from Morgan City Louisiana westward to Sargent
Texas.

At 10 am CDT...1500z...the center of Tropical Storm Ivan was located
near latitude 29.2 north...longitude 92.7 west or about 55 miles
southeast of Cameron Louisiana. This is also about 85 miles
southeast of Port Arthur Texas.

Ivan is moving toward the northwest near 15 mph...24 km/hr... and
this general motion is expected to continue today and tonight. On
the forecast track...the center will cross the coast in the warning
area later this afternoon or evening.

Maximum sustained winds are now near 60 mph... 95 km/hr...with
higher gusts. Some fluctuations in intensity are possible until
landfall occurs.

Tropical storm force winds extend outward up to 70 miles
from the center.

The minimum central pressure recently reported by reconnaissance
aircraft was 999 mb...29.50 inches.

Water levels have been running .5 to 2 feet above normal tide levels
along the northwest Gulf of Mexico. Ivan will generate an
additional 1 to 3 feet above these existing water levels.
Therefore...water elevations of 2 to 4 feet above normal are
expected near and to the east of where the center makes landfall.

Rainfall accumulations of 5 to 10 inches...with isolated higher
amounts...are possible near the path of Ivan.

Isolated tornadoes are possible over southern Louisiana today.

Repeating the 10 am CDT position...29.2 N... 92.7 W. Movement
toward...northwest near 15 mph. Maximum sustained
winds... 60 mph. Minimum central pressure... 999 mb.

For storm information specific to your area...please monitor
products issued by your local weather office.

An intermediate advisory will be issued by the National
Hurricane Center at 1 PM CDT followed by the next
complete advisory at 4 PM CDT.

Forecaster Stewart

[Brent]

Tropical Storm Ivan Discussion Number 70

Statement as of 11:00 am EDT on September 23, 2004

a burst of deep convection fired off near the low-level center
earlier this morning and Air Force Reserve recon found 70 kt 1500
ft flight-level winds...or equal to about 56 kt surface winds...
and a pressure of 998 mb. However...since then the convection has
weakened and a subsequent pass through the center indicated a
central pressure of 1000 mb. The initial intensity of 50 kt is a
blend of a 45 kt surface wind supported by the 1000 mb pressure...
and the 56 kt surface wind conversion.

The initial motion estimate is 310/13. Ivan is expected to move
northwestward to west-northwestward and be inland within the next
12 hours over southwestern Louisiana or the Upper-Texas coast.
Afterwards...rapid weakening should allow the low-level circulation
to decouple from the mid- and upper-level circulations. This will
allow the low-level circulation to be steered slowly west and
southwestward by a large ridge forecast to build eastward over the
central and Southern Plains states in 36-48 hours. This track
scenario is consistent with the shallow BAM model...and the most of
the global models.
While Ivan is not expected to be a prolific wind producer...its slow
forward speed for the next several days may bring up large amounts
of Gulf moisture that could result in locally heavy rainfall.

Forecaster Stewart

forecast positions and Max winds

initial 23/1500z 29.2n 92.7w 50 kt
12hr VT 24/0000z 30.0n 94.0w 45 kt...inland
24hr VT 24/1200z 30.5n 95.3w 30 kt...inland
36hr VT 25/0000z 30.6n 96.3w 25 kt...inland
48hr VT 25/1200z 30.4n 97.0w 20 kt...dissipating inland
72hr VT 26/1200z 29.5n 97.8w 20 kt...remnant low inland
96hr VT 27/1200z...dissipated inland

[PurdueWx80]

Hmm...will the surface low stay intact and move back over the Gulf????

[ROCK]

Hmm...will the surface low stay intact and move back over the Gulf????

good question...NHC seems alittle quick with this storm right now?? 15mph is fast and a NW movement??? odd...and that word decoupled?? thats also odd...

[loon]

A) Is the "next 12 hours" landfall being stated considering a 15mph speed?

B) It appears Ivan has all but stopped on the latest Baton R. radar...

cheers,
the loon