11pm Ivan-135 mph winds, Cat 5 possible

[Brent]

Hurricane Ivan Advisory Number 15

Statement as of 11:00 PM AST on September 05, 2004

...Category 4 Hurricane Ivan continues to strengthen...

at 11 PM AST...0300z...the government of St. Lucia has issued a
Hurricane Watch.

A Hurricane Watch remains in effect for Barbados.

A tropical storm watch remains in effect for Grenada and its
dependencies.

Interests elsewhere in the Lesser Antilles should monitor the
progress of Ivan.

At 11 PM AST...0300z...the center of Hurricane Ivan was located near
latitude 10.8 north... longitude 49.4 west or about 700
miles...1130 km... east-southeast of Barbados.

Ivan is moving toward the west-northwest near 21 mph...33 km/hr...
and this motion is expected to continue for the next 24 hours.

Maximum sustained winds are near 135 mph...215 km/hr...with higher
gusts. Ivan continues to strengthen rapidly and is currently a
category 4 hurricane... if this intensification phase continues...
Ivan will approach category 5 status during the next 12 to 24
hours.

Hurricane force winds extend outward up to 35 miles... 55 km...
from the center...and tropical storm force winds extend outward up
to 140 miles...220 km.

Estimated minimum central pressure is 948 mb...27.99 inches.

Repeating the 11 PM AST position...10.8 N... 49.4 W. Movement
toward...west-northwest near 21 mph. Maximum sustained
winds...135 mph. Minimum central pressure... 948 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 2 am AST followed by the next complete advisory at 5 am
AST.

Forecaster Jarvinen/hennon

[Brent]

Hurricane Ivan Discussion Number 15

Statement as of 11:00 PM EDT on September 05, 2004

satellite intensity estimates from all agencies suggest that Ivan
continues to rapidly intensify and is now a category 4 hurricane
with maximum winds estimated to be near 115 kt. Convection is
remarkably strong in the core region with peak cloud tops
approaching -80 deg c. The upper-level outflow remains strong in
all quadrants.

The initial motion is WNW...285/18. All forecast models suggest a
similar track for Ivan over the next 96 hours. A strong deep-layer
anticyclone is forecast to remain to the north of the hurricane,
bringing Ivan into the vicinity of Barbados in 36 hours. For the
120 hour forecast period a strong consensus remains in the
dynamical models...only the GFS significantly weakens the ridge and
moves Ivan farther to the north and east. After 72 hours the
forecast track is adjusted to the north and east of the previous
forecast...near the model consensus.

Ivan is forecast to continue deepening over the next 12-24 hours.
Both SHIPS and GFDL guidance bring Ivan up to 125 kt at the 24 hour
forecast period. The ships rapid intensity index suggests that the
current intensification phase will continue as the probability for
rapid intensification is nearly Nine Times the Sample mean. Given
the current intensification trend and the extremely favorable
conditions along the forecast track...Ivan is forecast to reach 130
kt in 12 hours. Fluctuations in intensity are likely after that
time.

Forecaster Jarvinen/hennon

forecast positions and Max winds

initial 06/0300z 10.8n 49.4w 115 kt
12hr VT 06/1200z 11.4n 52.1w 130 kt(150 mph!!!)
24hr VT 07/0000z 12.2n 55.6w 130 kt
36hr VT 07/1200z 13.0n 58.9w 130 kt
48hr VT 08/0000z 13.8n 61.7w 130 kt
72hr VT 09/0000z 16.1n 67.1w 130 kt
96hr VT 10/0000z 19.7n 71.7w 60 kt...inland
120hr VT 11/0000z 23.0n 75.0w 75 kt...over water

[senorpepr]

Wow. Amazing.

[kevin]

Do they ever forecast that strong for that long?! oh man.......

[senorpepr]

...although it's a small hurricane: 35mi 64kt wind radius.

[canegrl04]

By the time we wake in the morning,Ivan will be the big 5

[Bane]

Amazing that these storms continue to get so strong this year.

[Brent]

The NHC really weakens it over Hispanola. Does anyone really think it'll go from 150 mph to 70 mph after only being over the island for 12-18 hours?

[OtherHD]

The NHC really weakens it over Hispanola. Does anyone really think it'll go from 150 mph to 70 mph after only being over the island for 12-18 hours?

Yes.

[kevin]

Hispaniola cannot be conquered tropically. If it goes there, it could lose everything.

[senorpepr]

The NHC really weakens it over Hispanola. Does anyone really think it'll go from 150 mph to 70 mph after only being over the island for 12-18 hours?

With mountains as high as 10,000ft, the NHC's forecast is not far-fetched at all.

[paulvogel]

we would have 3 cat5S hit florida every decade!!!!

Florida would be one big park, with Hurricanes as the attraction.

No cities would be there.



LOL

[clueless newbie]

Looking at 0215 IR on http://www.cira.colostate.edu/ramm/rmsd ... PICAL.html
there is almost perfect doughnut of extremely deep (bright red) convection. Looking at the loop shows significantly improved structure in the last 6 hours. I would not be surprised to wake up to Cat5 tomorrow morning.

Btw., strange waves appeared for a while in the outflow in the SE quadrant: first running N to S in the very SE corner, then running E to W a bit to the W of that.

[SootyTern]

The NHC really weakens it over Hispanola. Does anyone really think it'll go from 150 mph to 70 mph after only being over the island for 12-18 hours?

Yes.

Why? Somewhere I think I've heard that larger 'canes do worse in terms of maintaining intensity when crossing mountainous terrain and less well-developed ones can skirt across with relatively less decrease, but I don't know what the mechanisms are that cause this difference in effect. Also, does size of the storm (miles across) affect how much it will lose strength over the mountains?

Pardon this post in 'oooh...meterology !' mode; the thought of a 150 MPH cane hitting Hispaniola is upsetting to say the least in human terms. Pray for shear...

[Bane]

If it is still moving at a good clip, it won't lose that much steam.

[lahurricanewatcher]

By the time we wake in the morning,Ivan will be the big 5

Who can sleep? I'll probably keep slipping out of bed to come check the board.

[Brent]

If it is still moving at a good clip, it won't lose that much steam.

Exactly, They don't "stall" it. It moves across it in less than 24 hours.

Yes, significant weakening will occur, but HALF of it?

[Innotech]

if Im in a light sleep mode around 1 am central time, Ill come back and check myself too. I might just wait for 4 am though, sinceI get up at that time normally. (yeah I actually do, every single day and Ive gotten used to it)

[calidoug]

CAT5 to TS over Hispanola? I don't think so. Cat 2, maybe.

[Innotech]

If it is still moving at a good clip, it won't lose that much steam.

Exactly, They don't "stall" it. It moves across it in less than 24 hours.

Yes, significant weakening will occur, but HALF of it?

that all depends on its movement when its over hisdpaniola. Perhaps if it slows down or encounters hte very biggest mountains it will weaken significantly. a faster storm will still lose strength, but not early asm uch because it isnt spending much itme over the isle. This is why charley left the same Category 4 damage over much of Florida but Frances weakened so rapidly. forward speeds varied a lot.