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Ophelia speeds up

By: Dr. Jeff Masters, 8:29 PM GMT on September 12, 2005

Ophelia has decided to start moving, and according to the NHC, is now tracking towards the northwest at about 3 mph. The motion appears much faster--closer to 8 mph, looking at satellite images--but the last two center fixes by the hurricane hunters yeild a speed of about 4 mph, and NHC does some smoothing to take out the well-documented wobbles (trocoidal motion) of these storms, which reduced the forward speed estimate to 3 mph. In any case, the outermost rainband has moved about 9 mph towards the South Carolina coast this afternoon, and will spread heavy rain and 20 - 30 mph winds from Charleston, SC northwards to Wilmington, NC this afternoon and evening. Long range radar out of Wilmington, NC has a good view of these spiral bands. None of the computer forecast models quite anticipated this faster motion, but NHC is sitcking with their landfall near Wilmington, NC, with the storm passing up the length of the North Carolina coast and moving out to sea near Cape Hatteras.

The exact landfall point for Ophelia is much less important than for most hurricanes; the dry air that has plauged the storm the past two days destroyed her eyewall today, and Ophelia doesn't have the narrow concentrated area of winds that usually make the precise landfall point such a big deal. There will be a large area of the coast that will receive tropical storm force winds and a storm surge of 4 -6 feet characteristic of a Category 1 hurricane. Tropical storm force winds extend out about 160 miles from the center, an exceptionally large area for a tropical storm.

Intensity forecast
The latest hurricane hunter mission was at 1:19pm EDT, and showed a strong tropical storm with no eyewall, a central pressure of 989 mb, and peak winds of just 69 knots on the northwest side. Ophelia has moved to an area of ocean she hasn't traversed yet where the sea surface temperatures are a little warmer--about 82 F (a minimum temperature of 80 F is needed to maintain a hurricane). However, there are cooler waters of 79 F near the coast and back where she came from, so there is not much warm water to work with. Ophelia continues to pull dry air off of the coast, and this factor combined with the marginal sea surface temperatures will keep Ophelia from attaining anything more than a weak Category 1 status the next three days. Given that her eyewall has collapsed and will probably take 2 - 3 days to rebuild in a best-cast scenario, I believe that Ophelia will remain a tropical storm the next three days.

Figure 1. Surface winds in Ophelia this morning as seen from the NOAA hurricane hunter aircraft.

Computer model forecasts
Now all of the computer model forecasts take Ophelia northeast past Cape Hatteras and out to sea, but at varying speeds. The NOGAPS model indicates that she might linger near North Carolina until the end of the week before finally getting taken out to sea. The Canadian model no longer thinks Ophelia will move southwest across northern Florida, and has joined the chorus of models calling for a northeast turn past Cape Hatteras and out to sea.

Elsewhere in the tropics
Nothing is going on. Large amounts of dry, dust-laden Saharan air cover most of the tropical Atlantic including the Caribbean Sea, and another large cloud of dust just came off the African coast today. The ITCZ is relatively quiet and too far south to spawn tropical disturbances that might grow into tropical storms. The NOGAPS model indicates a tropical storm might form out of a tropical wave east of the Windward Islands late in the week, but this seems improbable given all the dry air around.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Deb, these rain bands look like the ones from Gaston, where we got 13in of rain in 4 hrs. 10 ft of water downtown Richmond.
Off to work also.
See ya. Maybe I can get a power outage at work.lol.
GAston was a tropical storm, also let's talk about city engineers.

Richmond builds a floodwall, to keep the river out.. 13in of rain in 4 hours floodwall keeps all water in... HMMM Brilliant!!
been perplexed by this one but since wed. he ha said this storm
would hit nc/sc border the models and nhc has been the joke. i
respect some of the 18h aday bloggers on here but they are grossy mistaken about bastardi he like a lot of the great past
forecasters goes by climatogical history and atmosphric trends
rather the gospel of the model lol. he is referring to 2002 scenario unfortunately for gulf we had 3 landfalling systems from this date to early oct hanna isidore(no inner core like opelia) and lili. so i would pay attention if he insists on it happening.
505. WSI
deb1, don't assign ridiculous meanings to my posts. Minimum CAT1 means just that. A minimum CAT1. Winds 75-80mph. That doesn't mean ignore the storm. That doesn't mean it doesn't cause damage. That means a minimum CAT1 hurricane. I don't know why I bother posting in this blog. Some of you just look for fights and hidden meanings where they don't exist. Point to where I said a CAT1 doesn't cause damage, or where I said this storm shouldn't be taken seriously deb.
506. deb1
WSI, get off your high horse and stop taking things so personally.

My point was the language itself, that we refer to hurricanes as 'minumum cat 1', 'minimum cat 2' etc, and it is misleading, because it gets people thinking that if hurricanes can be described as 'minimum', then maybe we don't need to worry about tropical storms. Sure, the wind isn't so bad with a tropical storm, but flooding can be as bad to fix up after the event , if not worse, than wind damage.
507. deb1
hookedontropics, and wasn't Gaston a storm that never quite made it to land, or just crossed over the outer banks?

508. GZ
deb we are getting spotty showers at best. The attitude around Wilmington has undergone a transformation in the past 24 hours. People are taking this storm seriously. A friend of mine just called from Wrightsville Beach who is riding out the storm there, seems to be much more rain and wind out there. She is going to try and check in with me periodically and I will bring any updates so long as we have power....
is it me or is there an eyewall forming?..the last few frames from the wilm radar seem to suggest that.....someone more knowledgeable...which is probably everyone...clue me in..also..when are the next model runs and the next vortex message?
510. WSI
Well that is the way you take it deb1. There is a difference between 74mph winds and 95mph winds. Not one time did I imply any of the meaning you suggested. I simply stated that I thought it would be a minimum CAT1 (ie, barely a hurricane) at most. Now if you want to assign hidden meaning, go ahead. Just put your name at the end of it. I posted earlier in another blog that I have friends down there who boarded up days ago as a precaution. I said that preparing no matter what is always good. I am not taking things personally, but I don't like someone else assigning meaning to my posts when they have no cause.

your eyes are right, this thing formed an inner core very quickly...well guess reformed is a better term
the center of circulation is west of the forecast track....

It'll be interesting to see what it does...the bam models are sticking to their guns on the SC landfall...I think it'll be closer to Pedro at South of the Borderon the NC/SC line...just my guess.....
URNT12 KNHC 131340
A. 13/13:20:10Z
B. 32 deg 11 min N
078 deg 03 min W
C. 700 mb 2993 m
D. 30 kt
E. 48 deg 125 nm
F. 124 deg 066 kt
G. 051 deg 064 nm
H. 989 mb
I. 10 C/ 3047 m
J. 12 C/ 3082 m
K. 10 C/ NA
M. C18
N. 12345/ 7
O. 0.03 / 3 nm
P. AF300 2116A OPHELIA OB 10
MAX FL WIND 66 KT NE QUAD 13:01:50 Z
what i want to know, is that an actual eyewall trying to form?



if it is its headed sw..... but i doubt the storm will follow! LOL
Im a little surprised local businesses in Wilmington arent taking this more seriously. last year during Isabelle, most businesses closed and it only skirted the coast. Ophelia is supposed to be a much more direct blow, yet no closures. I think this could be a mistake making employees come into work, and then have them stuck there when the roads are closed and impassible

YES!!! read my reply to scott and the vortex i just posted
517. deb1
again, WSI, it wasn't your particular choice of words I was commenting on - it's the language itself. 'Minimum cat 1' is an official way of describing storms, which gets people focused on the wind speed and what damage the wind can cause, as opposed to the potential for water and flood damage. There's plenty of potential for this kind of damage, especially in overdeveloped coastal areas, from Ophelia, a TS which may never make it to landfall.

hookedontropics makes a good point about city engineers. If they don't build adequate flood defence systems for their town or city, they have a lot to answer for.
echo..echo...we got the point let's move on...any thoughts on the center of circulation being west of the forecast track?....seems to be moving more nw..hasn't seemed to start any NE turn..
when are the next model runs due....in EST

these are the latest

NEW thread, guys!
Hey leave Perdo outta this. He's only 20 miles south of me.
523. bdnh
According to My Premium Weather Radar The following cities are under the gun: Also the latest Gusts:

As Of 4:00 EDT
Myrtle Beach,SC Heavy Rain Mist N. @ 39 mph
Florence, SC Scattered Clouds N. @ 16 mph
Georgetown,SC Rain ENE @ 26 mph
Goose Creek,SC Overcast 17 MPH
North Charleston,SC
Mount Pleasant,SC

Highway 17,31,526,701,41 Will be effected