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09/06/05 FCST: Hurricane Ophelia

Jason Toft

Looks like the disturbance off the east coast of FL and over the Bahamas has been upgraded to TD 16 as of the 11am EST advisory, which is #1. Looks like it'll move NW and make landfall as Tropical Storm Ophelia sometime this weekend north of Daytona Beach but south of the FL/GA border. I personally think it'll be a good ol' rainmaker, but that might not be a good thing. Watch out for floods! :shock:

If it continues to develop, Ophelia will be our 15th named storm of the season. Wow...just wow.

Thanks all.
 
Not much time, but the GFDL has the storm drifting slowly west on the southern rim of the high and making landfall in Louisiana. Ha ha. That's just one model, and it's had problems this year. Though as I recall it did pretty well with Katrina, and she initialized in the same vicinity.
 
Sixteen has been disorganized all day (even appearing to degenerate to an open wave at some point) though now it appears that the center of TD16 has reformed farther north and underneath intermittant bursts of deep convection. Based on radar data from KMLB, I estimate the center to be located about 90 miles east of Melbourne.

The steering currents influencing the depression are quite weak, so the slow forward movement should continue for another day or so before moving slowly to the W or NW. This should give the system ample time to organize itself over the warm waters of the gulf stream.

There has been a significant decrease in wind shear over the past 24 hours and upper level winds are now very favorable for further development. Waters are warm (~30C), there is good upper level divergence, and the only real inhibiting factor that I can find is the slow forward speed and the associated upwelling, which will become a concern sooner rather than later. That being said, the depression has actually decreased in organization today, so we'll have to wait and see what this system will do.

As far as intensity guidance is concerned, the models are all over the place with SHIPS bringing (Ophelia) to 66kts in about 3 days, whereas the GFDL shows little in the way of intensification. If the depression can get its act together in the short term conditions are favorable for strengthening, but until consistent organization begins, heavy rains are the main threat.
 
Jesus, Mary and Joseph!

http://www.wunderground.com/tropical/track...0516_model.html

Weather Underground has a map showing the model runs, and as you said GFDL is the only one that approaches Louisiana. Unfortunately GFDL fared best in verification analysis and the second-place model, NOGAPS, is not on the Weather Underground chart.

I really hope the GFDL is wrong this time, since it keeps Ophelia over the Gulf for at least 36 hours and aims the storm toward south-central Louisiana, just west of Katrina's worst. While many refugees went to Houston, others went to Baton Rouge and points west in Louisiana.
 
TD 16 has been upgraded to Ophelia. It is still a weak tropical storm with only 40 mph winds, but it's looking a lot better organized than last night. It's developing banding features and the main convection around the center is looking like a comma.

As for the newest computer models from Weather Underground...the GFDL and the UKMET have it going west now and right across central FL. The NHC in their discussion states:
From NHC Discussion #4
ONLY THE
GFDL...SHALLOW AND MEDIUM BAM...AND ECMWF MODELS TAKE OPHELIA
WESTWARD ACROSS THE CENTRAL FLORIDA PENINSULA AND INTO THE EASTERN
GULF. HOWEVER...THEY DO SO ALMOST IMMEDIATELY AND ALSO AS A VERY
WEAK SYSTEM. GIVEN THAT OPHELIA IS ALREADY WELL EAST OF THOSE MODEL
FORECASTS...AND THAT 500 MB HEIGHTS HAVE BEEN RISING MORE QUICKLY
ALONG THE GULF COAST RATHER THAN FARTHER NORTH...SUGGESTS THAT THE
GFDL AND ECMWF MOELS ARE BUILDING TOO MUCH RIDGING TOO THE NORTH OF
OPHELIA. A WEAK SHORTWAVE TROUGH OVER THE CENTRAL U.S.

So, while those two models have it hanging a hard left to cross central FL, the rest of the models have it taking a shallow right and, well, "Pullin' a Jeanne."

I kinda hope this storm doesn't waste too much time out there looping around the Bahamas, which are already pretty battered from Katrina and one other, I think.

Does anyone plan on chasing it if it makes landfall somewhere on the East Coast of FL?

Jason
 
This storm is still very unorganized, and has yet to form an eye, and I doubt it will. But it has gotten quite a bit stronger, from what I can tell. I would not see any reason to chase it...it's so unorganized, and it only has 40 mph winds...I would say when it comes ashore the tornado threat will be minimal, but later on then maybe. Is it developing outer bands now? It acts like it's just standing still, like lingering off the coast of FL, it's been lingering there about....two days it seems.
 
Looks like Ophelia is intensifying this afternoon; it now has an eye which is seemingly becoming better defined with each radar update. Pressure down to 997 mb.
 
Originally posted by Andrew Khan
This storm is still very unorganized, and has yet to form an eye, and I doubt it will.

As of this writing, while satellite representation is not overly impressive, Ophelia certainly has a VERY discernable eye on the 88D from MLB and appears to be moving slowly WNW.

Regards,

Mike
 
Thia may be a bad case of not knowing what the heck I'm talking about, but i almost looks to me like the extreme eastern edge of the circulation center is exposed on the last three frames of the satellite loop. As you said, Mike, it doesn't look all that impressive on the satellite loop, but the radar is awesome. It has some nice banding features. I do think it'll strengthen, ya know, it is sitting right on top of the Gulf Stream!

Jason
 
Originally posted by mikedeason+--><div class='quotetop'>QUOTE(mikedeason)</div>
<!--QuoteBegin-Andrew Khan
This storm is still very unorganized, and has yet to form an eye, and I doubt it will.

As of this writing, while satellite representation is not overly impressive, Ophelia certainly has a VERY discernable eye on the 88D from MLB and appears to be moving slowly WNW.

Regards,

Mike[/b]

Right, and I, so happened, to be talking about SAT. SAT's view is very unimpressive, and while looking at normal RAD, I see a portion of an eye, where as earlier I did not..
 
Well, as of 00:43z I do not see an eye on the IR satellite floater. I do see the 88d from Melbourne, FL showing a distinct center, but I don't believe this an "eye".

I noticed that there has been a huge flare up of convection over the past hour. It doesn't appear to be organizing significantly on doppler and this is likely due to the fact that it is sitting and spinning over the same place. With the upwelling of colder water it's bringing to the surface, I would be very surprised to see significant strengthening in this area.

But we will see what happens. I have seen stranger things happen....
 
I just got back in for tonight and checked the radar loop from Melbourne. It seems to me that Ophelia has taken a pretty distinct turn in the general direction the Cape Canaveral over the length of the radar loop I have here (3 hours). Didn't exactly expect this one, but I'm not all that surprised either, given the aparent 50/50 chance of a turn towards us.
 
Edit: <Link Removed>

So I guess the deal is that with a storm that moves this slow, wobbles can last a very long time compared to the traditional setup. The long wobble toward the Cape ended, and she actually appears to have dropped a few miles south, putting Ophelia in almost the exact same spot she was at this time yesterday. Radar presentation is pretty darn good looking this morning, with a trend toward a tightening circulation over the last few hours. I guess I don't see any reason not to believe she'll sit around there today too. The northward jog in the official forecast hasn't panned out, so while I understand that they like to maintain some continuity with the forecasts, I don't think Ophelia is going to be very cooperative.
 
I will go with a 65/35 approach.
65% says the heat ridge over the mid-east will influence/steer Ophelia westward but very, very slowly. Might be late tomorrow(Fri.) evening before a definitive move is made either way. If the storm manages to cross the south-central Florida peninsula, perhaps the western Florida Panhandle/Alabama Coast area would be a potential target given the massive high that will eventually be "behind the wheel" of the Gulf version of Ophelia.
35% says to side with the models which all steer the storm away from the states and any real threat other than outer band rainfall.
 
More relaible models seem to be coming on board with a track out to sea and a loop south and then west back to Florida's East Coast as a much stronger system. It will be interesting to see if it happens, but that has been the trend.

The NHC advisories are not changed because they have very low conifdence in the track and basically split the track down the middle of what the models forecast. Interesting approach but well understood why. Ophelia will continue to wobble and perhaps reform a center of circulation every so often, as it has done this morning...a little south of its earlier position.

Still not looking for any significant change in strength due to upwelling of colder waters and slight shear.
 
By no means am I an expert on Tropical Systems but as far as I can tell it looks as of 12:30 PM the system is becoming much more organized with a large flare up of convection that now appears to be wrapped around the center, I wouldnt be suprised to see some slight pressure falls through this evening.
 
Cold water upwelling may become an issue, but I believe there is a significant threat of dry air entrainment. A look at the water vapor imagery loop shows very dry air pressing into Ophelia from the north and northwest. So far, O has fought it off, but it wouldn't take much for that dry air to get wrapped into the circulation. Dry air is also trying to press in from the south and southeast. We've all seen how dry air can weaken a storm, and I wouldn't be too surprised should this happen to Ophelia.
 
Latest GFS strengthening this into a major hurricane and taking it up the east coast. The GFS did very well with Katrina but also recently had a strong cane vanish a run later. As slow as it moves it I would agree with Jeff that upwelling would seem a certain problem. I hope we don't have any cities below sea level over there. :shock:
 
Interestingly, several 12z models now do the "hook and loop" technique and bring the big O inland as a major hurricane. There are big differences in track still (as one might imagine)...ranging from Savannah, GA to Hatteras, NC.

EDIT: 5pm: Ophelia Upgraded to Hurricane with 75 mph. They also have the new official NHC track doing the loop-dee-doop through 120 hours.
 
I am not real sure on the exact effect and process of up-welling, I was curious as to the effect the gulf stream has in the upwelling process. Does the gulf stream decrease the effects since it is constantly flowing thus moving the up-welled water out and replace it with warm gulf stream water?
 
I don't mean to get off topic, but I did a search on the gulf stream and came up with this
http://oceancurrents.rsmas.miami.edu/atlan...ulf-stream.html
It says that the gulf stream flow can exceed 5kts at its core, which is about 100-200km wide. It looks like at this time of year, Ophelia would be located near the entrance region to the stronger flow of the gulf stream. I would assume this would mean that the current, in the neighborhood of Ophelia,would average about 3-4kts from the SW. I am sure that the winds from the hurricane have a significant impact on the ocean currents in its immediate vacinity, so it is hard to know how much upwelling would be affected, if at all, by the gulf stream.
 
Upwelling of water over that area will have the same cause and effect as in other places. When upwelling occurs, the warm water on top is displaced and the "colder" water from deeper down is brought up in its place. So, despite their being the presence of the Gulf Stream with warmer water on the surface, there will still be "cooler" water brought up from the bottom of the ocean because the water near the surface is heated more. The water deeper down does not receive as much, if any, sunlight and as a result doesn't warm up as much. The upwelled cooler water is not as conducive for strengthening tropical systems. I hope this helps a little?
 
I think upwelling is less of a factor in the Gulf Stream. First, it's relatively deep and, second, it's flow acts like a conveyor bringing unmixed water into the storm circulation. The current NHC discussion mentions the possibility of upwelling if O. moves off the Gulf Stream.
 
I think it may have been less of a factor due to being on the Gulf Stream but upwelling does occur. Case in point Ophelia is not a Tropical storm at the 4am advisory. I think she will get back to Hurricane strength especailly if she actually starts to move. It will be interesting to see where this thing goes. If the Trough over the plains can move 180-200 miles more East over the weekend it could hopefully push this thing out to sea towards where Maria and Nate ave been hanging out. Im surprised Maria is not Extratropical by now....must be the warm Gulf Stream feeding her. ;-)
 
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