Ophelia re-strengthening

By: Dr. Jeff Masters , 2:14 PM GMT on September 09, 2005

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Ophelia weakened last night, as strong upper-level winds out of the south continued to shear the storm's southeast side. The NOAA high-altitude jet measured a thin layer of southerly winds of 20 - 30 knots at the top of the storm, which is a significant amount of shear. Ophelia had been able to slowly strengthen the past two days in the presence of 10 - 15 knots of shearing winds, but 20 - 30 knots of shear almost always causes weakening, as we observed.

Indications are now that the shear has relaxed significantly, and Ophelia is intensifying once more. The 8am EDT hurricane hunter flight found a center pressure of 983 mb, Ophelia's lowest pressure yet. This is a drop of eight mb in just four hours, the fastest rate of intensification we've seen with this storm so far. The 10am hurricane hunter report shows the pressure has stopped dropping, though, with a 984 mb reading. Satellite imagery shows a well-organized and expanding area of outflow, but restricted on the southeast side where the shear is. The storm is growing in size, and is transitioning from a small storm to a medium-sized one.

Ophelias's surface winds are below hurricane force, but with the large fall in pressure seen by the hurricane hunters, it is only a matter of 12 hours or so until the winds increase to hurricane force once more. The maximum observed winds at 8am were only 57 knots (65 mph) at 5,000 feet altitude, but had increased to 67 knots (77 mph) on the 10am hurricane hunter eye report. The maximum temperature in the eye was 2C warmer than just outside the eye, which is not very impressive. This difference was 5C yesterday. Doppler radar wind estimates also indicate maximum winds are below hurricane force.


Figure 1. Wind speed estimates from the Melbourne Doppler radar. The red colors on the south side of the eyewall indicate strong winds blowing away from the radar. Because the radar uses the Doppler effect to measure wind speed, it cannot tell what the wind speed is when the winds don't have a component of motion towards or away from the radar. Thus, winds on the east and west eyewall are coded white (a speed of zero towards the radar) and the winds on the north eyewall are coded blue (blowing towards the radar).

Ophelia's signature on long range radar out of Melbourne is not too impressive; only half an eyewall is apparent. Very little convection exists on the east side of the storm. The radar also indicates a slow north-norhteast motion away from Florida. Looking at this radar signature, it is surprising to me that the hurricane hunters measured such a large drop in pressure.

OK, now the "where will Ophelia go?" game. We are still at least four days from a possible landfall, and steering currents are weak, so the track forecast is highly uncertain. Data from the NOAA jet's high-altitude mission last night were used to help initialize the computer models today, and they are much more tightly clustered. This gives credence to the idea of a landfall in Georgia or South Carolina sometime in the Tuesday - Thursday timeframe. The NHC did not buy this initially, prefering to see another run of the models before committing to this idea. Now, however, they have come on-board and are also forecasting a landfall in South Carolina four days from now. Certainly, residents of Florida and North Carolina cannot breathe easy yet, until the models portray a more consistent picture of Ophelia's future track.

The intensity forecast, as usual, is highly speculative and low-confidence. The models all show Ophelia strengthening to a Category 1 to Category 3 hurricane by five days from now. The shear that has dogged Ophelia its entire life is forecast to remain, at least in the short term. A weak trough pushing off of the East Coast Saturday may also generate some shear the next few days, as could a large upper-level low over Puerto Rico approaching from the east. Dry air on the north side of the storm may also be a problem for Ophelia. Clearly, there are many hurdles for Ophelia to overcome. That being said, this storm has shown the ability to intensify in the presence of some modest shear, and as she expands in size, will be able to shrug off the shearing winds surrounding her more easily. Ophelia is over warm Gulf Stream waters and will remain so for the next five days. All these factors considered, and given the fact that hurricanes during this unprecedented hurricane season of 2005 have shown an uncanny ability to become intense hurricanes, it would be no surprise if Ophelia grows to a Category 2 or 3 hurricane by early next week.

Elsewhere in the tropics
Maria and Nate are both weakening tropical storms with just a day or two left to live as they move northeast over cold waters. The rest of the tropics are quiet.

Jeff Masters

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401. Jedkins
9:38 PM GMT on September 09, 2005
Hurricane gordon went just offshore the NC outerbanks,than did a figure - eight came back and made landfall just a bit south of melbourne loo
400. WillJax
9:34 PM GMT on September 09, 2005
Just saw a good radar loop on local jacksonvilel television news. Her recent movement has most definitely been near due east maybe ENE, though her earlier movements were certainly NE.

John Gaughan, local tv meteorologist, also said the jacksonville are needs to see thie storm rise above 32N before we can relax.
Member Since: September 7, 2005 Posts: 0 Comments: 33
399. WillJax
9:23 PM GMT on September 09, 2005
Yup guys, I'm going to early dinner. See ya around here later.
Member Since: September 7, 2005 Posts: 0 Comments: 33
398. leftyy420
9:20 PM GMT on September 09, 2005
all right i will be back in a lil bit. stormjunkie if ur still here i will leave the lobby open for you to join in when u get done doing what u need to do
Member Since: August 24, 2005 Posts: 35 Comments: 1987
397. rgeer68
9:19 PM GMT on September 09, 2005
That is some def dry air, humidity only 38% @ 5:20pm here in Knoxville, TN.
396. leftyy420
9:16 PM GMT on September 09, 2005
a early landfall would be nice. would not make my wife miss much work and use to much pto casue i have jurry duty in nov so she will have to take time off than
Member Since: August 24, 2005 Posts: 35 Comments: 1987
395. leftyy420
9:14 PM GMT on September 09, 2005
thats fair jed. we will see with the next recon vortex message and so forth. i am bout toi get up gotta clean up and eat and start to make plans to leave out this weekend
Member Since: August 24, 2005 Posts: 35 Comments: 1987
394. Jedkins
9:13 PM GMT on September 09, 2005
Well there has been dry air around it for a while now and it is fighting the dry air better than ever now,it seems a bit less likely for that to occur
393. Jedkins
9:12 PM GMT on September 09, 2005
Not really, butI may disagree on the current movement so I will not fight like a child but I will say that there has been a definate more east - notheast motion.
392. Eyeonyou
9:11 PM GMT on September 09, 2005
Ophe's due for a shot of dry air.

Link

Thats gonna leave a mark.
391. Hawkeyewx
9:09 PM GMT on September 09, 2005
It sure wish the models sites would get rid of that stupid LBAR model, if not a couple others as well. The latest LBAR puts Ophelia in the eastern Atlantic in 5 days for crying out loud... ridiculous. All that does is make the other better models so damn small it looks like a giant ink blot.
Member Since: July 5, 2005 Posts: 2 Comments: 1924
390. leftyy420
9:09 PM GMT on September 09, 2005
well sc or farther north. its cool with me. i will be leaving sunday morning or so to chase this monster
Member Since: August 24, 2005 Posts: 35 Comments: 1987
389. Weatherwatcher007
9:07 PM GMT on September 09, 2005
The track has been shifting too much. When there is a consistent landfall sanario shown by the models on SC and the NHC agrees, then I will begin to believe a SC landfall is going to happen.
388. CybrTeddy
9:07 PM GMT on September 09, 2005
It looks possibly like it's trying to loop now. Or that could be a lot of thunder tops blowing up on the south side of the storm?
JenD
Member Since: July 8, 2005 Posts: 259 Comments: 24468
387. leftyy420
9:06 PM GMT on September 09, 2005
jed, i don'tknow what ur seeing. i am looking at a loop that is 20 mins old if that and i see no motion but ne. she has not changed from that motion all day
Member Since: August 24, 2005 Posts: 35 Comments: 1987
386. Jedkins
9:06 PM GMT on September 09, 2005
There is a eye developing and the storm is expanding at a pretty high rate,
385. Jedkins
9:05 PM GMT on September 09, 2005
Look,currently it is beginning to move almost due eas,it will have to jump north ver fast or else it has already missed the forecast positions,but REMEMBER how hard this one is to predict and no one here should be certain at ALL where it will go,in fact I am not going to make predictions anymore I am going to wat and see with this one,this is more of a storm to track rather than forecast.
384. leftyy420
9:02 PM GMT on September 09, 2005
ok just checked it. its about 500 miles and an 8 hours drive. not to bad at all. wow this is going to be awsome.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
383. Weatherwatcher007
9:00 PM GMT on September 09, 2005
Yeah Stormj,

I think we could get some good winds. Is it me or is an eye developing? Maybe now the news channels in SC will take Ophelia seriously.

I think Ophelia would not weaken much, if at all due to the shear forecasts near landfall time Ophelia has been a fighter so far.
382. leftyy420
8:58 PM GMT on September 09, 2005
if u use the ramsdis link u can see the log and lat lines whick are ur pionts of refrence. she might be moving a litle east of north east but its pretty much ne.

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
381. leftyy420
8:56 PM GMT on September 09, 2005
lol i am going thats a given. will i have a shelter probly lol. nothing is stopping me i have waited 2 yesr for a chance to chase another one.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
380. weatherguy03
8:56 PM GMT on September 09, 2005
And if she keeps tracking NE tonite then N.FLa would fall to near zero as well.
Member Since: July 5, 2005 Posts: 592 Comments: 29707
379. Eyeonyou
8:55 PM GMT on September 09, 2005
I'm wit you Scotty, That loop is hypnotizing. Makes it look ENE to E.
378. Weatherwatcher007
8:55 PM GMT on September 09, 2005
I'm still not brought with the SC landfall sanario, any number of things could happen. . .
377. scottyndbfl
8:55 PM GMT on September 09, 2005
good evening everyone, and if i am not back on before landfall, i hope those in the path fair well. lefty, if you get there, i will be jealous, lol.
376. weatherguy03
8:55 PM GMT on September 09, 2005
i would put N.FLa at less then 10% chance right now...The rest of Fla. near zero.
Member Since: July 5, 2005 Posts: 592 Comments: 29707
375. leftyy420
8:53 PM GMT on September 09, 2005
i think florida is safe. she would track more north in forcast than south from what i see from the data.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
374. bullitts2000
8:52 PM GMT on September 09, 2005
Scotty, I am seeing a ene also, however the ridge behind the trof I believe is what is really going to determine landfall. Lefty do you believe FL is now definatley out of the picture? If she takes a path due east now, would the ridge behind the trof have any possibility to push her back w or wsw into FL???????????????
373. StormJunkie
8:51 PM GMT on September 09, 2005
007 I think that there is some sheer forcasted just prior to landfall. That would help in weakening, but you are not that far inland and if she ends up between Hilton Head and Chas you could see some pretty good winds up there.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
372. napleswx
8:51 PM GMT on September 09, 2005
Statement as of 5:00 PM EDT on September 09, 2005


...Ophelia regains hurricane strength...could become a threat to the
southeast United States coast...

interests from northern Florida through the Carolinas should closely
monitor the progress of Ophelia during the next few days.

371. leftyy420
8:51 PM GMT on September 09, 2005
i agree with that weatherguy
Member Since: August 24, 2005 Posts: 35 Comments: 1987
370. scottyndbfl
8:51 PM GMT on September 09, 2005
lefty, is that loop centered over the storm center? looks awful jumpy, so it is hard for me to tell. still looks a little more of an easterly component. i do not deny somewhat of a northerly component, but i just think that there is a little more easterly component.
369. leftyy420
8:50 PM GMT on September 09, 2005
caue tomm will be a busy day. i gotta lot of things i got to do befor i roll out down ur way
Member Since: August 24, 2005 Posts: 35 Comments: 1987
368. weatherguy03
8:50 PM GMT on September 09, 2005
Last possible chunk of dry air getting ready to approach storm as shortwave moves to the north of storm....Link...This may tend to halt intensification tonite for awhile but then Oph. should begin to ramp up again tomorrow...Probably close to CAT 2 by the end of the day Sat.
Member Since: July 5, 2005 Posts: 592 Comments: 29707
367. leftyy420
8:49 PM GMT on September 09, 2005
yeah thats perfect. i will do some dishes and make some lunch.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
366. Weatherwatcher007
8:49 PM GMT on September 09, 2005
I also disagree with how fast the NHC has Ophelia weakening once it makes landfall. It could hold its strength longer. I'm on alert now and ready to "hurricane proof" the house if necessary
365. StormJunkie
8:49 PM GMT on September 09, 2005
Got to run out for a few Lefty, but I will be back in about an hour. Do it then?
Member Since: August 17, 2005 Posts: 26 Comments: 16874
364. StormJunkie
8:48 PM GMT on September 09, 2005
Man-Those troll alerts work great! Everyone seems to cooperate with them well.lmao.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
363. leftyy420
8:48 PM GMT on September 09, 2005
sj u want to get in that lobby for a bit?
Member Since: August 24, 2005 Posts: 35 Comments: 1987
362. napleswx
8:47 PM GMT on September 09, 2005
She's a cane again.
361. leftyy420
8:47 PM GMT on September 09, 2005
yeah, i always like the gdl, she was out to lunch earlier in the week but she came back like i knew she would
Member Since: August 24, 2005 Posts: 35 Comments: 1987
360. StormJunkie
8:46 PM GMT on September 09, 2005
That is what I was noting about the consistency of the GFDL. I know it was stubborn on that FL crossing for a while, but it has always shown the small loop with a faster pace and GA/SC landfall. That consistency is the only thing that tends to lead me to believe that it may be the most trustworthy with this storm. Although the Ukmet and Nogaps have been pretty decent also. The GFS is just a flip flopper right now. This is all speculation on my part.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
359. leftyy420
8:45 PM GMT on September 09, 2005
yeah sj, later we gotta get those issues out of the way
Member Since: August 24, 2005 Posts: 35 Comments: 1987
358. leftyy420
8:45 PM GMT on September 09, 2005
scott its very clearly ne. here is a good sat img and you can see she is clearly moving ne


Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
357. leftyy420
8:44 PM GMT on September 09, 2005
doesn'tmatter if she does a loop or not. i be right in the middle of her looking up lol
Member Since: August 24, 2005 Posts: 35 Comments: 1987
356. scottyndbfl
8:43 PM GMT on September 09, 2005
is the appearant ene motion over the past hour or so a wobble or a turn? i know the adv says ne @ 7, but i cant help but think that it is now more of a ene if not more e.
355. StormJunkie
8:43 PM GMT on September 09, 2005
Lol. Eye. Monday won't work. She's a lady Eye she sets the date!
Member Since: August 17, 2005 Posts: 26 Comments: 16874
354. leftyy420
8:42 PM GMT on September 09, 2005
lol yeah. i was suprised all the modles now follow the gfdl which was the fastest of all the models and now looks like a good bet.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
353. Weatherwatcher007
8:41 PM GMT on September 09, 2005
Well well. . .

Ophelia is now forecasted NOT to do the loop, instead it is forecasted to nove ne and then wnw into SC. This COULD be a potential major landfall along the SC coast. GA and NC should still watch out. Until the models are consistent and clustered, it could go almost anywhere. I may agree with the NHC track but I'm not sure about the sudden northward turn after it makes landfall. I think it will move pretty far inland before it turns north.
352. CybrTeddy
8:41 PM GMT on September 09, 2005
Good at least we will know sooner than later what Ophelia will do. She has been around forever it seems already. lol
I am not making any predictions till Jim Cantore is placed into an area.
Member Since: July 8, 2005 Posts: 259 Comments: 24468
351. Eyeonyou
8:41 PM GMT on September 09, 2005
Monday is not going to work for me, I need a few more days.

Yesterday we were looking at a week.

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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