Isaac approaching hurricane strength

By: Angela Fritz , 9:14 PM GMT on August 27, 2012

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Isaac is walking the line of hurricane status this afternoon after a hurricane hunter mission investigated the storm and found winds of 80+ mph with the SFMR instrument, which looks down at the surface from the plane and estimates what wind speeds are. This instrument has a notoriously rough time in doing so when there's heavy rain, and since the strongest winds were recorded coinciding with the strongest rain, you can imagine that this region of high wind speed could be suspect. The hurricane hunter mission is still in the storm, so I imagine they will issue a special update if needed. Currently the best estimate of wind speed within the storm is 70 mph. Isaac's pressure has been dropping today as well and is now 981 mb. Isaac is moving northwest at 12 mph--no change since this morning. Satellite loops show that Isaac remains large, though asymmetric, with most of the strong thunderstorm activity on the west and southwest side. Isaac's southeast side continues to struggle with dry air and wind shear, which could help to moderate Isaac's intensity as it approaches the coast.

An oil platform in the northern Gulf of Mexico is reporting sustained winds from the north-northeast at 40 mph this afternoon. A buoy west of Tampa, Florida is recording sustained winds around 30 mph, and platforms south of Louisiana are recording winds from 35-40 mph. The widespread heavy rain of yesterday has lightened up in Florida, but a strong line of thunderstorms in one of Isaac's outer bands is training northward along and offshore of the east coast of Florida, affecting everyone from Miami to Jacksonville.

This afternoon the AP reported that Isaac's death toll in Haiti jumped to 19, which puts Isaac's total death count at 21. It appears most of the deaths in Haiti were due to collapsing structures.


Figure 1. Satellite imagery of Tropical Storm Isaac around 3pm EDT on Monday.

Track forecast:
Models seem to be coming into better agreement today on where Isaac will make landfall, closing in on Louisiana and New Orleans as most likely landfall point. The ECMWF, HWRF, and UKMET all suggest New Orleans as the landfall location. The GFS is only slightly west of that. The GFDL is the farthest west, predicting landfall near the Louisiana-Texas border. Landfall timing remains Tuesday night. Beyond landfall, Isaac is expected to move north toward the Midwest through the rest of this week, however, models are showing that the system will likely slow down around landfall time, prolonging impacts like surge and inland flooding.

Intensity forecast:
The closer Isaac gets to landfall without having formed an eye, the better it is for intensity at landfall. Isaac has strengthened only modestly in the past 24 hours, and is still struggling with a less-than-conducive atmospheric environment. The HWRF remains on the high end of the intensity spectrum, suggesting Isaac will be a weak category 2 upon landfall. Other models suggest it will be a strong category 1, but the difference is splitting hairs. The National Hurricane Center's official forecast is for Isaac to continue strengthening over the next day, reaching category 2 at landfall.


Figure 2. Tide gauge data from St. Petersburg, Florida. The green line shows the storm surge. As Isaac's counterclockwise winds blew offshore this morning, water levels feel two feet at St. Petersburg. The winds switched to onshore this afternoon as the center of Isaac moved more to the northwest, bringing a storm surge of two feet to the city.

Storm surge observations from Isaac
This morning, as Isaac's counter-clockwise winds brought offshore winds to the Tampa/St. Petersburg area, ocean waters fell two feet along the coast. This afternoon, winds have shifted to blow onshore, and a two foot storm surge has been observed at Naples, Fort Meyers, and St. Petersburg on the west coast of Florida. Water levels have also begun to rise along the coast of Louisiana, with a storm surge of 1.5 feet already occurring at Shell Beach on the east side of New Orleans in Lake Borgne.

Angela and Jeff

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1104. drj27
Quoting HCW:


Sorry you cheer for the wrong team :) Now back to Isaac
Lmao WDE 5 days
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Quoting TreasureCoastFl:
Does it not look like the storm split in two and the right part went NE over Fl and left is now going NW? That animation is so strange to me.. I've never seen part break off and go in the other direction like that. Maybe I am not understanding what I am looking at?


The split part over FL has been separated by a injection of dry air... that's why it looks like that...



We have to remember that an Eye of an hurricane is

The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area, typically 30 65 km (20 40 miles) in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the second most severe weather occurs. The cyclone's lowest barometric pressure occurs in the eye, and can be as much as 15% lower than the atmospheric pressure outside the storm.[1]
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1101. sar2401
Quoting TomballTXPride:
Now this can be a huge problem. For anyone.

Glad the NHC includes this graphic now in their forecast package.



Yeah, and the earlier graphic showed a pinpoint of 18.40 inches over Mobile and adjacent MS. It's now gone. I don't believe those graphics any more than I believe most of the other models at this time.
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1100. HCW
Quoting drj27:
I would


Sorry you cheer for the wrong team :) Now back to Isaac
Member Since: August 10, 2002 Posts: 0 Comments: 1409
Quoting JrWeathermanFL:
It seems that Isaac is mixing out a little dry air and that he might be trying to tighten up a little.
Isaac is not dying.
He's taking his time.


He is saturating that environment on his north/east.

He's got all night to make another run at an eyewall..
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Quoting Caner:


Well in fairness, that was could seeding to create clouds... Which was wholly ineffective...

Could seeding to dissipate storms by chemically forcing cooling and thereby precipitation has been absolutely effective.

The Chinese have been actively, (and frighteningly), using it hundreds of times a year> they have a several billion dollar weather modification program; with which they claim many public successes:

Link


Here's an interesting tidbit from the first hurricane ever seeded in 1947:

The hurricane was noted for the first time hurricane seeding was conducted in the Atlantic basin by the United States Weather Bureau through an operation called Project Cirrus. A B-17 dropped 80 pounds (36 kg) of dry ice onto the storm from 500 feet above its cloudtop after it had moved 350 miles off Jacksonville. Shortly afterward, the storm reversed course and headed for Savannah. The scientists conducting the experiment believed they had caused this change, but it was shown a 1906 hurricane had followed a similar pattern.[

It's comical to think now that seeding would cause a track change, but that's just how much our understanding of tropical systems has come since 1947.
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Quoting WXGulfBreeze:


He's running out of time.


Per NHC, Isaac has 36 hours over water. Has enough time to become a Category 1.
Member Since: July 8, 2005 Posts: 259 Comments: 24457
Quoting sar2401:


Looks like a giant kidney bean. :)

...or a bloated tourist on a cruise ship who has been stuffing himself with food and booze ever since the Antilles.
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Quoting SavannahStorm:


Some of the models a few days ago had shown a weak shortwave slitting off Isaac and moving up the east coast. It's probably a frontal boundry formed from a moisture channel with the Atlantic side. The farther Isaac moves away from the Atlantic the more that channel will split off into its own front.
That's pretty cool. Never seen that before. It had a split personality for days and it finally broke in two.
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Quoting slavicthunder:
♫ ♫♫♫

"EYE! EYE! EYE!"

- Ozzy Osbourne


Cup filled with ice shakes in the back ground.
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1093. drj27
Quoting HCW:


Would you like a code so you have have a free year of WU with no ads ?
I would
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1091. HCW
Quoting Grothar:


Can I have a link to that ad?

All I get on here are ads for cemeteries and arthritis creams.


Would you like a code so you have have a free year of WU with no ads ?
Member Since: August 10, 2002 Posts: 0 Comments: 1409
Quoting HoustonTxGal:


I sure hope it does not become all commercialize now the TWC has it's mitts in it.


Hmm... you don't think it has already Bain commercialized, do you?

LINK
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Quoting WeatherfanPR:
I'm the only brave here LOL come on it's just a poll !



I cry easily;)
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1088. GetReal
Eye is in radar range.

Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting JrWeathermanFL:

He's taking his time.


He's running out of time.
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1086. Caner
Quoting Dakster:



Where is cyclone buster when you need him...


Well in fairness, that was could seeding to create clouds... Which was wholly ineffective...

Could seeding to dissipate storms by chemically forcing cooling and thereby precipitation has been absolutely effective.

The Chinese have been actively, (and frighteningly), using it hundreds of times a year> they have a several billion dollar weather modification program; with which they claim many public successes:

Link
Member Since: Posts: Comments:
1085. Grothar
Quoting mitthbevnuruodo:


Commercialized would be PAID ads. So would have nothing to do with bias, but everything to do with who will pay to put ads on. Here in the UK, WU's loaded with cheezy ads for '1 trick to look years younger' or cheezy life insurance ads...just saying


Can I have a link to that ad?

All I get on here are ads for cemeteries and arthritis creams.
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Quoting slavicthunder:
♫ ♫♫♫

"EYE! EYE! EYE!"

- Ozzy Osbourne
Funny!
Member Since: August 16, 2007 Posts: 0 Comments: 397
1082. HCW
Quoting sar2401:


You're on. Landfall is somewhere from the mouth of the MS river to the LA/TX border. Seriously, mail me if I'm wrong and I'll donate $10 to your favorite charity.


I will you can donate the money to Portlight for me :) If you have watched the TVCN line for the last 2 storms The NHC has always moved the official track in 1 or 2 advisorys to match it
Member Since: August 10, 2002 Posts: 0 Comments: 1409
1081. alex14
Just looked at a close up image and there is an eye now showing that just popped up last frame.
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Looking good still.

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Everybody welcome the East Pacific's tenth named storm, Tropical Storm Ilena.

EP, 09, 2012082800, , BEST, 0, 153N, 1072W, 40, 1000, TS, 34, NEQ, 40, 30, 0, 30, 1006, 200, 40, 0, 0, E, 0, , 0, 0, ILEANA, M,

Member Since: July 6, 2010 Posts: 113 Comments: 32505
Quoting SavannahStorm:


Some of the models a few days ago had shown a weak shortwave slitting off Isaac and moving up the east coast. It's probably a frontal boundry formed from a moisture channel with the Atlantic side. The farther Isaac moves away from the Atlantic the more that channel will split off into its own front.


yeah thats the remnants of the trough from a few days ago...still just enough divergence plus enhancement from isaac is causing all that rain off the SE coast moving towards the coast that why the Ga and coastal carolina coast will see that rain in the preceip forecast on the blog
Member Since: August 4, 2010 Posts: 0 Comments: 572
Quoting Dakster:



Where is cyclone buster when you need him...

I was thinking of the click and drag option...
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Good sat loop showing what is occurring with Isaac right now.

Link
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Quoting SavannahStorm:


Some of the models a few days ago had shown a weak shortwave slitting off Isaac and moving up the east coast. It's probably a frontal boundry formed from a moisture channel with the Atlantic side. The farther Isaac moves away from the Atlantic the more that channel will split off into its own front.
hmm Ive never seen that before with a Tropical Storm. Pretty cool. Thanks
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1074. sar2401
Quoting Chicklit:


Looks like a giant kidney bean. :)
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Quoting greene47:


Actually Eglin evacuated for Ivan and Dennis...we were 12 hours from the order for Katrina as well...I agree why on earth would they mass evac for Issac..lol..
I'm assuming they would evacuate all non-necessary personnel from Keesler... that seems to be the only military base where an evacuation seems necessary...
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♫ ♫♫♫

"EYE! EYE! EYE!"

- Ozzy Osbourne
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Quoting Chicklit:
Meanwhile, my son and his family are in South Korea expecting Bolaven. He thinks they're prepared.
It should be a CAT 1 at landfall.
And the 28th is his 28th birthday.
Lot goin on...sigh


Praying for their safety. I have sons 30, 28 and 21. Know what you're going through. (I'll toss your name in there for good measure.)
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Quoting TreasureCoastFl:
Does it not look like the storm split in two and the right part went NE over Fl and left is now going NW? That animation is so strange to me.. I've never seen part break off and go in the other direction like that. Maybe I am not understanding what I am looking at?


Some of the models a few days ago had shown a weak shortwave slitting off Isaac and moving up the east coast. It's probably a frontal boundry formed from a moisture channel with the Atlantic side. The farther Isaac moves away from the Atlantic the more that channel will split off into its own front.
Member Since: Posts: Comments:
Quoting keithneese:
Very light rain falling here near Tillman's Corner in Mobile now.
Cool but no rain right now on Old Shell at mcGregor
Member Since: August 16, 2007 Posts: 0 Comments: 397
1067. sar2401
Quoting HCW:


That line has been money and the NHC follows it. $10 :)


You're on. Landfall is somewhere from the mouth of the MS river to the LA/TX border. Seriously, mail me if I'm wrong and I'll donate $10 to your favorite charity.
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1066. Caner
Quoting Bielle:


Perhaps you enjoy "fruit loop kook sites" that promote dangerous weather theories. My concern was that anyone might be directed there from here (which is generally considered to be a scientific and sane site) and take that site seriously because of the connection. Please understand, as nutty as that place seems to you and me, there are people who believe, totally. So, to me. that link is much worse than most spam. (And kook sites frequently have nasty tracking and/or other malware that one might drag back inadvertently.)


Naw, just going over the board rules, i didnt see any particular ban in place on kooky sites that promote weather theories i don't personally believe... The rules were limited to not obscene and weather related.

I just didn't think it was worthy of a report... But to each their own.
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1065. Dakster
Quoting unknowncomic:
They tried cloud seeding back in the 60's. They gave up on that.



Where is cyclone buster when you need him...
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Quoting airmet3:


Yes. Mother Nature has a remarkable ability to take care of herself.


yes and after about 5 more years there will be a lot less hurricane because heat will not need to be distributed to the poles as it will heat itself just like land/water without ice does
Member Since: August 4, 2010 Posts: 0 Comments: 572
Quoting TomballTXPride:
Now this can be a huge problem. For anyone.

Glad the NHC includes this graphic now in their forecast package.

I'm having a hard time understanding that rain model, at least that random blob for GA. (Not that I don't appreciate the idea of lots of rain here.)

I'm just not seeing it based on the modeled track and the storms current behavior. I guess it could be the blob off Florida's east moving NW but that makes little sense given the setup. Most such orphaned blobs off the coast continue up along the coast and out. Coming in along N. or even S. Carolina. Isaac doesn't seem to want to pull it along with him and steering doesn't seem to be setting up to push it inland either.

Weird.
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Quoting mobilebayal:




C. Scared to say for fear of bashing
I concur with the C vote
Member Since: August 16, 2007 Posts: 0 Comments: 397
Quoting airmet3:


Please read Angela's blog post. Pretty much sums it up.


I read it when it came out '4 hrs ago'. Thank you
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last chance for a dmax...get your S*** together isaac! at least its slowed down! but then again its just churning up colder water so its basically a win/lose cituation that should keep it steady with less than a 10mph strengthning
Member Since: August 4, 2010 Posts: 0 Comments: 572
Quoting waterskiman:

You know your on a lib site right. In the old days it didn't matter and that was four years ago


Last comment on this: the advertisements you see on any website other than very specific politcal sites are determined by the ads paid for and your own cookies. Since it is an election year, you are seeing many political ads. These ads are probably not bought from a particular site, but from an agent that has a portfolio of sites. There is no reason to think anyone on the site is critical of your own dearly held political beliefs.

I look forward to learning more about weather in the future.
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It seems that Isaac is mixing out a little dry air and that he might be trying to tighten up a little.
Isaac is not dying.
He's taking his time.
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Quoting sunlinepr:
Does it not look like the storm split in two and the right part went NE over Fl and left is now going NW? That animation is so strange to me.. I've never seen part break off and go in the other direction like that. Maybe I am not understanding what I am looking at?
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1055. Caner
Quoting wxpaladin:
In short Cancer, the answer to your question is yes. Trop Cyclones are heat transports that distribute excess stored latent heat from the oceans and then distributes that energy poleward.


So much for "flimsy conjecture" about 'weather' relating to 'climate'...

80)
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1054. HCW
Quoting sar2401:


How much you wanna bet? :)


That line has been money and the NHC follows it. $10 :)
Member Since: August 10, 2002 Posts: 0 Comments: 1409

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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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