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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1704. DFWjc
Quoting MrsOsa:



The XTRP is not a forecast model. It simply shows where the storm would go if it stayed going in exactly the same direction that it is now.


Thank you MrsOsa!!
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Sure wish Storm would show up again
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Quoting IcemanMC:
Glad to see some oldies taking up for one old members; Patrap missing all the fun with IsaacQuoting IcemanMC:
Glad to see some oldies taking up for one old members; Patrap missing all the fun with Isaac



Where is patrap???? Long time lurker and missing him.
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1701. MrsOsa
Quoting jake436:
I started lurking here in 2004. Joined in 2006. Posted quite a bit for quite a while, but finally just went back to lurking. I lurked for so long I forgot my username...lol. Jake was my dog for 13 years, died in 2009. I had forgotten I used his name in my username. Finally remembered yesterday. Whatever happened to Hurricane23...Adrian? I know Patrap still posts, but where is he at the moment?



He picked a fine time to take vacation!
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1700. Walnut
Quoting Orcasystems:
Ummmm not to be a tad on the alarmed side... but 983-981-980-979 in 2.5 hours....
Yeah I was thinking that too... the northern side is still pretty eroded though. If this deepens any further, there is a good chance the convection can get wrapped back around and storm could regain some symmetry but looks like time is quickly running out.
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1699. JeffM
Quoting kmanislander:
Good evening folks.

979 mbs and still no upgrade ??


Please make some darn sense of this for us Kman!!
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Quoting JeffM:


Remember the whole Lefty's wave and StormTop nailing Katrina? Cannot believe it's been 7 YEARS!


Jeez, I remember StormTop. Seem to remember controversy about someone spoofing his name or something... Man... Katrina seems like yesterday - and here we all are. Y'all don't remember me - I was a lurker - but I remember you. Hope life has treated you well.

i know this isn't a chat blog... I'm just really tired from hurricane prep and have more to do early tomorrow.. just winding down and taking a breath, here in Lafayette, La.
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1697. will40
Quoting hahaguy:


Seems quite odd.



he is just so large he is having a time getting the winds up
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I'm in Milton, Fl standing outside looking up at the sky. The northern bands of Isaac have come for a visit. It's pretty cool to watch the clouds just fly by. The ones higher up in the air aren't doing anything, and there's moonlight.. so it's easy to see the contrast.

Winds are at about 15kt max. I'm hoping it stays that way. People are very fortunate that this thing has remained a TS this long. If it makes it to Hurricane strength, I'll be surprised at this point.

Remember how people were saying this was Katrina II yesterday?
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Quoting hahaguy:


Seems quite odd.


Indeed it does. It seems that the winds just cannot respond due to the lopsided structure of the system combined with periodic dry air ingestion.

Perhaps another year where either dry air or shear continously prevents the storms that do develop from intensifying significantly. I still believe that we will see a hurricane from this one though.
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Quoting TampaFLUSA:
GFS running.


How are the bay waters where you are at? We are close to flooding here in St Pete
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Quoting kmanislander:
Good evening folks.

979 mbs and still no upgrade ??


Hey, Kman! Will you straighten this all out, please? TIA :)
Member Since: July 9, 2006 Posts: 184 Comments: 29594
Quoting moonlightcowboy:


I'm just an ol' poke, so don't go by what I yak about really. Just an old hobby. Isaac's presentation is improving, getting stronger. He's punched all he can out of getting more northwards without strengthening. Present intensity, weaker, Morgan City would definitely be a candidate for landfall.


Thanks got you...
Member Since: June 16, 2006 Posts: 0 Comments: 1560
1691. Thrawst
Quoting Bobbyweather:

If you see a previous comment, you'll see that TS Leslie of 2000 had a lower pressure, 973 mb.


Checking Wikipedia, it says 1006mb for that storm o.O
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greetings people. Been a hot minute since I've been in here.

Glad to see everyone keeping an eye on stuff!
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1689. scott39
Quoting kmanislander:
Good evening folks.

979 mbs and still no upgrade ??
Too big for his britches!
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1688. jake436
I started lurking here in 2004. Joined in 2006. Posted quite a bit for quite a while, but finally just went back to lurking. I lurked for so long I forgot my username...lol. Jake was my dog for 13 years, died in 2009. I had forgotten I used his name in my username. Finally remembered yesterday. Whatever happened to Hurricane23...Adrian? I know Patrap still posts, but where is he at the moment?
Member Since: August 31, 2006 Posts: 0 Comments: 271
1687. DFWjc
Quoting oracle28:



Give it time, the XTRP will shift east sooner or later.


I only SMH, because with all the road construction going on here, we don't need anymore rain right now...
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Quoting Beachfoxx:
Cowboy -
That is a fine avatar you have... and great song you got playing!

So good to see everyone!!! : )

Dry air is our friend... Looks like the FL panhandle has been spared the worst of Isaac & to think 3 days ago we had a big bullseye painted on us!

Still watching & hoping our friends to the west come out o.k. : )



BeachFox, no, yours is one dayumed fine-looking avatar! ;)
Member Since: July 9, 2006 Posts: 184 Comments: 29594
Quoting Thrawst:
This has got to be the lowest pressure ever recorded for just a tropical storm.


Nope Leslie of 2000 had pressure of 973mb
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Do anybody remember a crazy guy waiting for a landfall in a jeep and a camera pointing to a umbrella or gas station canopy. Somebody remember the name??? am pretty intrigued ,maybe he would pull that stunt again. Not pretty smart or hurricane savie ..but really funny to listen to.
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TV news from many local and mainland "en espanol" and english channels affirm Isaac will make landfall as a Cat2.... Real or an Exageration looking to sell goods?



Has to consolidate the northen quadrant....
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Pressure continues to drop, but the storm continues to be flayed on the northern half.
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...
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1680. will40
Quoting AllyBama:
Dance? me? ROFL..

MLC, such a nice thought but...lol

Will - a pole? HAHAHAHAHAHA!

Will, I know! things could have been much worse for you and others - glad they weren't and hope nothing comes your way this year for sure!



ty ALLY i hope you will be safe also and yes i said get da pole lmao
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Ummmm not to be a tad on the alarmed side... but 983-981-980-979 in 2.5 hours....
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting jake436:
Guys, Taz has been Taz here since long before I joined the blog. It used to drive me nuts too, but you get used to it. He's the resident...er...Taz. Take it with a grain of salt.

Quoting truecajun:
right. like the little Tazmanian Devil. just picture that whenever you read his posts. he's fun



Imagine everybody accepting most everybody else just as they are. What a concept! :-)


I don't know what TWC folks were thinking, sending Jim Cantore to New Orleans. (And I say this as a fellow Vermonter!) We're still recovering from Irene, one year ago tomorrow. August 28th is an infamous day for hurricanes hitting land.

Hope everyone comes through okay. Isaac has already claimed too many lives.



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1677. hahaguy
Quoting kmanislander:
Good evening folks.

979 mbs and still no upgrade ??


Seems quite odd.
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1676. JeffAt
Quoting Orcasystems:


Drop it or leave.. your choice.
To many people like Taz... its a dangerous little icon to pick on.



Ditto!!! I usually lurk. I don't know a lot about these storms to post much. But I do know I have learned so much from Taz and the others defending him than I have this season for sure.
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Quoting DFWjc:


How much deeper are the Levees now? Are the gates to block more water coming into the Lake?


And I know I lost 10 ibs putting stuff up the last 2 days and boarding windows
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1674. Thrawst
This has got to be the lowest pressure ever recorded for just a tropical storm.
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Quoting Beachfoxx:
Who'd thought we would be "lurkers"? LOL
Lots of years and lots of storms and here we are - still together after all these years.
Hey, is there a song in there??? LOL


Lol I thought about that the other day...I lurk more now than I ever did back then. But it's awesome to have so many bloggers still sticking around and making this community great after 8 hurricane seasons.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
I love Taz!
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1671. will40
Quoting GeauxGirl:


Doesn't the GFS run soon? The toothpicks are hurting my eyelids, but I can't remove them until I see another GFS run. ;-)



yes it is running now
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Good evening folks.

979 mbs and still no upgrade ??
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1669. will40
XTRAP is never wrong
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Cowboy -
That is a fine avatar you have... and great song you got playing!

So good to see everyone!!! : )

Dry air is our friend... Looks like the FL panhandle has been spared the worst of Isaac & to think 3 days ago we had a big bullseye painted on us!

Still watching & hoping our friends to the west come out o.k. : )
Quoting moonlightcowboy:



Oh, hell yeah! ;)

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I'm a long-time lurker - trying to remember when I found this blog...I remember now.... I joined 7 years ago tonight... different screen name, with an e-mail account lost to time. Cannot believe it's been 7 years since Katrina. Seems like yesterday - and a lifetime ago.

I think Taz wuz here, too.
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Dance? me? ROFL..

MLC, such a nice thought but...lol

Will - a pole? HAHAHAHAHAHA!

Will, I know! things could have been much worse for you and others - glad they weren't and hope nothing comes your way this year for sure!
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1665. scott39
Looks like Isaac is breaking off a chunk of himself from the East Coast of Fl.
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Quoting oracle28:



Give it time, the XTRP will shift east sooner or later.


Doesn't the GFS run soon? The toothpicks are hurting my eyelids, but I can't remove them until I see another GFS run. ;-)
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Folks! LOOOONG time lurker before I even joined. I really don't care when you all bicker but I really hate when a voice is silenced because it doesn't agree with the majority. trust me I geared a lot of my preps on Levi,'s thought process. Taz also put up a lot of info as well as Largo and Grotho.


my point is......can't we all just get along?!?!

Seriously different opinions and back up is why it helps a lot of us that don't know as much as you guys and makes us research. Right now I am very very afraid for my disabled father in law in Nola and trying to make decisions on his behalf, place yourselves in my shoes.. Trying my best to make the impossible decision with a cantercous stubborn family member who is no many miles away I can't get to.

That being said I am glad for all of you, you all are a god send in the sea of misinformation.



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Quoting nola70119:


Sure, just confused, if you had said takes Alabama out of the picture I would have understood. So you think that Morgan City is not possible based on that map? Just curious why?


I'm just an ol' poke, so don't go by what I yak about really. Just an old hobby. Isaac's presentation is improving, getting stronger. He's punched all he can out of getting more northwards without strengthening. Present intensity, weaker, Morgan City would definitely be a candidate for landfall.
Member Since: July 9, 2006 Posts: 184 Comments: 29594
1661. zillaTX
Quoting TampaFLUSA:
GFS running.


expect any changes?
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Quoting taco2me61:
Hey Mobilebay :o) I'm back :o)
looks like MS maybe back in the Mix again :o(

Taco :o)


Hey Taco! I will keep my fingers crossed for Mississippi....I guess that means us since Mobile Bay is in Mississippi :)
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1659. jake436
Quoting oracle28:



Give it time, the XTRP will shift east sooner or later.
:)
Member Since: August 31, 2006 Posts: 0 Comments: 271
Quoting nola70119:


Pascagoula is in Mississippi....

But everything East of Pascagoula is in Al, except for Mobile, because TWC was reporting from Mobile, MS this afternoon!
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The anticyclone is becoming more organized. It is about 7/8th complete now. Compared to most of Isaac's life, including as recently as a few hours ago, it was only about half of an anticyclone above it.

The the anticyclone finishes developing on the north side of the storm, I would expect outflow and convection to improve greatly.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
1656. Caner
Quoting jake436:
Basically (paraphrasing), he said "this thing better be a CAT 3 when I wake up or I'm dropping a cow on the NHC". Typical Taz being overdramatized by a bunch of people that have been on here a week.


LOL. ok, i did see that... I just cant believe that's what they were up in arms... Or should i say piano wire... About...

good lord man.
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Quoting JeffM:


Remember the whole Lefty's wave and StormTop nailing Katrina? Cannot believe it's been 7 YEARS!

Sure do remember staying up all night waiting to see what happened to Katrina overnight; folks getting on the blog asking if they should evacuate and Lefty yelling at them to get off their computers, get their keys and get the heck out... amazing stuff.
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1654. will40
Quoting Orcasystems:
OMG... everyone is coming back... where is Floodman??


he was on last nite
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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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