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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One more try for some laughs:)
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Quoting MississippiWx:
Going to throw the 00z Euro in the trash for now due to how inconsistent it has been with Isaac. Add the fact that when we had Debbie with a very similar setup to now, the Euro was off then too. Would like to see the HWRF/GFDL, but they seem delayed due to the GFS being delayed. CMC was still New Orleans, UKMET was New Orleans, and GFS was New Orleans. We'll see. Euro might be picking up on something, but it's utterly frustrating to be within 24 hours of landfall and have a model shift over 200 miles to the west.
Agreed. The ECMWF had been winning with Isaac earlier on. It was calling for a central Gulf coast landfall well before any of the other models picked up on the solution. Lately, however, it has been rather inconsistent and has literally been playing catch up to the GFS. First it switched to the GFS's Panhandle solution, then the GFS flipped to Louisiana, and now the ECMWF is doing the same.

Check out the 00z GFS from last night




Check out tonight's 00z ECMWF




Intensity and track are practically identical. Good ol' game of catch up

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Quoting listenerVT:
Any chance that's a completed eyewall I see? (Mind you, I'm seeing it on an iPhone screen. LOL!)


Probably not all the way closed still...latest RECON fix from 30 minutes ago showed it being open SE to SW. He could still close it off and begin to organize faster, although he has tried this process countless times over the last 48 hours only to have the eyewall eroded away by dry air entrainment and being slightly displaced from its mid level spin.

L. Eye Character: Open from the southeast to the southwest
M. Eye Shape & Diameter: Circular with a diameter of 30 nautical miles (35 statute miles)
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Quoting sar2401:


It was even worse since the battleship Alabama was being used as the backdrop. Still, what the heck, AL and MS are only a few miles apart there, and there's really no differences between the two states...well, except for the casinos and fun stuff like that. We don't put up with any of that kind of balderdash here in AL.


Hah, forgot about that video shot! Another Katrina comparison unfortunately, if I recall the audio correctly.

With the TWC in the background I know now much more about Skin Tags and the fact that Buick still manufactures autos.

Member Since: August 23, 2012 Posts: 0 Comments: 21
2300. sar2401
Quoting TomTaylor:
Evening everyone


Hey, Tom, you starting the night shift?
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Quoting sar2401:


Keeper of the Gate says his blog is still up so apparently he wasn't banned. He may be doing what all the other sane people are doing at this hour....sleeping. :0



Thanks Keeper for checking and to you for posting this. Sorry to have mentioned it and to have caused so much distress. I allowed my concern to get the best of me.
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2298. sar2401
Quoting xtremeweathertracker:
Goodnight all, see ya later this morning!!


GN, xtreme. Have an xtremely good night/morning. :)
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Evening everyone
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Any chance that's a completed eyewall I see? (Mind you, I'm seeing it on an iPhone screen. LOL!)
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2295. sar2401
Quoting atmosweather:


Looks like an ultrasound image.



See, my ex even had that tail in utero. Wonder why I didn't notice that before I married her. :)
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2294. sar2401
Quoting CoastalAlabama:



LOL. Well said.

Especially as they report from Mobile, MS. Did you see that gaffe earlier this afternoon? I mean, good gracious, please correct yourself as you read an error on the teleprompter. Unless you just don't know any better. It's not like you are discussing an inlet off of Seattle, WA...Atlanta is down the road from MS/AL. Should know better.





It was even worse since the battleship Alabama was being used as the backdrop. Still, what the heck, AL and MS are only a few miles apart there, and there's really no differences between the two states...well, except for the casinos and fun stuff like that. We don't put up with any of that kind of balderdash here in AL.
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Quoting sar2401:
Nope, I take that back now. Isaac no longer looks like Miss Piggy on the IR. He now looks like my ex-wife. You can see that forked tail starting to form west. :)


Looks like an ultrasound image.

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Goodnight all, see ya later this morning!!
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2291. sar2401
Quoting wxchaser97:

Darn, I always like read them since they are very detailed. That is crazy though, I guess I'll get some sleep now. Night everyone.


GN, WX97.
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2290. sar2401
Quoting Kumo:


Just thinking, perhaps folks that knew him well could write the Admins some messages and request that his account be restored?

I've seen a few people that absolutely deserved to be banned in my short time on this blog, but Taz definitely was not one of them. I'm all for giving his account back.


Keeper of the Gate says his blog is still up so apparently he wasn't banned. He may be doing what all the other sane people are doing at this hour....sleeping. :0
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First recon fix was at 2:31z, if the next fix(4th)is still west that should be enough for the NHC to move thier track to the left.
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2288. drj27
Quoting CoastalAlabama:



LOL. Well said.

Especially as they report from Mobile, MS. Did you see that gaffe earlier this afternoon? I mean, good gracious, please correct yourself as you read an error on the teleprompter. Unless you just don't know any better. It's not like you are discussing an inlet off of Seattle, WA...Atlanta is down the road from MS/AL. Should know better.



Lol
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2287. sar2401
Nope, I take that back now. Isaac no longer looks like Miss Piggy on the IR. He now looks like my ex-wife. You can see that forked tail starting to form west. :)
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2286. Kumo
Quoting TexNowNM:



Unfortunate situation resulted in a post being made earlier tonight asking everyone to report Taz and get him permanently banned. There were a few who agreed and he has not posted since. Proud to say he had many defenders.

Also, I'd like to add you have posted some really interesting tidbits of information.


Just thinking, perhaps folks that knew him well could write the Admins some messages and request that his account be restored?

I've seen a few people that absolutely deserved to be banned in my short time on this blog, but Taz definitely was not one of them. I'm all for giving his account back.
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Quoting NCHurricane2009:

I am thinking I'll have it done by 3:30 AM...to be honest I am shooting more for the sunrise or morning crowd.

Sorry...I tried to do the update before 11 PM...but I come exhausted from work and crash....and end up staying up in the morning. Like last week...all my blogs were released at 6 AM...then I'd go to work right after I released my blog...isn't that nuts? LOL

Darn, I always like read them since they are very detailed. That is crazy though, I guess I'll get some sleep now. Night everyone.
Member Since: March 16, 2012 Posts: 127 Comments: 7948
Quoting sar2401:


Uh oh, you're still under a tropical storm WARNING. Those winds could jump up to 15 mph any second now. You could get something blow into your eye if you don't have the Weather Channel™ approved safety googles on. They are worn by all the Weather Channel™ intrepid "talent" that has spent so much time on beaches in their Weather Channel™ official North Face™ rain gear, roasting to death in the hot sun while waiting for the "big one" to hit. :)



LOL. Well said.

Especially as they report from Mobile, MS. Did you see that gaffe earlier this afternoon? I mean, good gracious, please correct yourself as you read an error on the teleprompter. Unless you just don't know any better. It's not like you are discussing an inlet off of Seattle, WA...Atlanta is down the road from MS/AL. Should know better.



Member Since: August 23, 2012 Posts: 0 Comments: 21
Quoting GTcooliebai:
WeatherBELL


TY GT
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Ok i may get bashed for this....BUT....the last 4 fixes..one from the previous mission and 3 from the current show a rough heading of 285 to 290 degrees!! Am i wrong...is this a jog or trend?? *Covers head and ducks*
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Well that's it for me guys be back later today. Have a goodnight all. By the way the GFS continues to insist on Kirk although weaker on this run.

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These storms are being manipulated...for seven years it has been the case. Anyone who suggests it is considered a quack or a troll or such. Either the storms are being manipulated, or present-day weather scientists are morons. Look at the forecasts for this storm, and what actually happened.
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Quoting wxchaser97:

Gordon may or may not have been, that's up to the NHC to decide. As for this years ACE, it has been pretty low for the amount of storms we've had. With this similar pattern I don't know when the next major will form. When will your blog be finished NC, I want to read it and I'm already up too late?

I am thinking I'll have it done by 3:30 AM...to be honest I am shooting more for the sunrise or morning crowd.

Sorry...I tried to do the update before 11 PM...but I come exhausted from work and crash....and end up staying up in the morning. Like last week...all my blogs were released at 6 AM...then I'd go to work right after I released my blog...isn't that nuts? LOL
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Quoting GTcooliebai:
Then again the GFS being delayed makes you wonder if it was a bad run because wasn't it going more west more in line with where the Euro now has Isaac going?


GFS was actually the farthest east it has been with Isaac.

Quoting xtremeweathertracker:


Also the GFS initiated with an unusually high surface pressure..dont know if that would affect it??!


GFS doesn't initialize on the NCEP guidance with the "actual" surface pressure.
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2277. sar2401
Quoting dixiegal1:


Hope this works, thought it might bring a few laughs;)


Nope, didn't work. Give it another try, we could all use a few laughs. :)
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So last night Isaac made a left track shift 28 degrees off of its original trajectory before turning right again nearly 33 degrees. If the current curve is one of these wobbles like last night then I would expect by the next fix (this morning) that it will have returned to roughly its original trajectory especially since it has a lopsided structure and likely an elongated eye. That imbalance can lead to a cycloid trajectory which is what I think we're seeing here tonight.

If not then there's a whole new can of worms for us to open.
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2275. drj27
Quoting sar2401:


Uh oh, you're still under a tropical storm WARNING. Those winds could jump up to 15 mph any second now. You could get something blow into your eye if you don't have the Weather Channel™ approved safety googles on. They are worn by all the Weather Channel™ intrepid "talent" that has spent so much time on beaches in their Weather Channel™ official North Face™ rain gear, roasting to death in the hot sun while waiting for the "big one" to hit. :)
Lmao that was great
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2274. sar2401
Quoting washingaway:
Recon showing west, Euro back to the west......


Let's see...I've been saying LA/TX border for three days now...we'll see. If so, there's another blogger here that's going to owe Portlight $10...although I'll probably cough up $10 in addition, just because Portlight's a great organization. :)
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Quoting GTcooliebai:
Then again the GFS being delayed makes you wonder if it was a bad run because wasn't it going more west more in line with where the Euro now has Isaac going?


Also the GFS initiated with an unusually high surface pressure..dont know if that would affect it??!
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Not posted in full yet:

000
URNT12 KNHC 280614
VORTEX DATA MESSAGE AL092012
A. 28/05:37:50Z
B. 27 deg 17 min N
087 deg 44 min W

C. 850 mb 1249 m
D. 47 kt
E. 175 deg 71 nm
F. 266 deg 36 kt
G. 174 deg 61 nm
H. 978 mb
I. 17 C / 1541 m
J. 22 C / 1524 m
K. 22 C / NA
L. OPEN SE-SW
M. C30

N. 12345 / 08
O. 0.02 / 1 nm
P. AF309 2909A ISAAC OB 14
MAX OUTBOUND AND MAX FL WIND 76 KT N QUAD 05:48:00Z
MAX OUTBOUND SFMR SURFACE WIND 60 KT N QUAD 05:46:00Z
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Quoting MississippiWx:
Going to throw the 00z Euro in the trash for now due to how inconsistent it has been with Isaac. Add the fact that when we had Debbie with a very similar setup to now, the Euro was off then too. Would like to see the HWRF/GFDL, but they seem delayed due to the GFS being delayed. CMC was still New Orleans, UKMET was New Orleans, and GFS was New Orleans. We'll see. Euro might be picking up on something, but it's utterly frustrating to be within 24 hours of landfall and have a model shift over 200 miles to the west.
Then again the GFS being delayed makes you wonder if it was a bad run because wasn't it going more west more in line with where the Euro now has Isaac going?
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Ya know i guess the Euro would follow the western most edge of the NHC cone.
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Hope this works, thought it might bring a few laughs;)
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Quoting MississippiWx:
Going to throw the 00z Euro in the trash for now due to how inconsistent it has been with Isaac. Add the fact that when we had Debbie with a very similar setup to now, the Euro was off then too. Would like to see the HWRF/GFDL, but they seem delayed due to the GFS being delayed. CMC was still New Orleans, UKMET was New Orleans, and GFS was New Orleans. We'll see. Euro might be picking up on something, but it's utterly frustrating to be within 24 hours of landfall and have a model shift over 200 miles to the west.

+1000
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Going to throw the 00z Euro in the trash for now due to how inconsistent it has been with Isaac. Add the fact that when we had Debbie with a very similar setup to now, the Euro was off then too. Would like to see the HWRF/GFDL, but they seem delayed due to the GFS being delayed. CMC was still New Orleans, UKMET was New Orleans, and GFS was New Orleans. We'll see. Euro might be picking up on something, but it's utterly frustrating to be within 24 hours of landfall and have a model shift over 200 miles to the west.
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Current NHC track:


Current drought map, help is on the way central plains/great lakes/Mississippi valley:
Member Since: March 16, 2012 Posts: 127 Comments: 7948
i imagine the storm is taken a big breathe before landfall.... right before actual landfall he'll hit 75-80 mph
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I suspect the "hype" has something to do with it having a chance early on of really screwing with the convention, plus happening to be then apparently aiming for New Orleans basically right at the anniversary of Katrina. Those were bound to get extra national attention regardless. But I don't think it's all hyping, either. I think this has looked like a storm that could become really dangerous _any minute_ for like 4 days, and has been really difficult to forecast.

NHC has done a fine job with it, one of the things that drives me kind of batty reading here is the degree to which folks seem to think that being "right" about the final outcome is (a) possible in all cases several days out and (b) necessarily means much -- you can be "right" for the wrong reasons, or be wrong for the right ones.

This stuff is complicated, it's hard to know exactly when some ridge might move or whatever. The folks doing the forecasts are looking at the data they've got and interpreting it as thoughtfully as they know how -- they may have to adjust as more data comes in, as conditions change, whatever.

The spread in the models has been really interesting, honestly -- I'd love to know what each was interpreting differently to come up with such wildly different tracks for so long. But sometimes, it really is about a difference of a couple of hours, or 50 miles this or that way over cuba. So I'm actually mostly surprised that the models agree and do well so _often_ as they do, and I'm generally surprised at how well the NHC does in forecasting these things. It's easy from here to look back and think it was overdone or poorly handled, but that's hindsight. Foresight is not nearly so simple.

All my two cents. Bed for me and likely back to lurking.
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2263. CBJeff
I know that wind speed is the marquee data point that really defines a storm, but as landfall gets closer and closer (and the window for RI gets smaller and smaller), I'd like to point out the first thing I was taught about the storm prep/emergency management business:

Wind breaks stuff; water kills.

Isaac may be punching below his weight on the wind front, but he's throwing around a decent amount of water.
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L. Eye Character: Open from the southeast to the southwest
M. Eye Shape & Diameter: Circular with a diameter of 30 nautical miles (35 statute miles)

Low level center is tightening gradually now...with 75+ kts being found at 5,000 feet I'd surely expect Isaac to manage to spin up some Category 1 surface winds pretty soon.
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2261. sar2401
Quoting drj27:
Weather Alert: reporting live from ft.walton beach the winds are blowing about 5mph I think it's time to start boarding up the windows also I would like my 2hours back that I lost from work today stay tuned for the next update as I'm sure the conditions will get worse when the winds get to 10 mph


Uh oh, you're still under a tropical storm WARNING. Those winds could jump up to 15 mph any second now. You could get something blow into your eye if you don't have the Weather Channel™ approved safety googles on. They are worn by all the Weather Channel™ intrepid "talent" that has spent so much time on beaches in their Weather Channel™ official North Face™ rain gear, roasting to death in the hot sun while waiting for the "big one" to hit. :)
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Quoting GTcooliebai:
Euro 72 hrs. into Texas and 96 hrs. into Oklahoma which would be a good thing for drought relief.


I bet the NHC forecasters are scratching their heads bald with this convoluted, discombobulated nonnsense with the models! LOL
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Quoting NCHurricane2009:

I am predicting a peak of 75 mph...tops....

And because of this....unless you think Gordon went cat 3 briefly...we have had zero...zip...notta..big goose egg # of major hurricanes in the Atlantic this season so far....amazing given the # of the storms. Goes to show that # isn't everything. I think we have a record low ACE (Accumlated Cyclone Energy) divided by # of storms...

Gordon may or may not have been, that's up to the NHC to decide. As for this years ACE, it has been pretty low for the amount of storms we've had. With this similar pattern I don't know when the next major will form. When will your blog be finished NC, I want to read it and I'm already up too late?
Member Since: March 16, 2012 Posts: 127 Comments: 7948
where u at nola I am up here in gonzales light northwesterly winds about 5mph
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Euro 72 hrs. into Texas and 96 hrs. into Oklahoma which would be a good thing for drought relief.
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2256. KEEPEROFTHEGATE (Mod)
looks like its still moving forward


lol sorry had to do it
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Quoting washingaway:
Recon showing west, Euro back to the west......


Yeah looks like Euro has it going thru DFW then on into Oklahoma....if that pans out thos folks through that country and into Arkansas could really use the precip.
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Are you saying Euro West and GFS East?
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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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