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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Quoting HoustonTxGal:


I DID NOT CREATE IT... I was only sharing for those who might like to see it.. Trust me, I have o desire for the storm to come to TX.

We can dream
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Been lurking for the past year on this site. Signup last night after hearing some floridians tell their stories. Good to see some other Palm Beach County bloggers. The "tail of Isaac" has been the "tale" of the story here today. I noticed it last night over cuba and western haiti but had no clue it would linger around today and dump so much rain on us. Lived in florida my whole life, never have I seen so much rain. Staying at my enlaws right now because my road is flooded and it is a mile hike to where I live. I teach and my school has flooding issues, this supposedly a shelter in palm beach county. Close to 20 inches of rain near Royal Palm Beach and Loxahatchee.
I have learned so much from the great blogging conversations over the past year. Could do without some of the wierd drama between bloggers but I have learned from the most respected bloggers(levi, grother, tropicalanylysis, etc) and the not so respected or educated aswell. I find my self trying to make objective observasions but often find my self fighting my own "wishcasting".
My take on Isaac is that he has been fighting the dry air from his genesis. Even tonight he looks like he is trying to cough it out. Crazy to consider that towns closer to the storm "west cost of florida" have had 1/10 of the rain of towns 2 to 3 hundred miles away from the center. Looking forward to more learning and occassionally posting,
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Quoting Pirate999:


ahh.. cough cough.. 320 miles is not quite "landing". Agree the direction and landfall but please, had a drink.. scotch or vodka? mm.. speaking of, isn't it martini time?
vodka or gin? I can't decide, so one of each it is.
Member Since: August 16, 2007 Posts: 0 Comments: 397
Quoting washingtonian115:
Where are all the people that were bashing me this morning at?


what were you getting bashed for?
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Isaac is going to moisten up that East side. He looks to be barley moving NNW.....that is not good!
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Definitely a levee-tester the next two to three days. I think it will close off the NE quad overnight during DMAX. Looks to be slowing down some as well.
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Quoting katadman:
Howdy, MLC.


Evening, Katadman! Good to see you! :)
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Quoting moonlightcowboy:


Good obs! :) Slowing usually indicates a bend starting. He will miss the largest area of the warmest waters of the loop eddy. The high has retreated northeastwards with the 1016mb line far inland now, meaning there will be less resistance. Zeroing in between NOLA and Mobile, most likely over Gulport/Biloxi if it strengthens any. Just won't intensify as much as I'd previously thought. Cat 3 won't happen unless there is a significant stall. But a stall also eventually upwells cooler waters. So any peak intensity won't last long and it'll weaken as it comes ashore.


MLC! Good to see you - saw your post re: surface obs yesterday but the blog was moving too fast to say hi. Best wishes with this thing.
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Quoting TomballTXPride:
At this point it might be time to really start to worry about the rainfall potential. Even if if only makes category 1, there are more indications of a possibility of a stall, and that could create incredible flooding over Lower Alabama into the Panhandle of FL were they already had MORE THAN ENOUGH of their fair share.

true dat
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Quoting HoustonTxGal:


just a suggestion but....Lay it down and try to put it on a side of your house that will be more shielded from direct wind.


thanks. that's what we will do, and cross our fingers
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Quoting TomballTXPride:

We've been waiting for you Cowboy...


Ha! LOL. This has been tough going. Poor ol' models have to be worn slap out - they're gonna need some new wiper blades!!! ;P
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Is this dry air I see intruding from the Southeast and clearing up the North?
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Where are all the people that were bashing me this morning at?
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Quoting 7544:
looks like isaac just jogged ne ?

no, northwest
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Hmmm. from the 5pm FORECAST POSITIONS...

INIT 27/2100Z 26.4N 86.2W 60 KT 70 MPH
12H 28/0600Z 27.4N 87.5W 70 KT 80 MPH
24H 28/1800Z 28.6N 89.0W 80 KT 90 MPH
36H 29/0600Z 29.5N 90.0W 85 KT 100 MPH...NEAR THE COAST
48H 29/1800Z 30.3N 90.7W 75 KT 85 MPH...INLAND
72H 30/1800Z 32.2N 91.8W 35 KT 40 MPH...INLAND
96H 31/1800Z 35.9N 92.1W 25 KT 30 MPH...INLAND
120H 01/1800Z 38.7N 89.3W 20 KT 25 MPH...INLAND


From 24hr to 36hrs: 14 hours - 86.8miles => 6.2mph

From 36hr to 48hrs: 14 hours - 69.4miles => 5.0mph

From 48hr to 72hrs: 24 hours - 146 miles => 6.1mph

From 96hr to 120hrs: 24 hours - 247miles => 10.3mph

Geeze -
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Quoting LargoFl:
..yes its the same here..it rains for a few minutes then stops we get a dry spell and it rains again for a few minutes, most of the winds have died down now too


It is blowing here pretty good, from the south. I think the storm is due west of the Tampa Area now so we are picking up the winds from the bottom of the storm
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I wish the media would stop over hyping this storm. It will be a weak category best. Heavy rainfall will be the issue but this storm does not and will not live up to this ridiculous hype it is getting.
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Quoting interstatelover7165:
Oh, but I thought the data didn't support it?

maybe not now but any tiny increase convection it will be one.
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Quoting Tazmanian:
dran recon went home

any changes
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584. 7544
looks like isaac just jogged ne ?
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Quoting Pirate999:
Interesting.. We are all concerned about NOLA (rightly so) and the flooding but it you look at where landfall is predicted, the bulk of the rain and surge will hit Mississippi and Alabama.


Yep.

If Cantore wanted to impress me, he'd be in Bay St Louis, Pass Christian, Gulfport or Biloxi MS. That's where any slosh will be funneled.
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Quoting truecajun:
does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy


Go ahead and tumble it now just kidding lay it down upside down if you cant pick it up in a shed or something before the wind gets to it
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... looks like Isaac is building here
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Quoting katadman:



Lay it down beforehand and lash the beam to a tree trunk?

idk
anyways, here is isaac's current damage isaac affects
lesser antilles
3 inches of rain reported on martinque
1 indirect death in puerto-rico
minor costal flooding
road closure
widespread power outages in puerto rico
greater antilles
haiti
8 deaths( minimum)
7- year old electro-cuted
5,000 evacuees
3,000 homeless
360 flooded houses
spike in cholera
president cancels trip
14,000 left homes
13,500 in shelters
12 houses destroyed
269 houses damaged
DOMINICAN REPUBLIC
7,800 evacuees
10 rural towns cut off
santo domingo lost electricity
2 men swept away
2 deaths
cuba
elctricity outages
2 houses destroyed
230 in emergency shelters
guests moved out of rooms
intermmmitent rains
gusty winds
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dran recon went home
Member Since: May 21, 2006 Posts: 5091 Comments: 115255
Quoting tennisgirl08:
Isaac seems to be taking a jog North and is slowing considerably.

He is bottom heavy...needs to get the SW side to wrap around. Dry air!


Good obs! :) Slowing usually indicates a bend starting. He will miss the largest area of the warmest waters of the loop eddy. The high has retreated northeastwards with the 1016mb line far inland now, meaning there will be less resistance. Zeroing in between NOLA and Mobile, most likely over Gulport/Biloxi if it strengthens any. Just won't intensify as much as I'd previously thought. Cat 3 won't happen unless there is a significant stall. But a stall also eventually upwells cooler waters. So any peak intensity won't last long and it'll weaken as it comes ashore.
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Quoting truecajun:
does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy
staking it to the ground comes to mind
Member Since: August 16, 2007 Posts: 0 Comments: 397
Quoting MississippiWx:


Still has at least 24 hours. Could still easily reach the forecast from the NHC.

Agree.
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Quoting STXHurricanes2012:

Dont come out saying that...winds are just about there for a hurricane!!!!
Oh, but I thought the data didn't support it?
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Quoting truecajun:
does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy



Lay it down beforehand and lash the beam to a tree trunk?
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Quoting allancalderini:
Would be surprising if Isaac never becomes a hurricane.


I've been away for a couple of hours and he looks a lot worse than before. He almost looks like he was cut in half.
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Quoting Stormchaser121:

Is this even still possible?!?!


No, don't think so. The plains high would have to bridge quickly eastwards to totally block a northerly path out. That window is closing, but I don't think it'd happen in time. That'd be one hulluva coastal stall.
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Quoting interstatelover7165:
Isaac is a fail. I knew he was never gonna be a hurricane.

Dont come out saying that...winds are just about there for a hurricane!!!!
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Quoting gustaveye:
Looks to me that dry air is destroying Isaac. I don't see it getting stronger....just the opposite! NHC says CAT 2 at landfall....i think it will be a weak tropical storm! Is it just me?


I think you are using wishful thinking. But if so, I don't blame you.
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Quoting truecajun:
does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy


I would take mine down -

OR second best, you could at least take the swings inside and then knock it over yourself.

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Quoting samiam1234:


seriously.. the storm is almost landing at the border of Louisiana/Miss.. its almost landing, every can see the north west projection.. and Texans are still thinking its coming for them.. guys come on this will not impact texas in any way...


ahh.. cough cough.. 320 miles is not quite "landing". Agree the direction and landfall but please, had a drink.. scotch or vodka? mm.. speaking of, isn't it martini time?
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Quoting truecajun:
does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy


just a suggestion but....Lay it down and try to put it on a side of your house that will be more shielded from direct wind.
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Quoting mitthbevnuruodo:


Well I agree, I mentioned it earlier and was going to mention it this afternoon but was afraid of getting bashed! But looks like a good swirl of dry was pulled right in to me too


+1

Y'all go ahead and tell it like it is. As long as you can support your observations the folks here will respect that.
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Quoting airmet3:


Aircraft data is not supporting an upgrade.
Isaac is a fail. I knew he was never gonna be a hurricane.
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Howdy, MLC.
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does anyone know the best way to prep a wooden swingset for a storm? i'm so sick of having to fix the swingset after storms. we've repaired it twice. it always gets tumbled over and a beam breaks in the process. any suggestions?? my husband is a city boy, so he's not too handy
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Quoting TropicalAnalystwx13:

He's running out of time.


Still has at least 24 hours. Could still easily reach the forecast from the NHC.
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Well I guess anything is possiable

Link
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Quoting LargoFl:
GFS at 252 hours..oh oh...........
uh Wat is dat?
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Quoting MississippiWx:
Isaac has an excellent outflow pattern and this will help him eliminate dry air issues eventually. You can see that the area east of him has gone from nearly cloudless earlier in the day to being mostly cloudy with bands of rain finally developing there.


He's running out of time.
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Quoting Articuno:

Taz:

7PM CDT= 8PM EDT.


Taz - You can see we are all looking out for you.
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Quoting barbamz:
Very bad feeder band seems to approach Apalachicola Bay.



Probably going to start seeing some surge reports coming in from Apalachicola Bay west by late tonight/tomorrow morning.
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Quoting HoustonTxGal:


I agree, I was just sharing it because it was interesting how it was done.


Yes, it was very interesting how it was done. Thanks for that.
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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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