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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anyone experiencing coastal flooding from storm surge etc?.................COASTAL FLOOD ADVISORY NOW IN EFFECT FOR COASTAL TAYLOR AND
DIXIE COUNTIES THROUGH 8 PM EDT TUESDAY...

.MINOR COASTAL FLOODING IS ANTICIPATED ALONG THE TAYLOR AND DIXIE
COUNTY COAST AS TROPICAL STORM ISAAC MOVES NORTHWESTWARD ACROSS
THE NORTHERN GULF OF MEXICO.

FLZ128-134-281200-
/O.NEW.KTAE.CF.Y.0002.120827T1542Z-120829T0000Z/
COASTAL TAYLOR-COASTAL DIXIE-
1142 AM EDT MON AUG 27 2012

...COASTAL FLOOD ADVISORY IN EFFECT UNTIL 8 PM EDT TUESDAY...

THE NATIONAL WEATHER SERVICE IN TALLAHASSEE HAS ISSUED A COASTAL
FLOOD ADVISORY...WHICH IS IN EFFECT UNTIL 8 PM EDT TUESDAY.

* COASTAL FLOODING...TIDES ARE EXPECTED TO RISE AS MUCH AS 1 TO 2
FEET ABOVE NORMAL. THIS WILL RESULT IN MAXIMUM WATER LEVEL RISES
OF 2 TO 4 FEET ABOVE MEAN SEAN LEVEL AROUND THE TIME OF HIGH
TIDE.

* TIMING...THE ONSET OF HIGH WATER WILL BEGIN AFTER MIDNIGHT
TONIGHT AND MAXIMIZE AROUND THE TIME OF HIGH TIDE AROUND NOON ON
TUESDAY.

* IMPACTS...MINOR COASTAL FLOODING IS ANTICIPATED THAT WILL BE
CAPABLE OF FLOODING LOW LYING COASTAL ACCESS ROADS AND
POTENTIALLY IMPACTING UNPROTECTED STRUCTURES RIGHT ALONG THE
COASTLINE AROUND THE TIME OF HIGHEST TIDE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A COASTAL FLOOD ADVISORY INDICATES THAT COASTAL FLOODING IS
ANTICIPATED BUT IS ONLY EXPECTED TO CAUSE A MINOR IMPACT WITHIN
THE ADVISORY AREA.

&&

$$
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Quoting help4u:
Bob Breck showed 115 mph winds wed morning. That is a major.


that is gusts if it intensifies
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Quoting GetReal:


Eye starting to clear out....
We will test this new "Risk Reduction" system real soon GR.
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if you live in New Orleans, LA do not ride this storm out ues this day light now too get out of town if you do plan on staying your a nut this kiding this is forcast too be a cat 2 storm may be even a cat 3 storm if you do plan on staying i would have a lifejacket some kind of flotation on stan by you may need it if one of the leves fail and water starts poring in so if you have a ch get out of town now
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
Quoting TexNowNM:
Dr. Masters wrote that most in Haiti were killed by collapsed buildings. That means there are many more with terrible injuries. Hope and pray aid can get to them in time to ease their suffering. Makes you grateful for something as simple as Tylenol.


It's really unfortunate that Isaac had to strike Haiti, especially when a lot of Haiti is still living in tents.
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Quoting mitthbevnuruodo:


I keep thinking that as well. All the visible images look like he's wrapping dry in...thought it was just me seeing things as hadn't seen anyone else mention it!


Brian Norcross from TWC just talked about the dry getting pulled into the Isaac.
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Quoting GetReal:


Eye starting to clear out....
And we got people claiming its dry air intrusion... Eh who knows.
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Quoting taco2me61:
Yelp just cooked the last Hamber Meat that was in the Freezer so now I'm done with the Cold Stuff.... Sprinkle here at Cottage Hill Rd and University Blvd :o)
I'm sure a Ton more to go.... Just saying :o)

Taco.... Good to see all The Mobile folks on tonight :o)




I got the bay house ready to go yesterday. It was one of the prettiest days of the summer. Just beautiful. They had a big jubilee around Mullet Point today. For those that don't know, a jubilee is when lack of oxygen in the water in Mobile bay causes fish, shrimp, crabs..ect. to come up to the beach.
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Quoting gbreezegirl:
I'm in gulf breeze and its breezy (yeah go figure) only sprinkles this afgternoon. Waiting and watching.


Same here in fountain, fl north of Panama city.
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Eye starting to clear out.... along with new burst on NW side eye wall.
Member Since: July 4, 2005 Posts: 204 Comments: 8806
Quoting tornadolarkin:
I think a weak cat 3 is very possible, but I'm thinking 105 or 110 mph hurricane at this point. Storm surge will probably be insane though...


Agreed I have it around 105 mph.
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Quoting flcanes:

post again, plz


I guess i don't know what im doing. Couldn't add the picture from my computer. Brand new to blogging.
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Just in from Panama City FL: I threw all the furniture in the pool yesterday. The good news- It looks like Isaac's path is going to my west. The bad news- My wife is not happy, apparently I wasn't supposed to throw in the couch from the living room.
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Quoting luvtogolf:


not me. 105. Dry air is now intruding that will slow down intensification.


I keep thinking that as well. All the visible images look like he's wrapping dry in...thought it was just me seeing things as hadn't seen anyone else mention it!
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But they are closing Destin Commons tonight at 6:00pm & tomorrow!
Quoting greene47:


Okaloosa always the last to issue....ain't scared of nothing I tell ya! lol
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We were expecting 2-3 inches and got 11" so he's a wet one who stretches far out from center. I am on east coast of Fl.
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Quoting flhurricanesurvivor:
fort walton here. No mandatory evacuations but I did hear voluntary for residents south of Hwy 98.
I think just the beaches here. They were going to cut the water to Perdido and Pens Bch tonight but decided not to. They usually mandatory evacuate them when the winds are expected to get up to 40-45 just not safe on the bridges.
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Quoting taco2me61:
Yelp just cooked the last Hamber Meat that was in the Freezer so now I'm done with the Cold Stuff.... Sprinkle here at Cottage Hill Rd and University Blvd :o)
I'm sure a Ton more to go.... Just saying :o)

Taco.... Good to see all The Mobile folks on tonight :o)




Yeah yesterday got all the boards cut for the windows around the house and screwed 2x4's around garage doors. Katrina sucked them in big time. Got a roast,potatoes,carrots and blackeye peas for supper tonight, Gotta have a good dinner before everything goes down hill.

sheri
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Dr. Masters wrote that most in Haiti were killed by collapsed buildings. That means there are many more with terrible injuries. Hope and pray aid can get to them in time to ease their suffering. Makes you grateful for something as simple as Tylenol.
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Quoting mobilebayal:


I am in the Springhill area and it rained a tiny bit about 35 minutes ago.
Yeah, finally something tropical. I'm afraid it's downhill from here. BTW I'm down the hill from St.Iggy off Springhill AV. If it floods, we might change the name to Spring Island.
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Quoting flhurricanesurvivor:
fort walton here. No mandatory evacuations but I did hear voluntary for residents south of Hwy 98.


Okaloosa always the last to issue....ain't scared of nothing I tell ya! lol
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Quoting tatoprweather:
The GFS is bringing the wave that came off Africa as a hurricane over Puerto Rico in about a week??? Is my interpretation ok or what?


It's possible, but it's a week off, so it can't be TOO reliable. Things always change, especially that far out.
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Quoting leelee75k:
Just saw on local news that they are confirming the 14 inches of rain that fell over Sunrise, Tamarac, Lauderhill, Coral Springs area of North Western Broward.

Those wondering if they should or shouldn't prepare because they are outside of the cone, please keep in mind how far we in Broward are from the center of Isaac and what we experienced, you might not get winds, but you might get flooding rains and power outages.
good point made here..issac's flooding rains reach out very far from where he is
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Member Since: July 12, 2007 Posts: 0 Comments: 5995
Quoting auburn:


I missed it..thanks for the update,I am thankful it wasn't more.


Doubtless there will be more as they find them. I'm sure things are a complete mess in the tent cities. They'll probably be finding the dead for days.
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Quoting TreasureCoastFl:
I'm saying strong Cat 2
Agree/low cat three
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Quoting greene47:
Any Okaloosa County residents on tonight? I saw on the weather channel that the surrounding counties (South Walton, Escambia/FL, and Santa Rosa) issued mandatory evac (I'm assuming for coastal areas) Is Okaloosa still a hold out with volunteer?...
fort walton here. No mandatory evacuations but I did hear voluntary for residents south of Hwy 98.
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Storm looks to be wobbling north..
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I think a weak cat 3 is very possible, but I'm thinking 105 or 110 mph hurricane at this point. Storm surge will probably be insane though...

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The GFS is bringing the wave that came off Africa as a hurricane over Puerto Rico in about a week??? Is my interpretation ok or what?
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Quoting TropicalAnalystwx13:
Scratch my comment. Recon is cutting through the western quadrant and heading back towards the center.

I hope they go back to the southern semi circle since they were finding some strong winds there.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Quoting catastropheadjuster:



Over hear in saraland,al nothing but a little wind. been a beautiful day,.

sheri
I'm in gulf breeze and its breezy (yeah go figure) only sprinkles this afgternoon. Waiting and watching.
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Quoting washingtonian115:
Who is still predicting a major hurricane....


not me. 105. Dry air is now intruding that will slow down intensification.
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Quoting washingtonian115:
Who is still predicting a major hurricane....

I'm going between a strong cat1 to moderate cat2, but it could happen.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Quoting asgolfr999:


Grand Bay here....waiting for the power to go out...for a week!!!
maybe 2 weeks if you know what I'm saying :o)

Taco :o)
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Quoting washingtonian115:
Who is still predicting a major hurricane....

It's still possible.
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Bob Breck showed 115 mph winds wed morning. That is a major.
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Quoting asgolfr999:


Grand Bay here....waiting for the power to go out...for a week!!!



Over hear in saraland,al nothing but a little wind. been a beautiful day,.

sheri
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Scratch my comment. Recon is cutting through the western quadrant and heading back towards the center.
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Quoting Tazmanian:



me


I think I might join you Taz. He's entering 31 degree C water now, the center is closing off, moderate sheer, dry air becoming less of an issue, 980 mb now, I'm thinking right at Cat 2/ Cat 3 borderline.
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Quoting StormSurgeon:


Heh heh.....got the panels up on the Island house yesterday and fridge cleaned out....better safe than sorry.
Yelp just cooked the last Hamburger Meat that was in the Freezer so now I'm done with the Cold Stuff.... Sprinkle here at Cottage Hill Rd and University Blvd :o)
I'm sure a Ton more to go.... Just saying :o)

Taco.... Good to see all The Mobile folks on tonight :o)


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Quoting washingtonian115:
Who is still predicting a major hurricane....
I'm saying strong Cat 2
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206. auburn (Mod)
Quoting WeatherNerdPR:

Didn't you read the blog entry ? It's up to 19 now.


I missed it..thanks for the update,I am thankful it wasn't more.
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Taco my daughter just came in from college and said the was someone on tv said they where at mobile bay,ms. she said mom don't they know where there at? I just laughed and told her you had wrote that on the blog,

sheri
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Quoting cat6band:



ALL of them!!


In the Mobile area, we just have that ticker thing at the bottom of the screen.
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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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