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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2604. tkeith
I see the NHC has backed off the Cat 2 forecast. That's good.

Welcome home Pat...I guess :)
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To anyone: How might SST be playing in the weirdness of Isaac?

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Quoting CCkid00:

Hi neighbor! I'm in Denham Springs (Juban Road).


WASUUUUP!!!!??? lol. Hwy 16 in Watson here.
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2601. LargoFl
gee just went outside..the moisture laden clouds are racing northward here on the gulf coast of florida, must be a feeder band here..lots of rain coming up folks.......and in polk county florida there is a BOIL WATER notice,seems their water treatment plant went down yesterday....
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2600. dipchip
NHC: "Center fixes from the aircraft indicate that the storm has wobbled on a generally westward course over the past few hours. This is believed to be temporary …however and the longer-term motion estimate is about 305/10."

Isaac has been wobbling west now for 18 hours. Since leaving the Dry Tortugas; Isaac has been making good a course of 285 and I suspect this will continue and make land fall near Cameron La. Expect the Eye to close by 8 AM EDT.
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2599. Patrap
06z Early Cycle NHC model tracks
Isaac

Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)




Early Model Wind Forecasts

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Quoting Caner:


I'm curious:

Why didn't the fun times end in East Pakistan in 1970 when a minimal cat 1 drowned half a million people?

Do only American deaths count in ending "fun times"?



no they dont have the money to alter storms like we do...but im sure eventually we will do it for them just like we take care of the entire earth and still catch slack about doing so! ungreatful other countries are!
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Quoting Fl30258713:


(...) History has given us 911 recording of people calling for help in the middle of a hurricane because they didn't heed the warnings. Some of us see that as a pity and want to help but can't in the middle of a storm, others of us see that as a form of stupidity & natural selection.


And some are going out and save them but loose their lives instead.
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Quoting CaneHunter031472:
Don't worry guys. Y'all keep shootin from the hip, there's plenty of crow for all to eat :-)





kill it with the off topic photos plzs
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Quoting xtremeweathertracker:
06Z Models are taking Isaac farther west.






Those I do NOT like. Everyone have a great Tuesday!
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I wouldn"t be surprised if it was seeded, It certainly seems this storm struggled to gain strength when conditions were certainly favorable. When you mess with mother nature she usually wins.
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Uh oh Isaac is waking up this morning... Just opened his eye lol.
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2591. Patrap
Please keep the er, GLP chatter there.

It's a useless use of Blog space here.

Thanx.

; )
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2589. CCkid00
Quoting HimacaneBrees:
Nice here in Denham Springs La. this morning. Enjoying the breeze and a cup of coffee. 24 hours from now, likely a different story.

Hi neighbor! I'm in Denham Springs (Juban Road).
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06Z Models are taking Isaac farther west.




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2587. Patrap


Moon Halo

The familiar 22° halo around the Sun or Moon occurs because of refraction in tiny hexagonal ice crystals in the air. With the 60° apex angle of the prism formed by extending the sides of the crystal and the index of refraction of ice (n=1.31) one can calculate the angle of minium deviation to be 21.84°.
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Quoting CCkid00:

don't know what seeding is but there was a big bright halo around the moon last night here where i live (about 45 miles NW of NOLA).


our govt for sure alters these storms, its cheaper to do that than let a cat 5 hurricane hit the U.S....they say they dont but when have they ever told the truth
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2585. Caner
Quoting Maineweatherguy20023:

Yes the "fun times" when NOLA was flooded and thousands of people died in 1 catastrophic storm after another. Wernt those times so fun and lovely?? :(


I'm curious:

Why didn't the fun times end in East Pakistan in 1970 when a minimal cat 1 drowned half a million people?

Do only American deaths count in ending "fun times"?

Member Since: June 27, 2011 Posts: 0 Comments: 179
Well, school and my kids are calling. Made note to find kindle cord so I can recharge it, to take down top of gazebo, and to put lawn furniture up just in case. Better safe than sorry. On a good note town has reserved hotel rooms for people to come in to restore our electric though they couldn't find a generator to keep the water running anywhere. *G*
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2583. Patrap
Time off and rest is always a good thing.

Ill be on for another Hour or so, then we have to get a few things done outside and check on some neighbors as well.
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2582. GetReal
Member Since: July 4, 2005 Posts: 204 Comments: 8806
2581. CCkid00
Quoting GulfCoastPirate:



You think this storm was seeded?


don't know what seeding is but there was a big bright halo around the moon last night here where i live (about 45 miles NW of NOLA).
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Morning Patrap! Hope you had a great vacation! good to have you back here.
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2579. air360
Quoting MAweatherboy1:
6z GFS has come more in line with the Euro solution on our potential future storm, recurving it well before it gets to the US... If this verified Bermuda would be hit pretty hard though.



But just remember - at this far out anything is possible. One of the runs yesterday showed that same storm you are talking about following the same path as Isaac. So it is kind of all over the place right now.
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Got my first rain from this went bye fast all the little green frogs around my house is givibg my dog fits this morning.

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Quoting sar2401:


Better get used to it. These ghastly storms are being caused by global warming...or cooling...or cloud seeding...or HAARP. This is the new normal. Regular, normally sane people, up at 0830 UTC watching really crummy looking storms do nothing for days and weeks on end. The fun times ended in 2005. :)

Yes the "fun times" when NOLA was flooded and thousands of people died in 1 catastrophic storm after another. Wernt those times so fun and lovely?? :(
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Good morning yawn....stretch. Welcome back patrap . from Slidell evacuated to Covington. running on 4 hours sleep and beat down from moving patio furniture and packing for this adventure......still waiting to see what Isaac is going to do.
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Quoting hurricaneoz:
Not to downplay the wind and the storm surge too much, it seems that Isaac is destined to be more of a rainfall / flood event. If it manages to track close to the mississippi for 24 hrs+ and drops 10-15 inches of rain, how will this compare with the 2011 floods?


One positive thing is, the river is extremely low right now.
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Patrap...you made it back? Glad to see you posting!
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Link On the Long Floater you have to check warn for trop points and county for lats and lons.
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2571. Caner
Member Since: June 27, 2011 Posts: 0 Comments: 179
2570. o22sail
Quoting Masquer08er:
Patrap, Glad to see you're still here at WU. I was on here as SaymoBEEL 2003-2008 and enjoyed your posts so much.
...and we were doing exactly this almost 7yrs ago to the minute. LOL.
:)
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2569. LargoFl
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looked like Isaac moved a little W or sould i say overe night
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2567. Patrap
Additional Links
• View all metro area closures
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now that that the intensity was so far off they are going to hype up the flooding so that they have a reason to actually have such big media coverage! NEXT!
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Nice here in Denham Springs La. this morning. Enjoying the breeze and a cup of coffee. 24 hours from now, likely a different story.
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2564. HCW
Quoting ugajag:
Not a bad morning here in Mobile..Winds about 15mph..My concern here is rain..We have had so much since June and are expecting 10-15" with Isaac.. Also the ground is so moist that 40-50 mph winds will bring down trees


Those rainfall totals are very unlikely unless the NE side of the storms fills in. Greetings from Dauphin Island . The highest expected winds for Mobile are 44 mph based off the 4am advisory
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2563. Patrap
Isaac RGB Loop

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2562. Melagoo
Quoting MAweatherboy1:
6z GFS has come more in line with the Euro solution on our potential future storm, recurving it well before it gets to the US... If this verified Bermuda would be hit pretty hard though.


Bermuda rarely ever takes a direct hit
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2561. LargoFl
The National Weather Service in Tampa FL has issued a

* Flood Warning for
the Alafia River at Lithia
* from this evening until Thursday afternoon
* at 08pm Monday the stage was... 12.7 feet
* minor flooding is forecast
* flood stage is 13 feet
* forecast to rise above flood stage by tonight and continue to rise to near
13.6 feet by tomorrow early afternoon. The river is expected to fall below flood stage
by Thursday morning.
* Impact... at 13 feet... River Drive and Squirrel Run way downstream of State
Road 640 are completely covered by water. One home begins to flood
* impact... at 12 feet... water begins to affect River Drive and Squirrel Run
way downstream of State Road 640
* flood history... this crest compares to a previous crest of 13.6 feet on Aug 9
1957.
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What imagery should I be looking on for this eye, or is everyone still "eyecasting" from last night? ;-)
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Quoting unc70:


My original question came from looking at Isaac trying to cut off dry air near west coast of Florida. If that outer band stretching almost to Texas doesn't tighten a lot, it looks almost capable of smacking almost the entire coast from about Tampa to Alabama.

I know that is unlikely, but that band is big trouble for wherever it rotates ashore.




Not sure whether it is related to outer bands, but we have been getting really heavy rain and thunder storms all night here on Grand Cayman
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2558. MahFL
Quoting RTSplayer:
According to my math, storm is actually only about 15 to 16 hours from closest approach to NOLA.

With that track forecast, NHC must be expecting it to slow down by another 3 or 4 miles per hour within then next 2 advisories to make up for it's current speed...


The NHC deputy director said it would be at 6 mph or so at the shore, a terrible speed for a hurricane to pass by.
Member Since: June 9, 2004 Posts: 0 Comments: 3388
Convection is already obscuring the eye, looks like its trying to wrap around the north side a little.

Member Since: February 11, 2012 Posts: 82 Comments: 7643
2555. LargoFl
Quoting RTSplayer:
I might be getting a mist/sprinkle from that tiny band. Hold up let me go check.
..just got a good rain here for a few minutes by me, guess this will be what its going to be like the next few days..sun then rain,sun then rain and a wind gusts
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Not to downplay the wind and the storm surge too much, it seems that Isaac is destined to be more of a rainfall / flood event. If it manages to track close to the mississippi for 24 hrs+ and drops 10-15 inches of rain, how will this compare with the 2011 floods?
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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.