Unanswered questions concerning Hurricane Isaac

By: Dr. Jeff Masters , 4:35 PM GMT on August 31, 2012

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The top winds of Tropical Depression Isaac have fallen to 25 mph, but the storm continues to be a potent rain-maker as it heads north-northwest at 11 mph into Missouri. Isaac has spawned up to 20 suspected tornadoes, brought storm surges as high as 13.6' to the coast (in Lake Borgne, LA), and dumped 20" of rain at one station in New Orleans. The 13.27" of rain that fell at Hattiesburg, MS broke the record for wettest August in the city's history (previous record: 13.03" in 1987.) Major flooding is occurring on seven rivers in Louisiana and Mississippi. Isaac is being blamed for at least four deaths in the U.S., 24 in Haiti, and five in the Dominican Republic.

A few notable rainfall totals from Isaac, through 11 am EDT on Friday:

20.08" New Orleans, LA
15.02" Marion, MS
13.99" Pascagoula, MS
13.27" Hattiesburg, MS
10.85" Gulfport, MS
10.39" Slidell, LA
10.17" Biloxi, MS
9.85" Mobile, AL
7.38" Pine Bluff, AR
5.95" Baton Rouge, LA

A major reason for Isaac's heavy rainfall totals has been its very slow motion. This slow speed was due to the fact Isaac has been bumping into a ridge of high pressure that is unusually strong, due to the intense drought over the center of the U.S.; strong drought-amplified high pressure areas are very resistant to allowing any low pressure areas to intrude into their domain. The high pressure area was strong enough this week to allow several all-time records for heat this late in the year to be set:

112° on August 29 at Winner, SD
108° on August 29 at Valentine, NE
107° on August 29 at Corpus Christi, TX
97° on August 29 at Denver, CO (2nd highest so late in the year)


Figure 1. Nighttime view of Hurricane Isaac taken at 1:57 am CDT August 29, 2012, by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi-NPP satellite. The VIIRS day-night band detects light in a range of wavelengths from green to near-infrared, and uses light intensification to enable the detection of dim signals. In this case, the clouds of Isaac were lit by moonlight. Image credit: NASA.

Isaac's beneficial rains falling in drought-stricken regions
Hurricanes get a lot of attention because of the billions in damage they cost, and the lives they disrupt. AIR Worldwide estimated today that insured damage from Isaac would cost up to $2 billion. This does not include damage to infrastructure or uninsured damage, so the final price tag of Isaac's rampage will be more like $3 - $5 billion. However, Isaac is now dumping beneficial rains over Arkansas, Missouri, Illinois, Indiana, Ohio, and Kentucky--regions stricken by the worst drought since the 1950s or 1930s, depending upon the exact location. These regions need 9 - 18 inches of rain to pull them out of drought. Isaac's 3 - 6 inches of rain will not end the drought, but will put a pretty good dent in it. I expect that 3 - 6 inches of rain for a wide swath of prime agricultural land in extreme drought is probably worth at least $5 billion, when you consider that a recent estimate by a Purdue economist put the cost of the great drought of 2012 at more than $77 billion. Only Hurricane Katrina ($146 billion) and the drought of 1988 ($78 billion) have been more expensive disasters, according to NOAA's National Climatic Data Center. Unfortunately, Isaac's arrival is poorly timed, as the storm is arriving during harvest season. The strong winds associated with the storm will flatten many crops, making it more difficult to harvest them, and Isaac's winds may cost farmers several hundred million dollars due to unharvestable crops. Still, the rains from Isaac will be highly beneficial for the success of the upcoming winter wheat season, and for next year's growing season.


Figure 2. Predicted precipitation for the five-day period ending on Tuesday evening shows that Isaac is expected to bring a large region of 3 - 6 inches of rain (red, orange, and brown colors) to Arkansas, Missouri, Illinois, Indiana, Ohio, and Kentucky. Image credit: NOAA/HPC.


Figure 3. The great drought of 2012 has brought so little rain to the Midwest that some areas require over 15" of rain (dark purple colors) to end the drought. Image credit: NOAA/CPC.

Unanswered questions about Hurricane Isaac

1. Did the passage of Hurricane Isaac stir up oil from the Deepwater Horizon oil spill? Isaac was the first hurricane to pass over the site of the 2010 Deepwater Horizon oil spill. We know that large hurricanes are capable of creating currents in deep water at the bottom of the Gulf of Mexico; Hurricane Ivan caused upwelling currents of 0.5 cm/s at a depth of about 500 meters. In an August 28 article in the Huffington Post, Nick Shay, professor of meteorology and physical oceanography at the University of Miami, said: "Winds will push water away from the center of a storm, which causes an upwelling as the ocean tries to adjust. It brings whatever is near the bottom up higher in the water column and currents can then push it towards the coast." Up to 1 million barrels of oil from the spill are estimated to still be present in the deep water sediment, on beaches, and in the marshes of Louisiana, and it is possible some of this oil will wash up on the Gulf Coast in coming months. The storm surge of Isaac also likely flushed out oil lodged in the coastal marshes of Louisiana, but it is unknown how much of a concern this might be.

2. What's the deal with these super-sized Category 1 and 2 hurricanes that have been hitting the U.S.? The past three landfalling hurricanes in the U.S.--Isaac (2012), Irene (2011), and Ike (2008)--have all been exceptionally large, among the top ten on record for horizontal extent of tropical storm-force winds. Each of these storms had an unusually low pressure characteristic of a storm one full Saffir-Simpson category stronger. Is this the new normal for U.S. hurricanes?

3. Did the new $14.5 billion upgrade to the New Orleans levee system cause worse flooding elsewhere? Whenever a new levee or flood control structure is created, you make someone else's flood problem worse, since the water has to go somewhere. Where did the water was stopped by the new $1.1 billion, 1.8 mile-long Lake Borgne flood barrier on the east side of New Orleans go? Did it flow south and contribute to the overtopping of the levees near Braithwaite? Or did it go north and contribute to the 36 hours of storm surge in excess of 5' observed along the Mississippi coast at Waveland? I posed this question to NHC's storm surge expert Jaime Rhome, and he said it was impossible to know without doing detailed storm surge modeling studies.

4. Can only hurricanes beginning with the letter "I" hit the U.S. now? Isaac (2012), Irene (2011), and Ike (2008) are the last three hurricanes to hit the U.S. It turns out that hurricanes that begin with the letter "I" and "C" have more names on the list of retired hurricanes than any other letter (nine each.) I'm thinking Isaac will get its name retired, letting storms beginning with "I" take over sole possession of first place on the retired storms list.

Hurricane Kirk in the Central Atlantic
Hurricane Kirk intensified into a 105 mph Category 2 hurricane this morning, becoming the 2nd strongest hurricane of the 2012 Atlantic hurricane season. Hurricane Gordon was the only stronger storm; Gordon hit sustained winds of 110 mph just before reaching the Azores Islands on August 18. Kirk has probably peaked in intensity, and is about to move over colder waters and gradually decay. Kirk is not a threat to any land areas.


Figure 4. Morning satellite image of Tropical Storm Leslie.

Tropical Storm Leslie a long-range threat to Bermuda, Canada, and the U.S. East Coast
Tropical Storm Leslie formed on Thursday in the Central Atlantic. Leslie's formation date of August 30 puts 2012 in 2nd place for earliest formation date of the season's 12th tropical storm. Only 1995 had an earlier formation date of the season's 12th storm. With records dating back to 1851, this year is only the second time 8 total storms have formed in August. The other year was 2004, when the first storm of the season formed on August 1 (Alex), and the 8th storm (Hermine) formed on August 29th. Satellite loops show that Leslie has a modest amount of heavy thunderstorm activity, and respectable low-level spiral bands and upper-level outflow. Conditions appear ripe to allow Leslie to intensify into a Category 2 hurricane by Sunday. Fortunately, Hurricane Kirk is weakening the ridge of high pressure to the north of Leslie, and Leslie is expected to turn to the northwest and miss the Lesser Antilles Islands. However, steering currents for Leslie are expected to collapse early next week, as Leslie gets stuck between two upper level lows. The storm will then slowly meander over the open ocean for many days, potentially threatening Bermuda. Leslie will stay stuck until a strong trough of low pressure approaches the U.S. East Coast around September 8. This trough should be strong enough to pull Leslie to the north and then northeast by September 9. At that time, Leslie may be close enough to the coast that the storm will make landfall in New England, Canada, or the Mid-Atlantic states. Leslie could also miss land entirely; this all depends upon the timing and strength of the September 8 trough of low pressure. Regardless, Leslie is expected to bring an extended period of high waves to the U.S. coast. According to NOAA's Wavewatch III model, large swells from Leslie will reach Bermuda by Monday, and arrive along the U.S. East Coast on Tuesday. These waves will be capable of creating dangerous rip currents and beach erosion.

Portlight disaster relief charity responds to Isaac
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, are in Mississippi, helping out with Isaac relief efforts. You can check out their progress or donate to Portlight's disaster relief fund at the portlight.org website.

I'm planning on taking Saturday off, but will have a new post for you on Sunday. Have a great holiday weekend, everyone!

Jeff Masters

Hurricane Isaac Louisiana (apphotos)
People play in the storm surge from Hurricane Isaac, on Lakeshore Drive along Lake Pontchartrain, as the storm nears land, in New Orleans, Tuesday, Aug. 28, 2012. (AP Photo/Gerald Herbert)
Hurricane Isaac Louisiana
Portlight volunteers at Biloxi shelter (Portlight)
Portlight volunteers at Biloxi shelter
Hurricane Isaac Louisiana (apphotos)
Research students from the the University of Alabama measure wind speeds as Hurricane Isaac makes landfall, Wednesday, Aug. 29, 2012, in New Orleans, La. Isaac was packing 80 mph winds, making it a Category 1 hurricane. It came ashore early Tuesday near the mouth of the Mississippi River, driving a wall of water nearly 11 feet high inland and soaking a neck of land that stretches into the Gulf. The storm stalled for several hours before resuming a slow trek inland, and forecasters said that was
Hurricane Isaac Louisiana
TS Isaac (Raine911)
Between the rain bands
TS Isaac

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Quoting air360:
Anyone heard from Levi past few days? He hasn't updated his tropical tidbits since Wednesday - curious his thoughts on Leslie


I'm pretty sure his new school year at college just started so he might be slower to update for a while.
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Have I been a bad boy? I seem unable to post anything other than text.
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Quoting taistelutipu:


I remember how it all started, in the episode 'The Corbomite Maneuver' where Bones mutters to himself after Kirk has left sickbay: "What am I, a doctor or a moon shuttle conductor?"

From outer space back to the tropics: Isaac apparently made the Mississippi flow backwards, according to this article.


That's right!!! It was one of the first episodes. I had forgotten that (almost)
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Conditions are lined up perfectly for Leslie to become a powerful hurricane in the open Atlantic. Models will be tough to gauge because of the steering current collapse at days 4 and 5...these scenarios play out highly unpredictably.
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Looks like Leslie might be joining Kirk on his fishing trip?
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Quoting air360:
Anyone heard from Levi past few days? He hasn't updated his tropical tidbits since Wednesday - curious his thoughts on Leslie



he got his own life this like the rest of us he likeyy got in too busy and have not got in the time
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366. mati
Quoting VR46L:


But its a female storm Leslie .... cant see him when he was alive dancing with Kirk Douglas ...

anyways Kirk in rainbow



Lol Leslie Nielson would have danced with a dog let alone Kirk Douglas!!!, a great comedic self depricating person as ever lived.
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Member Since: August 2, 2010 Posts: 22 Comments: 10052
Member Since: August 2, 2010 Posts: 22 Comments: 10052
Quoting psuweathernewbie1:
Leslie is sustaining convection during dmin, good sign for things to come, she really hasn't had an issue with this since she developed into a Depression.


Whatever it is, I think Leslie will be the strongest storm yet this season. I could see it easily going to a Cat 4.
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Quoting Grothar:


The line was used many different ways. At some time or other all our memories fail us. At one time I could recite "War and Peace" now, anything after Chapter 44 is a little fuzzy.


I remember how it all started, in the episode 'The Corbomite Maneuver' where Bones mutters to himself after Kirk has left sickbay: "What am I, a doctor or a moon shuttle conductor?"

From outer space back to the tropics: Isaac apparently made the Mississippi flow backwards, according to this article.
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Member Since: August 2, 2010 Posts: 22 Comments: 10052
2045utc satellite image shows Leslie is exploding
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That big stall Leslie does mid Atlantic, (per recent gfs models) may end up being one of those loop d loop things that Jeanne pulled back in 2004.
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Recurved. There is now an eastward component to H.Kirk.s travels
All times in GMT. Derived from NHC_ATCF data for HurricaneKirk at 31Aug.6pm

The southernmost dot on the connected lines is where TropicalStormKirk became HurricaneKirk
The southernmost dot on the longest line is H.Kirk's most recently reported position.

The longest line is a straightline projection through H.Kirk's 2 most recent positions to its closest approach to the Azores
31Aug.6pm: H.Kirk was heading for passage 749miles(1205kilometres)WNWest of Corvo(CVUdot)

Copy&paste cvu, sma, pxo, lpa, 27.6n50.0w-28.5n50.5w, 28.5n50.5w-29.6n50.7w, 29.6n50.7w-30.6n50.9w, 30.6n50.9w-31.6n50.5w, 30.6n50.9w-44.758n44.087w, 39.725n31.122w-44.758n44.087w into the GreatCircleMapper for a larger map and other information
The previous mapping for comparison
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Member Since: August 2, 2010 Posts: 22 Comments: 10052
Leslie is sustaining convection during dmin, good sign for things to come, she really hasn't had an issue with this since she developed into a Depression.
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Member Since: August 2, 2010 Posts: 22 Comments: 10052
Member Since: August 2, 2010 Posts: 22 Comments: 10052
and Ozzie and Harriett ran for 14 years on television 1952-1966...wow and now...Dancing With The Stars is in it's 14th season...
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Member Since: July 6, 2010 Posts: 113 Comments: 34481
Quoting HurricaneHunterJoe:
Jane Wyatt, was the Ronbo Reagans wife?
No, Jane
Wyman was his wife.
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350. VR46L
Quoting mati:
Nah
Leslie Nielson, a good Canadian:

http://en.wikipedia.org/wiki/Leslie_Nielsen



But its a female storm Leslie .... cant see him when he was alive dancing with Kirk Douglas ...

anyways Kirk in rainbow

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Damn Kirk..you were so close...
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Quoting HurricaneHunterJoe:
And just how long is a nap Gro?


2 hours.
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Quoting HurricaneHunterJoe:
Jane Wyatt, was the Ronbo Reagans wife?


No, that was Jane Wyman was married to Ronald Reagan. Jane Wyatt was on Father knows best.
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Anyone heard from Levi past few days? He hasn't updated his tropical tidbits since Wednesday - curious his thoughts on Leslie
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BULLETIN
TROPICAL STORM ILEANA ADVISORY NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092012
200 PM PDT FRI AUG 31 2012

...ILEANA WEAKENS TO A TROPICAL STORM...


SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.4N 116.1W
ABOUT 395 MI...640 KM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 34481
BULLETIN
TROPICAL STORM LESLIE ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012
500 PM AST FRI AUG 31 2012

...LESLIE COULD BECOME A HURRICANE OVER THE WEEKEND...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...16.7N 51.0W
ABOUT 715 MI...1150 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 34481
BULLETIN
HURRICANE KIRK ADVISORY NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL112012
500 PM AST FRI AUG 31 2012

...KIRK WEAKENS OVER THE OPEN ATLANTIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...32.2N 50.2W
ABOUT 1015 MI...1630 KM S OF CAPE RACE NEWFOUNDLAND
ABOUT 1365 MI...2200 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 34481
Quoting Grothar:


Yes, that was episode 26.
He also said " . . . Dammit Jim, I'm just a country doctor . . . " Man, I have to get life.
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Quoting Grothar:


Spock's Mom, was the Mother on Father Knows Best.

Yes I know. Jane Wyatt or Wyman????????? You know I had just signed off and had to sign on to answer. This is getting crazy. Maybe I'm addicted to this blog!!!! Have a great weekend.
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Jane Wyatt, was that Ronbo Reagans wife?
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And just how long is a nap Gro?
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Quoting kwgirl:
They were all human. Spock's mom was an earthling. So he was mixed races.


Spock's Mom, was the Mother on Father Knows Best.

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Was that a trick question?
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zzzzzzzzzzzzzzzzzzzzzzzzzzz
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335. mati
Nah
Leslie Nielson, a good Canadian:

http://en.wikipedia.org/wiki/Leslie_Nielsen

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I have to go take my nap now.

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We had a Inverted Trof/Easterly Wave show up in San Diego County yesterday and it fired off a bunch of Thunderstorms here in the mountains. Got about 1/2" of rain yesterday.
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Quoting HurricaneHunterJoe:
LOL.....................Hi everybody!
Is this the Star Trek Convention? Was one of Spock's parents human?
They were all human. Spock's mom was an earthling. So he was mixed races.
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Well it looks like everyone has taken off. I will wish you all adieu. I might see ya'll this weekend if I get really bored or can't sleep. Have a good weekend.
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LOL.....................Hi everybody!
Is this the Star Trek Convention? Was one of Spock's parents human?
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Quoting Slamguitar:


This is one of the events I've experienced that really inspired me to be a meteorologist.

Good read


That one took a lot of people by surprise.
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Quoting Grothar:


Wrong spelling, it would have to be Leslie Caron.

True that...
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Quoting DrMickey:

Lesley Ann Warren?


Wrong spelling, it would have to be Leslie Caron.
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Quoting VR46L:


LOL true , can't even think of a famous female Leslie for him to dance with...
Leslie Caron
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Quoting VR46L:


LOL true , can't even think of a famous female Leslie for him to dance with...

Lesley Ann Warren?
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Quoting kwgirl:
Ad nauseum. Dang now I can't remember the correct spelling.


It's OK, don't get yourself sick over it.
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323. VR46L
Quoting TomballTXPride:

Prolly wishes he could do the fuji dance with Leslie though. That's oughta perk him up....


LOL true , but I can't even think of a famous female Leslie for him to dance with...
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Quoting Slamguitar:


Michigan, Huron, or Erie would be the best bets. They were warmer a little while ago.

8/3:


Latest:

It could happen and it would be interesting up here.
Member Since: March 16, 2012 Posts: 127 Comments: 7984

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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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