Little change to Isaac, but storm poses a serious storm surge threat

By: Dr. Jeff Masters , 3:25 PM GMT on August 27, 2012

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Tropical Storm Isaac has changed little in strength or organization this morning, as the storm heads northwest at 14 mph towards the Central Gulf Coast. There are two hurricane hunter aircraft in the storm, and Isaac's central pressure held steady at 989 mb at the 8:30 am and 9:15 am center fixes. Top surface winds remain near 65 mph. Infrared and visible satellite loops show that Isaac is a very large storm, but isn't very symmetric. Heavy thunderstorm activity is lacking on the southeast side, where 10 knots of wind shear is driving dry air into the circulation. The center is surrounded by a ring of echoes now, which was not the case on Sunday. However, the echoes are weak. The 8:30 am center report from the Hurricane Hunters reported about half of a ragged eyewall, but the 9:15 am report did not mention any evidence of an eyewall. Isaac will have to form an eyewall in order to intensify significantly.


Figure 1. Morning satellite image of Isaac. Note the lack of heavy thunderstorm activity on the storm's southeast side, where dry air and wind shear are combining to interfere with development.

Isaac's rains
Isaac's heaviest rains have fallen along a swath from the east coast of Florida near West Palm Beach to the center of the state, just south of Orlando. West Palm Beach received 7.57" of rain from Isaac as of 10 am EDT this morning. A trained spotter in Western Boynton Beach reported 10" of rain from midnight to midnight Sunday. Heavy rains from Isaac are lingering over Cuba but have ended in Haiti and the Dominican Republic; flash floods in Haiti from Isaac's torrential rains killed at least nineteen, and two died in the Dominican Republic.


Figure 2. Radar-estimated rainfall from Melbourne, Florida radar shows that Isaac has dumped a wide swath of 3+ inches of rain (orange colors) across the state.

Latest model runs for Isaac
The latest set of 0Z and 06Z (8 pm and 2 am EDT) model runs are fairly unified taking Isaac ashore near Southeast Louisiana late Tuesday night or early Wednesday morning, but continue to show major differences in what happens after that. It is still uncertain if a trough of low pressure passing to the north of Isaac will be able to turn the storm due north, as the ECMWF model is predicting, or bypass the storm, allowing a more west-northwest motion into western Louisiana, like the GFS model is predicting. In either case, Isaac is likely to slow down as it approaches the coast, which will increase the damage potential fro m its wind, storm surge, and rains. The latest 8-day precipitation forecast from the GFS model calls for 10 - 20 inches of rain over much of Louisiana. The ECMWF model predicts that these heavy rains will fall more over Mississippi. It appears likely that Arkansas will see some heavy rains from Isaac late in the week, which would help put a dent in the exceptional drought conditions there.


Figure 3. Predicted precipitation for the 8-day period from 2 am Monday August 27 to 2 am Tuesday September 4, from the 2 am EDT August 27 run of the GFS model. This model is predicting a wide swath of 5 - 10 inches of rain (orange colors) will affect portions of Louisiana. Additional very heavy rains are predicted for the Midwest, as moisture from Isaac interacts with a cold front. Image credit: NOAA/NCEP.

Intensity forecast for Isaac
Isaac is currently crossing over a relatively cool eddy of water, which will keep intensification slow today. By tonight, the total heat content of the waters increases, which should aid intensification. Low wind shear of 10 knots or less is likely until landfall. An analysis of upper level winds from the University of Wisconsin CIMSS shows that upper-level outflow to the north is not as strong as yesterday, which should also slow intensification today. The models forecast the upper-level outflow should improve by Tuesday. A storm this large will have trouble undergoing rapid intensification, and Isaac's most likely intensity at landfall will be as a Category 1 hurricane, which is what most of the intensity models are forecasting.


Figure 4. Track of Hurricane Gustav of 2008, which followed a path very similar to that of Isaac's predicted path.

Storm surge forecast for Isaac
Storm surge is the primary damage threat from Isaac. Isaac is a huge storm, with tropical storm-force winds that extend out 205 miles from the center. For comparison, Hurricane Katrina at landfall had tropical storm-force winds that extended out 230 miles from its center. Isaac's large size will enable it to set a large area of the ocean into motion, which will generate a large storm surge once the storm approaches land on the Gulf Coast. Water levels at Shell Beach, Louisiana, just east of New Orleans, were already elevated by 1' this morning. Conversely, water levels have fallen by 2' this morning at St. Petersburg, Florida, where strong offshore winds due to Isaac's counter-clockwise circulation have carried water away from the coast. The latest 6:30 am EDT Integrated Kinetic Energy analysis from NOAA's Hurricane Research Division put the destructive potential of Isaac's winds near 0.6 on a scale of 0 to 6, but the destructive potential of Isaacs's storm surge was 2.1 on a scale of 0 to 6. I expect this destructive potential will rise above 3 by time Isaac makes landfall, making Isaac's storm surge similar to that generated by Category 2 Hurricane Gustav of 2008, which followed a path very similar to Isaac's predicted path. Gustav brought a storm surge characteristic of a Category 1 hurricane to New Orleans: 9.5' to Lake Borgne on the east side of the city. A higher Category 2-scale surge occurred along the south-central coast of Louisiana, and was 12.5' high in Black Bay, forty miles southeast of New Orleans. Recent model runs indicate Isaac may slow down to a forward speed under 5 mph on Tuesday evening and Wednesday morning, close to the coast. If Isaac is just offshore at this time, the coasts of Southeast Louisiana, Mississippi, Alabama, and the Florida Panhandle will be exposed to a large storm surge with battering waves for two high tide cycles. This sort of extending pounding will be capable of delivering more damage than the storm surge of Hurricane Gustav of 2008.

The affect of storm size and angle of approach on storm surge
A 2008 paper by Irish et al., The influence of storm size on hurricane surge, found that large storms like Isaac are capable to delivering a 30% larger storm surge to the coast than a smaller storm with the same maximum wind speeds. The angle with which the storm hit the coast is important, too--a storm moving due north or slightly east of north will deliver a storm surge about 10% greater than a storm moving NNW or NW. Consult our Storm Surge pages for detailed information on what the risk is for the coast. I expect that Isaac's storm surge will be about 30% higher than the typical surge one would expect based on the maximum wind speeds.

Isaac's storm surge will provide the first test of the newly-completed New Orleans levee system upgrade. In the wake of the disastrous storm surge flooding from Hurricane Katrina in 2005, Congress appropriated $14.5 billion to upgrade the New Orleans levee system to withstand a Category 3 hurricane storm surge. Katrina was a Category 3 storm at landfall, but the storm passed far enough to the east of the city that its storm surge was characteristic of a Category 1 - 2 storm at the places where the city's flood walls and levees failed. The new flood defenses were only partially completed in time for the arrival of Hurricane Gustav in 2008, which hit Central Louisiana as a Category 2 storm. Gustav brought a storm surge characteristic of a Category 1 hurricane to New Orleans: 9.5' to Lake Borgne on the east side of the city. Since that time, the imposing 2-mile long IHNC Flood Barrier has been completed to block off the funnel-shaped pair of canals on the east side of the city. I expect New Orleans' new flood defenses will be able to hold back Isaac's surge, but areas outside the levees are at risk of heavy storm surge damage.


Figure 5. A portion of New Orleans' new $14.5 billion dollar flood defenses, as taken from an Army Corps of Engineers map.

New Orleans flood defense info
Army Corps of Engineers map of the new flood defenses
Army Corps of Engineers video showing the flood defenses
New York Times article, Vast Defenses Now Shielding New Orleans

Invest 97L off the coast of Africa
A tropical wave (Invest 97L) is located in the Middle Atlantic, about 1050 miles west-northwest of the Cape Verde Islands. The storm has a modest amount of spin and heavy thunderstorms, and is under moderate wind shear. In their 8 am EDT Tropical Weather Outlook, NHC gave 97L a 30% chance of developing by Wednesday morning. None of the reliable models foresee that 97L will be a threat to the Lesser Antilles Islands, and high wind shear should begin to tear the disturbance apart on Tuesday.

Another tropical wave that moved off the coast of Africa on Sunday is located just south of the Cape Verde Islands. This disturbance is moving west at 10 - 15 mph, and could arrive in the Lesser Antilles around September 2. Several models develop the disturbance into a tropical depression late this week, and NHC is giving the disturbance a 10% chance of becoming a tropical depression by Wednesday morning.

Angela Fritz will have a new post here by 6 pm EDT. I'm in Atlanta to help out The Weather Channel with their on-air hurricane coverage, and will doing a few 3-minute tropical updates at 30 minutes past the hour between 2:30 - 7:30 pm EDT today.

Jeff Masters

Tropical Storm Isaac (chelina)
View from the north side of the Sunshine Skyway Bridge.
Tropical Storm Isaac
our street at noon today (seflagamma)
Aug 26, 2012: Isaac floods our street really bad. Now nearly 11
our street at noon today

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winds are starting to pick up by my house right now.......
Member Since: August 6, 2011 Posts: 4 Comments: 38474
Flew over me around 12:37PM CDT, nearing storm by now shortly.
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Quoting Neapolitan:
97L is doing a slow fade; winds are now down to 25 knots, while the pressure is a pretty high 1011:

AL, 97, 2012082718, , BEST, 0, 206N, 415W, 25, 1011, DB, 34, NEQ, 0, 0, 0, 0, 1013, 180, 100, 0, 0, L, 0, , 0, 0, INVEST, S,


just like Gordon...any model runs...Azores again?
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by the looks of it this is the start of our (PRE)98L

...TROPICAL WAVES...
TWD
A 1012 MB LOW IS CENTERED SE OF THE CAPE VERDE ISLANDS NEAR
11N20W
. A TROPICAL WAVE EXTENDS N FROM THE LOW TO 21N17W. THE
SYSTEM IS MOVING W AT 15 KT. SCATTERED MODERATE CONVECTION IS
NEAR THE LOW CENTER FROM 9N-14N BETWEEN 18W-26W. SCATTERED
SHOWERS ARE ELSEWHERE WITHIN 60 NM OF THE WAVE AXIS.

TWO
A TROPICAL WAVE LOCATED NEAR THE CAPE VERDE ISLANDS IS PRODUCING
DISORGANIZED SHOWERS AND THUNDERSTORMS. ENVIRONMENTAL CONDITIONS
ARE CONDUCIVE FOR SOME GRADUAL DEVELOPMENT OF THIS WAVE DURING THE
NEXT COUPLE OF DAYS. THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES WESTWARD AT 10 TO 15 MPH
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Isaac is a lot like Ike and Irene a big storm with low pressure, but the winds not translating to the surface.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting RitaEvac:


Was home for lunch and I swear I saw a hurricane hunter plane going over me coming down I-45 from Ellington Airport, it was loud which caught my attention and then headed towards gulf gaining altitude. Looked like a bomber plane

Probably was an HH. I'm not sure if they are flying the C-130s or the P-3s out of Ellington, tho. For an HH, it would have straight wings (perpendicular to the body). 4 engines for both.
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The training continues, though the feeder band responsible for today's PBC deluge appears to be finally moving offshore--and the long arrow south-southeast Miami looks as though it will stay offshore, as well:

rain
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Quoting trHUrrIXC5MMX:
From the current recon...
why did they flew around there for???



They had trouble getting clearance to descend.
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Quoting trHUrrIXC5MMX:


Time: 17:37:30Z
Coordinates: 26.6667N 86.4667W
Acft. Static Air Press: 842.9 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,456 meters (~ 4,777 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 43° at 51 knots (From the NE at ~ 58.6 mph)
Air Temp: 15.4°C* (~ 59.7°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 53 knots (~ 60.9 mph)
SFMR Peak (10s) Sfc. Wind: 61 knots (~ 70.1 mph)
SFMR Rain Rate: 42 mm/hr (~ 1.65 in/hr)

61kt is 70 mph...
which goes with this data BUT it's rain contaminated
That's weird because none of the raw data has high rain rates:


180130 2543N 08539W 8410 01443 //// +164 //// 241058 060 060 007 01
180200 2542N 08538W 8408 01450 //// +181 //// 239060 063 061 007 01
180230 2541N 08537W 8408 01455 //// +183 //// 243054 058 058 006 01
180300 2540N 08535W 8413 01453 //// +185 //// 244051 051 055 006 01
180330 2538N 08534W 8409 01461 //// +189 //// 243053 054 055 005 01
180400 2537N 08532W 8410 01464 //// +197 //// 241052 054 055 005 01
180430 2536N 08531W 8409 01466 //// +187 //// 242048 051 050 003 01
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Charmeck:

if you look at the info on the flags - the plane dropped from around 18,000 ft to 5,000 ft. The circling was to come down.


couldn't they descend as they were going into the storm...instead of spiraling down
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Quoting Dsntslp:
Well, the drain is not clogged. It is just too much water coming in too fast at once down the street and down the small canal at the same time and it is too much for the drain so it is taking the path of least resistance over the top of the drain. Nothing can be done so I am off to go try and figure out how I can...ohhhhhhh!!! I can open the pump valve on the pool! It will purge water from the pool into the already overflowing canal behind my house but it will allow the water in my home to go back in the pool! BBL!! :)


Good luck and don't get hurt or electrocuted in the process...
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Both the 12z GFDL and HWRF predict a Cat2/3 storm. How can our "hurricane only models" be so far off?
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Quoting CajunCrawfishhunter:
1:00 PM CDT Mon Aug 27
Location: 26.1°N 85.9°W
Moving: NW at 14 mph
Min pressure: 984 mb
Max sustained: 65 mph


wouldnt this be due west in 3 hours

Agree something is fishy.It looks due west on SAT and the track confirms it. IDK thats not good.
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Quoting MiamiHurricanes09:
61kt SFMR reading?

180200 2542N 08538W 8408 01450 //// 181 //// 239060 063 061 007 01


Unflagged and low-ish rain rate. If there really has been a 5 mb pressure drop then I'd expect the winds to increase at some point, and with the data indicating maximum winds a little closer to the center then I don't have a reason to doubt it.
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593. CJ5
Quoting RitaEvac:


Was home for lunch and I swear I saw a hurricane hunter plane going over me coming down I-45 from Ellington Airport, it was loud which caught my attention and then headed towards gulf gaining altitude. Looked like a bomber plane


Cloud Seeding operation, I bet. j/k
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Quoting tennisgirl08:


Is this the latest run? What are your thoughts on the Euro?


Well I'm happy to see the Euro made a shift west. Other than that, I still don't think it has it quite right. but thats just IMO
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Quoting Thing342:
Recon found This:

Time: 18:02:00Z
Coordinates: 25.7N 85.6333W
Acft. Static Air Press: 840.8 mb (~ 24.83 inHg)
Acft. Geopotential Hgt: 1,450 meters (~ 4,757 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 239° at 60 knots (From the WSW at ~ 69.0 mph)
Air Temp: 18.1°C* (~ 64.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 63 knots (~ 72.4 mph)
SFMR Peak (10s) Sfc. Wind: 61 knots (~ 70.1 mph)
SFMR Rain Rate: 7 mm/hr (~ 0.28 in/hr)
(*) Denotes suspect data


rain contaminated...
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Thanks everyone for the replies regarding the HH spiral flight pattern. :-)
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Quoting trHUrrIXC5MMX:
From the current recon...
why did they flew around there for???


if you look at the info on the flags - the plane dropped from around 18,000 ft to 5,000 ft. The circling was to come down.
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Quoting MiamiHurricanes09:
61kt SFMR reading?


180200 2542N 08538W 8408 01450 //// +181 //// 239060 063 061 007 01


Time: 17:37:30Z
Coordinates: 26.6667N 86.4667W
Acft. Static Air Press: 842.9 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,456 meters (~ 4,777 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 43° at 51 knots (From the NE at ~ 58.6 mph)
Air Temp: 15.4°C* (~ 59.7°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 53 knots (~ 60.9 mph)
SFMR Peak (10s) Sfc. Wind: 61 knots (~ 70.1 mph)
SFMR Rain Rate: 42 mm/hr (~ 1.65 in/hr)

61kt is 70 mph...
which goes with this data BUT it's rain contaminated
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Flight level winds of 63kts being reported on the south side of the center. Overall, the core seems much better than when the last hunters were in the storm.
Member Since: July 15, 2006 Posts: 17 Comments: 10247
Quoting trHUrrIXC5MMX:
From the current recon...
why did they flew around there for???



There is another blow up of convection there. Hmmm
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.........................The bad weather and tornado's are spreading westward now, our turn on the gulf coast is fast approaching...stay safe out there
Member Since: August 6, 2011 Posts: 4 Comments: 38474
Recon found This:

Time: 18:02:00Z
Coordinates: 25.7N 85.6333W
Acft. Static Air Press: 840.8 mb (~ 24.83 inHg)
Acft. Geopotential Hgt: 1,450 meters (~ 4,757 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 239° at 60 knots (From the WSW at ~ 69.0 mph)
Air Temp: 18.1°C* (~ 64.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 63 knots (~ 72.4 mph)
SFMR Peak (10s) Sfc. Wind: 61 knots (~ 70.1 mph)
SFMR Rain Rate: 7 mm/hr (~ 0.28 in/hr)
(*) Denotes suspect data
Member Since: August 1, 2012 Posts: 0 Comments: 436
Quoting dogsgomoo:
http://www.examiner.com/article/louisiana-activat es-4000-national-guardsmen-securing-sinkhole-equip mentThey are not taking Isaac lightly but there's really only so much they can do. If it blows during the storm and all that stuff gets dispersed. I'm not even sure, what is under it in the cavern? Butane? By products from the refining process?


I read that it was butane and will be huge if it does blow. They even evacuated days ago, just in case. Knowing what rain does to sinkholes this doesn't sound good. Take a look in this video. AboveTopSecret did a big article on it yesterday.

Video of Sinkhole
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Does the "cumulative wind history" graphic depicted on the National Hurricane Center website strike anybody else as a bit generous? http://www.nhc.noaa.gov/refresh/graphics_at4+shtml /163340.shtml?swath#contents The currently posted map of Isaac's winds indicated that tropical storm force winds extended up to Brooksville, FL on the West Coast and Palm Beach on the East Coast. Besides the FL Keys and offshore buoys, I would be interested to see a single report of sustained tropical storm force winds on the FL mainland from TS Isaac. I have noticed this many times before actually.

Perhaps instead, this map counts gusts to tropical storm force (yellow) and hurricane force (red) respectively?
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Quoting CajunCrawfishhunter:


Good luck Hanna

you too Cajun :)
Member Since: September 5, 2007 Posts: 0 Comments: 3487
Yep!! I did see em

HOUSTON (KTRK) -- The military is bracing for Tropical Storm Isaac no matter where it might hit. Planes and personnel from across the Gulf Coast are being relocated, including the Hurricane Hunters to Ellington Field.

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The planes are C-130 J model aircraft, flown in from Mississippi. One plane will take off and head into the hurricane zone Monday night at approximately 6pm.

A crew of eight to 10 hurricane hunters took off in the same type of plane late this morning. Normally, these planes are housed at Keesler Air Force base in Biloxi, Mississippi. But because they're near the target of where Isaac will make landfall, they made the decision to fly in and out from Ellington.

The planes are basically flying weather stations collecting and transmitting data to the National Weather Center via satellite every 90 seconds, so they have a real-time reading of how the storm strengthens or weakens as it moves.

We spoke with one pilot who's been flying in and out of Isaac for the last six days.

"When it's disorganized like that, it's harder to fly in the center, so it has been more of a challenging mission as opposed to a very strong storm where it's obvious where the eye is" said Lt. Col. Ty Piercefield.

Crews fly for about 10 hours at a time. Right now, there is a rotation of three crews, so Hurricane Hunters will be monitoring this storm 24/7.
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First bands appearing...
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97L is doing a slow fade; winds are now down to 25 knots, while the pressure is a pretty high 1011:

AL, 97, 2012082718, , BEST, 0, 206N, 415W, 25, 1011, DB, 34, NEQ, 0, 0, 0, 0, 1013, 180, 100, 0, 0, L, 0, , 0, 0, INVEST, S,
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Quoting CybrTeddy:
984mb.. and it's not a hurricane yet. It's continuing to expand its wind field, and that means surge is going up.


Even without anything more than minimal Category 1 wind speeds, Isaac is going to do a heck of a lot of damage to coastal areas with storm surge, and cause extensive flooding problems both around the coast and far inland.
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Quoting Felix2007:

Told you! Pressure down to 984mb though, but when will the winds respond to that??


According to my local met, the HH found surface winds @ 80? Is this not true?
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Quoting CJ5:
Well, it looks like Kirk will give the DNC Convention equal weather representation.


WAY TOO FAR OUT. We still don't even know where Isaac is going 2 days out, not a chance we know where Kirk's going in 10+ days, oh and it hasn't even developed yet. At first they were saying Isaac would ride up the east coast too.
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Quoting cynvision:

I'd love one of the learned bloggers to explain the strip of rain on the east side of Florida. ?


Yes, please someone give us an explaination (in layman's terms) about why there seems to be a separate storm trying to set itself up on the east coast
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From the current recon...
why did they flew around there for???

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61kt SFMR reading?

180200 2542N 08538W 8408 01450 //// 181 //// 239060 063 061 007 01
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Methurricanes:
984mb Tropical storm, whats the record for the lowest pressure for a Tropical storm?


I have been following Atl tropical wx for 40 years, and have NEVER seen a 984MB TS in the months of August and Sept.... Late in the season there have been some instances.
Member Since: July 4, 2005 Posts: 204 Comments: 8874
Member Since: August 6, 2011 Posts: 4 Comments: 38474
Quoting Jwd41190:


I don't know but I am curious myself....



Category One Hurricane

Maximum Sustained Wind Speed: 74-95 miles per hour
Damage Category: Minimal
Approximate Pressure: Above 980 Mb
Approximate Storm Surge: 3-5 feet


Category Two Hurricane

Maximum Sustained Wind Speed: 96-110 miles per hour
Damage Category: Moderate
Approximate Pressure: 979-965 Mb
Approximate Storm Surge: 6-8 feet


Category Three Hurricane

Maximum Sustained Wind Speed: 111-129 miles per hour
Damage Category: Extensive
Approximate Pressure: 964-945 Mb
Approximate Storm Surge: 9-12 feet


Category Four Hurricane

Maximum Sustained Wind Speed: 130-156 miles per hour
Damage Category: Extreme
Approximate Pressure: 944-920 Mb
Approximate Storm Surge: 13-18 feet


Category Five Hurricane

Maximum Sustained Wind Speed: 157 miles per hour and higher
Damage Category: Catastrophic
Approximate Pressure: Below 920 Mb
Approximate Storm Surge: More than 18 feet
Member Since: September 18, 2007 Posts: 0 Comments: 1074
Interesting to note on the graphic for Gustav's track on Dr. Masters blog (above), that Gustav intensified from a tropical storm to a cat 4 in roughly the same distance as Isaac has to travel across the GOM.

Not gonna happen, but interesting, nonetheless.
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984mb.. and it's not a hurricane yet. It's continuing to expand its wind field, and that means surge is going up.
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Quoting pottery:

Yeah, I wondered that too.


I think it was irene last year, 70 mph tropical storm : pressure around 950 mb
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Quoting Grothar:
Gro, looking at that picture, I believe it looks like the collision of frontal boundaries. But going in the wrong direction. Isaac's energy smacking up against that bermuda high.
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563. CJ5
Well, it looks like Kirk will give the DNC Convention equal weather representation.
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Quoting MississippiWx:
12z Euro...Louisiana/MS border.



Is this the latest run? What are your thoughts on the Euro?
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Quoting bwi:
26.1n 86w latest from HH?

17:52:30Z 26.100N 85.983W 840.9 mb
(~ 24.83 inHg) 1,387 meters
(~ 4,551 feet) - - From 336° at 4 knots
(From the NNW at ~ 4.6 mph)


Which would mean this thing is moving due west... 11AM advisory was 26.1N also.. So why are they saying NW?
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Quoting xtremeweathertracker:
Latest Video Update!! Thanks for Watching!!

Nice job. Very informative video.
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Quoting Grothar:

I'd love one of the learned bloggers to explain the strip of rain on the east side of Florida. ?
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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.