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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"Deluge that flooded Treasure Coast caused by rain band that detached from Isaac and stalled over area - The worst was supposed to be over — until a "wave" of outlying weather from Tropical Storm Isaac stalled, deluging the Treasure Coast and spawning a destructive tornado west of Vero Beach on Monday"
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Here we go again

Quoting treehuggingsister:
Full disclosure. major dad and I are veterans of major Hurricanes Bertha, Fran, Ivan and Dennis (along with others less significant in damage for us, but worth preparing for). Thanks to Irene visiting brother Bingley last year, I thought I would offer up what's worked for us in terms of preparation, both food-wise, house-wise PLUS some of the things folks don't know about, that make life bearable if those winds of almost-September come early. I hope you'll find something that you didn't know before. First up is the heavy lifting.

For Bertha and Fran in NC (Cat 2 and 3, 56 days apart in ’96), we only lived 10 miles inland, were on the eastern side of the storm both times (translation: got beat all to hell), never boarded up and did just fine. The most important thing we did, and have always done, is CLEAR THE AREA OF POTENTIAL FLYING OBJECTS. Anything and everything in our yard AND the neighborhood that could be turned into a missile (including that 100lb garden pot you don’t think can fly…it can), goes into the garage. Bertha came in during the daytime and, along around noon, we got to watch the neighbor’s metal shed explode and fly through our backyard at about 110 mph. That was the only thing we couldn’t control that day that went walkabout, and it would have killed someone if the wind hadn’t been parallel to the house.

************************************************* ************************************************** *******

*What to Do Inside*

Get ALL Your Laundry Done

You can run out of underwear FAST and blow through some serious t-shirts clearing flotsom. Plus, the second the last load is out of the washer, fill it up on it’s largest setting with cold water and STOP it. Voilà. Another source of water for rinse/washing. (The washing machine also makes an EXCELLENT ice cooler if you are space challenged, trust me. Fill it with THAT instead.)

Bathrooms

Scrub EVERY tub SPARKLING With a bleach based cleaner. We use a piece of saran wrap over the stopper, then plug it to make absolutely sure there’s NO leakage, then FILL THAT SUCKER UP. This becomes both relatively clean water to dip out for a sink sponge bath AND the ALL IMPORTANT FLUSH THE TOILET water. (And is ONLY used for…well, not tinkling.) Speaking of which, it doesn’t hurt to have a “Tidy Bowl” beforehand, if there’s a chance the power might be out for DAYS, if you get my drift…
Now, you may get lucky and have a trickle of water like we did after Fran, but the water company may beg you not to use it, because they’re trying to find leaks, or it’s not potable or whatever. (Another reason to HAVE A REAL RADIO: PUBLIC SERVICE ANNOUNCEMENTS CAN SAVE YOUR LIFE)


Creature Comforts

While you’re busy as a bee, I always, ALWAYS recommend setting the thermostat on your A/C (while you have it) as LOW AS YOU CAN POSSIBLY STAND IT.

As in MEATLOCKER. Wearing SWEATS IN AUGUST cold. “But, ths, why?” you ask.

Because the second that power goes out and ALL those anxious people are still in your house in August breathing?

That temp is going to climb and F.A.S.T. And it will suck so bad.

And you will still have HOURS of storm to go, and schmaybe days without power. You’ll thank me....


Much more from our blog (originally written to help w/ Irene): a Soup to Nuts How-To's for Shopping, PLYWOOD BOARDING (WITH PICTURES), Making the Inside and Outside of Your Home SAFE AND Comfortable at my WunderBlog.
Member Since: September 18, 2007 Posts: 0 Comments: 1074
Several orange (60+ kt) barbs SW of the center.
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Quoting tennisgirl08:
Isaac will be a rain and surge event. Kind of like Irene up the East coast. Dr. Rick Knabb on TWC just said 2 days straight of rains.

We need to stop thinking he's going to be a huge wind event.



easy for you to say!! My local Met has stated that we will have 45-70 MPH winds for atleast 36 hrs straight... I am 30 minutes inland from NO. I know that it will not be major damage, but winds this high for that long period of time could be a wind event..GEAUX TIGERS!!!
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Quoting Grothar:
Anybody see a shift in the model forecasts coming?


No, but I'm just catching up. Do you?
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Best I could find for an ascending tropical storm is 978mb for a subtropical in 1978. For pure tropical storm alone, Amy in 1975 hit 981mb. Not bad.

That's for ascending, though. Descending storms will appear to have stronger intensity for lower winds, but that's due to landfall or imminent extratropical/post-tropical conversion. For example, Katrina after landfall was at 961mb as a tropical storm or 1995's Tanya had 972mb prior to losing tropical characteristics.

but now you know.

Flight level readings have gone up again.
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1152. sar2401
Quoting WxLogic:
Gulp of dry air disrupting circulation:



The story of Isaac's life so far....
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some 60kts flightlevel in the SW quad
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1150. flcanes
Quoting Bluestorm5:
Parsh was right... it's still not a hurricane. I think we all jumped the gun on this storm too much.

it should be at 5, if not 11
after that i'm jumping out of the hurricane suite
Member Since: Posts: Comments:
Now we're talking. Plenty of hurricane-force flight level winds as well as some near hurricane-force SFMR readings.

194830 2548N 08627W 8413 01450 //// 152 //// 296054 058 058 022 01
194900 2547N 08628W 8407 01457 //// 154 //// 300061 063 056 019 01
194930 2546N 08629W 8414 01454 //// 154 //// 292059 060 058 014 01
195000 2545N 08631W 8415 01455 //// 152 //// 288062 065 058 013 01
195030 2544N 08631W 8403 01471 //// 161 //// 289060 065 057 012 01
195100 2543N 08633W 8419 01462 //// 168 //// 289061 064 056 009 01
195130 2542N 08634W 8403 01479 //// 171 //// 287066 069 054 008 01
195200 2541N 08635W 8411 01474 //// 170 //// 286072 073 053 007 01
195230 2540N 08635W 8421 01466 //// 179 //// 284073 074 051 006 01
195300 2539N 08636W 8405 01484 //// 181 //// 284072 072 050 005 01
195330 2538N 08637W 8413 01478 //// 185 //// 284070 072 048 006 01
195400 2537N 08638W 8408 01486 //// 181 //// 286071 072 050 006 01
195430 2536N 08639W 8413 01482 //// 174 //// 287069 070 048 007 01
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting AllyBama:
Isaac is starting to get on my nerves and he aint even here yet!


He has been on my nerves. It is cloudy and breezy in Mobile right now.
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Quoting Ameister12:
Woah. Over 20 inches of rain in parts of West Palm County today.
I believe under that is Seflagamma's house.
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1146. Dakster
Quoting Grothar:
Anybody see a shift in the model forecasts coming?


WOuldn't it be funny if Isaac stalled and was then pushed SSE... (I don't think that will happen - but it would be entertaining)
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Quoting PalmBeachWeatherBoy:
Palm Beach County Schools have been cancelled for Tuesday after what some are calling the "Every 100 years storm". Palm Beach Post
The weather today has been worse than yesterday. Did not expect that, especially after they discontinued the tropical storm warning. The tail of Isaac just keeps lining up over the same area. Relentless.
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Quoting Grothar:
Anybody see a shift in the model forecasts coming?


Everything is basically on track for now.
Member Since: July 15, 2006 Posts: 17 Comments: 10284


Title: Heavy rains reopen Baltimore sink hole Source: AP Date: Aug 26, 2012


A Baltimore public works official says two apartments were evacuated after heavy rains reopened a sink hole.

Department of Public Works spokesman Kurt Kocher says the sink hole covers most of the street

[...]

Two apartments above businesses on the north side of the street have been evacuated along with the businesses because the hole has expanded

[...]

The spokesman says heavy rains over the weekend reopened the site where repairs previously had been made to a sinkhole

[...]
Member Since: Posts: Comments:
1142. flcanes
Quoting Grothar:
Anybody see a shift in the model forecasts coming?

east maybe?
Member Since: Posts: Comments:
Parsh was right... it's still not a hurricane. I think we all jumped the gun on this storm too much.
Member Since: Posts: Comments:
Full disclosure. major dad and I are veterans of major Hurricanes Bertha, Fran, Ivan and Dennis (along with others less significant in damage for us, but worth preparing for). Thanks to Irene visiting brother Bingley last year, I thought I would offer up what's worked for us in terms of preparation, both food-wise, house-wise PLUS some of the things folks don't know about, that make life bearable if those winds of almost-September come early. I hope you'll find something that you didn't know before. First up is the heavy lifting.

For Bertha and Fran in NC (Cat 2 and 3, 56 days apart in ’96), we only lived 10 miles inland, were on the eastern side of the storm both times (translation: got beat all to hell), never boarded up and did just fine. The most important thing we did, and have always done, is CLEAR THE AREA OF POTENTIAL FLYING OBJECTS. Anything and everything in our yard AND the neighborhood that could be turned into a missile (including that 100lb garden pot you don’t think can fly…it can), goes into the garage. Bertha came in during the daytime and, along around noon, we got to watch the neighbor’s metal shed explode and fly through our backyard at about 110 mph. That was the only thing we couldn’t control that day that went walkabout, and it would have killed someone if the wind hadn’t been parallel to the house.

************************************************* ************************************************** *******

*What to Do Inside*

Get ALL Your Laundry Done

You can run out of underwear FAST and blow through some serious t-shirts clearing flotsom. Plus, the second the last load is out of the washer, fill it up on it’s largest setting with cold water and STOP it. Voilà. Another source of water for rinse/washing. (The washing machine also makes an EXCELLENT ice cooler if you are space challenged, trust me. Fill it with THAT instead.)

Bathrooms

Scrub EVERY tub SPARKLING With a bleach based cleaner. We use a piece of saran wrap over the stopper, then plug it to make absolutely sure there’s NO leakage, then FILL THAT SUCKER UP. This becomes both relatively clean water to dip out for a sink sponge bath AND the ALL IMPORTANT FLUSH THE TOILET water. (And is ONLY used for…well, not tinkling.) Speaking of which, it doesn’t hurt to have a “Tidy Bowl” beforehand, if there’s a chance the power might be out for DAYS, if you get my drift…
Now, you may get lucky and have a trickle of water like we did after Fran, but the water company may beg you not to use it, because they’re trying to find leaks, or it’s not potable or whatever. (Another reason to HAVE A REAL RADIO: PUBLIC SERVICE ANNOUNCEMENTS CAN SAVE YOUR LIFE)


Creature Comforts

While you’re busy as a bee, I always, ALWAYS recommend setting the thermostat on your A/C (while you have it) as LOW AS YOU CAN POSSIBLY STAND IT.

As in MEATLOCKER. Wearing SWEATS IN AUGUST cold. “But, ths, why?” you ask.

Because the second that power goes out and ALL those anxious people are still in your house in August breathing?

That temp is going to climb and F.A.S.T. And it will suck so bad.

And you will still have HOURS of storm to go, and schmaybe days without power. You’ll thank me....


Much more from our blog (originally written to help w/ Irene): a Soup to Nuts How-To's for Shopping, PLYWOOD BOARDING (WITH PICTURES), Making the Inside and Outside of Your Home SAFE AND Comfortable at my WunderBlog.
Member Since: Posts: Comments:
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 18:26Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 09L in 2012
Storm Name: Isaac (flight in the North Atlantic basin)
Mission Number: 27
Observation Number: 06
A. Time of Center Fix: 27th day of the month at 17:52:10Z
B. Center Fix Coordinates: 26°07'N 85°59'W (26.1167N 85.9833W)
B. Center Fix Location: 252 miles (405 km) to the WSW (239°) from Tampa, FL, USA.
C. Minimum Height at Standard Level: 1,296m (4,252ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 64kts (~ 73.6mph)
E. Location of the Estimated Maximum Surface Wind: 40 nautical miles (46 statute miles) to the NW (318°) of center fix
F. Maximum Flight Level Wind Inbound: From 57° at 54kts (From the ENE at ~ 62.1mph)
G. Location of Maximum Flight Level Wind Inbound: 37 nautical miles (43 statute miles) to the NW (319°) of center fix
H. Minimum Sea Level Pressure: 985mb (29.09 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,538m (5,046ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,544m (5,066ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 0.5 nautical miles
Remarks Section:
Maximum Flight Level Wind: 54kts (~ 62.1mph) in the northwest quadrant at 17:39:00Z
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Quoting LargoFl:
I dont know about you all..but im exhausted lol..been a very hectic day today posting huh...here's another warning......COASTAL FLOOD ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...

THE NATIONAL WEATHER SERVICE IN TAMPA BAY RUSKIN HAS ISSUED A
COASTAL FLOOD ADVISORY...WHICH IS IN EFFECT UNTIL 8 PM EDT THIS
EVENING.

* COASTAL FLOODING...1 TO 3 FEET ABOVE NORMAL TIDES.

* TIMING...THROUGH THIS EVENING.

* IMPACTS...MINOR FLOODING RIGHT ALONG THE COAST DURING HIGH
TIDES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A COASTAL FLOOD ADVISORY INDICATES THAT ONSHORE WINDS AND TIDES
WILL COMBINE TO GENERATE FLOODING OF LOW AREAS ALONG THE SHORE.

&&


Good job getting the word out Largo. :)
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1137. Grothar
Anybody see a shift in the model forecasts coming?
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Quoting JasonRE:


Redbull, I hear ya. Where are you located again? I'm in Lafayette. I think you are too. Nobody around here is doing anything, which is surprising me. I know it's only a Cat. 1, and we are about in the center or just West of the center for landfall, but really? Just, oh yeah, we'll be fine......oh it won't be bad, etc etc.....I'm getting sandbags myself.

Jason - actually, people are doing quite a bit. The news reports show people are buying supplies and generators, and even some gas stations here are running out of or are low on gas.
You'll see a surge in people shopping tonight if they track shifts further west.
Try not to worry ... these situations can cause extra stress.
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1135. flcanes
Quoting Bielle:
Is anybody talking about the great blob over west-central Florida? Is it still following Isaac? Is there some way of seeing where it is headed? (I can't access the NOAA sites.) Thanks

no, it is not following isaac, and it is headed nne
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Member Since: September 18, 2007 Posts: 0 Comments: 1074
1133. LargoFl
Member Since: August 6, 2011 Posts: 4 Comments: 42029



16:05 GMT
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Isaac is starting to get on my nerves and he aint even here yet!
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1130. Bielle
Is anybody talking about the great blob over west-central Florida? Is it still following Isaac? Is there some way of seeing where it is headed? (I can't access the NOAA sites.) Thanks
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Quoting MiamiHurricanes09:
No you're completely correct, I observed the raw data incorrectly that lead me to believe it was stationary. A NNE-ward jog has occurred between penetrations.

LOL, I'll be retreating back to my cave now. ;)


LOL. No need for that :-)
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Good thing that we almost have round the clock recon in the storm to keep the data and fixes accurate. He does appear to have slowed down a little bit (looking at an hour long radar loop to my eyes) from the 1:00 CDT advisory (14 mph) but looks can be deceiving. I will be real curious to see what the speed will be at 5:00/4:00 CDT.
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Sinkhole: Assumption Parish called on to evacuate ahead of storm — Official Website: “More information will follow!!!”

Published: August 27th, 2012 at 2:09 am ET
Title: State of emergency
Source: The Advocate
Author: Robert Stewart
Date: Aug 27, 2012

[...]

The parishes Jindal called on to evacuate are: Ascension, Assumption, Jefferson, Lafourche, Livingston, Plaquemines, Orleans, St. Bernard, St. Charles, St. James, St. John, St. Tammany, Tangipahoa, Terrebonne and Washington.

[...]

[Louisiana Governor Bobby] Jindal said he expects he will have to declare mandatory evacuations for the parishes after state officials meet again Monday morning.

State government offices in those 15 parishes will be closed Monday, the state Division of Administration said in a news release.

[...]

Jindal said the state Department of Natural Resources is working with Texas Brine Co. LLC of Houston to make sure equipment at the site and surrounding areas of a massive sinkhole in Assumption Parish are secure.
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Quoting WxLogic:
Gulp of dry air disrupting circulation:



Looks a lot better organized, though.
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Quoting MississippiWx:
Recon finds that the center has moved to the NNE since the last fix. The center is being tossed around by the convection that's wrapping around it.


Watching the IR loop you can see the eye trying to come through and also see it bounce to the NE. It has been trying hard all day to form an eyewall but maybe it is the NE quadrant that is having the issues.
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Quoting kmanislander:


I dont think so. The obs from the HH now show WSW winds to the NE of the first center dropsonde position.
This suggests a center reformation. The white pin in the data set to the NE of the first drop should be the new center position I would think as obs to the N and S of that "pin" show winds from the E and W respectively.
No you're completely correct, I observed the raw data incorrectly that lead me to believe it was stationary. A NNE-ward jog has occurred between penetrations.

Quoting MississippiWx:


Of course I'm right. Back off me, MH. :-)
LOL, I'll be retreating back to my cave now. ;)
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting flcanes:

i've got to say thanks to him too
Quoting ILwthrfan:

Thanks GT. This be my #1 Bookmark during Hurricane season now. Thank you.

No problem guys anyway I can help. I come on here too learn as well.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting hurricanehanna:
I'm just not seeing the NW movement...been staring at it too long I guess. Seems to be more WNW or W


Yep. That, young Jedi, is the force of true understanding, when you can see past the imposed will of the PC weather-police...to be aware of every potential. lol.
Yeah, why not just admit it & prepare for the possibilities? Why? Because that all costs a lot. Consider all the $$$$ that this storm could be costing people already, from SW Florida to New Orleans now! It takes money to rev up preparedness. We are in a recession. You look west of New Orleans, and there are millions more people that could cost much more $$$$ to prepare for a possible landfall.

Preparing for this storm possibly - even possibly - going further west now when it MIGHT simply duck into LA with a little wet duck-splash...is NOT politically correct. The dangers to careers possibly for doing or saying too much & costing too much $$$$ is there perhaps as well as the possibility of what happens if they don't play it safe, the storm revs up big & slams Houston/Galv. or Beaumont/PortArthur powerfully & unexpectedly.

Consider the angle of attack. How many degrees difference at this angle between hitting those places or the Big Easy? Not much. How many more hours of preparation time will the TX cities get if it does go that way? Possibly few, especially with many people there already figuring this thing's heading to New Orleans -- after all, that's what the news has been saying like they know it for a fact, it seems. Foolishness. Don't forget that Galveston has a very dreadful history of unexpected hurricane sufferings.
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1121. Caner
Quoting GTcooliebai:
If it continues on a NW heading it could come in East of NOLA around Gulfport.


Current track seems to support that, but several models call for a gradual westerning of the track nearer to landfall.
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1120. CJ5
He looks better than he has in a while. I believe there is some slow down and slight N movement. Maybe he will be able to catch his breath and get going. Convection seems to have wrapped around but the trick will be if it can stay. Lower pressure should bring high winds eventually if he can spin up tighter.
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Quoting watchdog40:
Ok, starting to worry, local radio has said it could shift back east tward the pens al border, does nayone here agree with that?

None of the models support that.
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1118. WxLogic
Gulp of dry air disrupting circulation:

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1117. robj144
Here's a video I took last night in Palm Beach County to demonstrate how much rain was coming down at times:

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Woah. Over 20 inches of rain in parts of West Palm County today.
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1115. flcanes
Quoting Dakster:


I guess the forecasted stall has now happened?

i guess this could be good?
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In the same way that storms can be evaluated with a single term describing total kinetic energy, I am wondering if storms might be also usefully described by a figure that referred to the total displacement (lower pressure) of atmosphere from the average?

The reason that I bring this up is that it seems that the pressure for Issac is plenty low to support at cat 1 storm.... yet the wind is not there yet. If I remember rightly, this same sort of thing was the case with Opal some years back ... it was still a nominal affair off in the gulf, but looking at the weirdly stretched out swells coming in at the beach in Venice Fl, I got a direct perceptual sense that the lowering pressure was a very broad thing. It seems like the lowering pressure can suddenly collect itself toward the center ... seemingly precipitating RI but really the muscle for the storm was already there... just not collected and expressed in wind speed yet.
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Quoting Neapolitan:
I'm not the blog police, and far be it from me to stomp on anyone's fun, but I personally find the repeated jokes about Stephanie Abrams' body to be tasteless and disrespectful. I understand that some may not like her, and that's their choice. I also understand that some may find her attractive. That, too, is their choice. But the woman is a professional, not some bimbo posing for the cover of Maxim; she's got degrees in meteorology and geography (along with a minor in mathematics, fer cryin' out loud). As often as met students in this forum talk about how difficult those courses are, I'd think Ms Abrams would deserve at least here to be talked about for what she's accomplished more than the physical attributes gifted to her by her DNA. Not to mention: there aren't just hormonal males frequenting this forum. So can you guys maybe save the female body worship for WU mails or your own blogs? Please?

Thank you, Neapolitan.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
1112. flcanes
Quoting kmanislander:


I dont think so. The obs from the HH now show WSW winds to the NE of the first center dropsonde position.
This suggests a center reformation. The white pin in the data set to the NE of the first drop should be the new center position I would think as obs to the N and S of that "pin" show winds from the E and W respectively.

i suspect u are right
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1111. Dakster
Quoting MiamiHurricanes09:
Center is stationary.



I guess the forecasted stall has now happened?
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Ok, starting to worry, local radio has said it could shift back east tward the pens al border, does nayone here agree with that?
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Quoting ILwthrfan:

Thanks GT. This be my #1 Bookmark during Hurricane season now. Thank you.
I like the HWRF model too because of its nested grid and it can even pan out to the rest of the Tropical Atlantic.
Member Since: August 31, 2009 Posts: 0 Comments: 5628

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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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