About Jeff Masters
Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 2:27 AM GMT on August 29, 2012
Hurricane Isaac is ashore over Southeast Louisiana, having officially crossed the coast on the Mississippi Delta 90 miles southeast of New Orleans at 7:45 am EDT on August 28. Isaac intensified right up until landfall, striking with 80 mph winds and a central pressure of 970 mb. The storm's large size and large 50 - 60 mile diameter eye kept the intensification rate slow today, but it came quite close to becoming a significantly more dangerous storm. That's because at landfall, Isaac was in the midst of establishing a small inner eyewall within its large 50-mile diameter eye, a very rare feat I've never seen before. Usually, when an eye first forms, it gradually contracts, eventually becoming so small that it becomes unstable. An outer concentric eyewall then forms around the small inner eyewall, eventually becoming the only eyewall when the inner eyewall collapses. But Isaac is a very unusual storm that has continually surprised us, and this inside-out concentric eyewall formation fits the storm's unusual character. The storm isn't in a hurry to move fully inland, and has slowed down to a crawl this evening. This will give the storm the opportunity to keep its center mostly over water a few more hours, and maintain hurricane strength into the early morning on Wednesday.
Figure 1. Radar reflectivity image from New Orleans as Isaac made landfall at 6 pm CDT August 28, 2012.
A dangerous storm surge event underway
Isaac is bringing large and dangerous storm surge to the coast from Central Louisiana to the Panhandle of Florida. At 10 pm EDT, here were some of the storm surge values being recorded at NOAA tide gauges:
6.2' Waveland, MS
9.9' Shell Beach, LA
3.0' Pensacola, FL
4.4' Pascagoula, MS
3.4' Mobile, AL
The 9.9' storm surge at Shell Beach, which is in Lake Borgne 20 miles southeast of New Orleans, exceeds the 9.5' surge recorded there during Category 2 Hurricane Gustav of 2008. Research scientists running a Doppler on Wheels radar located on top of the 16' levees in Plaquemines Parish near Port Sulphur, LA, reported at 8:30 pm EDT that a storm surge of 14' moved up the Mississippi River, and was just 2' below the levees. Waves on top of the surge were cresting over the west side of the levee. Needless to say, they were very nervous. Over the past hour, the surge has retreated some, and waves were no longer lapping over the top of the levee. This is probably due to the fact that we're headed towards low tide. A storm surge of 9.5' has moved up the Mississippi River to the Carrrollton gauge in New Orleans. This is not a concern for the levees in New Orleans, since the storm surge has now brought the river up to 2.5' above its normal water level, which was 7' low due to the 2012 U.S. drought. The highest rise of the water above ground level will occur Wednesday morning over much of Southeast Louisiana, Mississippi, Alabama, and the western Florida Panhandle, when the tide comes back in. It is clear now that this storm surge event will be as dangerous as that of Category 2 Hurricane Gustav of 2008. One piece of good news: NWS New Orleans successfully launched their 00Z balloon. However, their discussion noted the atmosphere is "saturated or nearly saturated" all the way up to 470mb, or 20,000 feet. Precipitable water was 2.76 inches, which will be ripe for extremely heavy rainfall.
Figure 2. Tide gauge data from Shell Beach, located on the south shore of Lake Borgne, just east of New Orleans. The green line shows the storm surge. The red line is the storm tide, the height of the water above Mean Sea Level (MSL.)
Portlight disaster relief charity responds to Issac
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, have mobilized resources in advance of the arrival of Hurricane Isaac. Their crew, including 2 EMTs, is at the Biloxi Special Needs Shelter, and will be caring for shelter dwellers and doing rescues of people who call for help. Another team will be surveying all the shelters in the area to ensure that they are accessible to all people. You can donate to Portlight's disaster relief fund here.
I'll have more in the morning. Hunker down, New Orleans. It's going to be a long night.
Jeff Masters
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.
Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather
1969. nolesjeff
1968. indianrivguy
one unknown design flaw or one rogue wave and they would be getting an award.
1967. VirginIslandsVisitor
Wonderful, just WONDERFUL! Thanks so much for the morning giggle! (And I couldn't agree more!!)
Lindy
1966. oracle28
Dont forget the phrases
DOOM
shower curtain
pinhole eye
bottom-out
fish storm
1965. CaneHunter031472
1964. truecajun
finally kicked the boys off of their football video game so i could watch the news b4 power goes out. wbrz is saying that eye of isaac won't b e here (baton rouge area) until 1AM Thursday morning. we can expect 10-20 inches of rain as we will be on the East side. i thought we were going to be on the West. i guess the wobbles westward overnight changed that.
people shouldn't be on I-10 in the storm area right now, but FWIW, I-10 on both sides is closed at La Place due to water covering the interstate.
1963. HiWay58
Lemmings!
1962. LostTomorrows
But she raced across that stretch of land like nobody's business. She was there and gone in a matter of a few hours.
1961. chrisucf
Best comment so far on this blog.
1960. UnobtrusiveTroll10
I love a good thrill, but as I age I certainly have a better feel for safety and these folks are not being safe. It's all fun and games until...
1959. MisipiGrl
1958. dogsgomoo
General news outlets and news exaggerators brushed him aside or he was mentioned in the context of the Republican convention dodging a wet bullet, or that it's also the anniversary of Katrina/Irene, or here's a few pictures of big waves and people on a beach.
For a time, the story then became about the flooding in Eastern Florida and then South Carolina. Often written up as if it was a separate thing from the storm itself. AP even had a few articles that ended with 'The flooding is unrelated to Tropical Storm Isaac far in the gulf.' WTF AP?
(In hindsight, that convective stall up against the east coast was a preview of Isaac's potential interaction with land. That band of convection literally stalled out and intensified upon land interaction. Even some of the models saw what he was going to do so it will be interesting now to model this storm and it's actual environment to see what made him do that.)
Now, as soon as he was designated a Hurricane the terminology around him changed despite him not having physically intensified all that much (not yet)
And again, I'm talking about the general media, not weather media or weather pros. Suddenly, as a Hurricane, he was "bearing down on" "churning" "threatening" etc.
Now, I'm not saying that the NHC should have designated him a Cat 1 when he was still off the Keys. But I do think the generalized dismissal of 'Tropical Storms' causes a lot of problems and misunderstandings.
The IKE scale needs to be used and I also think that the term Tropical Storm needs to be phased out and replaced with Cat 0 Hurricane.
(Sorry for the length.)
1957. weathermanwannabe
1956. LurkyMcLurkerson
Good thoughts to anybody dealing with this thing.
1955. seafarer459
Ya think ol' Darwin might have been on to something there?
1954. Vindibunny
Link
1953. Masquer08er
1952. thesweetlycool
Pretty cool! Issac is pulling in air all the way from Ohio
1951. LargoFl
1950. Carnoustie
no,one levee which is over topping not breaching.
1949. LargoFl
1948. dixiegal1
Well said! Funny, thoughtful, and TRUE DAT!;) have a safe day everyone!
1947. ckmjreynolds
The landmass between LA and Mobile.
Longbeach, MS.
1946. Charmeck
You want compassion - where is the compassion for the people that have to go out and rescue them?? My heart and prayers go out to everyone - victims and rescue personnel but when evacuations are ordered there is a reason and usually there are evacuation centers that you can go to.
1945. melwerle
Tkeith is okay too.
1944. LargoFl
- Location...29.6N 90.7W or 0 miles SE of Houma, LA
- Max sustained winds: 75mph
- Present movement: NW at 6 mph
- Pressure: 972 MB
by Jennifer - The Storm Report 10:48 AM
1943. DVSmith
Arthur, Bertha and Fran all came ashore at Cape Fear in 1996 (I was living on Oak Island at the time).
Arthur was a TS, Bertha a Cat 1, which had stalled off SC and weakened from a Cat 2, before zipping up the eastern part of the state. Fran slammed ashore as a strong Cat 3 and was still a decent Cat 2 when it went through Durham.
Bonnie, in 1998, made landfall at Cape Fear as a Cat 3 and barely moved, dropping down to a TS, before curving back out to sea as a weak Cat 1 (having strengthened over the sounds).
1942. KRL
1941. MAweatherboy1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1000 AM CDT WED AUG 29 2012
HURRICANE ISAAC IS INLAND OVER SOUTHEASTERN LOUISIANA NEAR HOUMA.
THE CYCLONE HAS MAINTAINED AN IMPRESSIVE RADAR SIGNATURE...WHICH
INCLUDES A RAGGED 40-NMI DIAMETER EYE. CURVED CONVECTIVE RAINBANDS
HAVE INCREASED IN THE EASTERN SEMICIRCLE...AND DOPPLER RADAR
VELOCITIES OF NEAR 80 KT OVER WATER SUPPORT KEEPING ISAAC AS A
MINIMAL HURRICANE FOR THIS ADVISORY. SIMILAR DOPPLER VELOCITIES
OVER LAND AND OVER LAKE PONTCHARTRAIN SUGGEST WIND GUSTS TO NEAR 80
KT COULD OCCUR INLAND OVER SOUTHEASTERN LOUISIANA INTO THIS
AFTERNOON. BY LATE THIS AFTERNOON OR EVENING...HOWEVER...ISAAC IS
FORECAST TO WEAKEN TO A TROPICAL STORM...AND BECOME A TROPICAL
DEPRESSION BY THURSDAY NIGHT.
THE INITIAL MOTION ESTIMATE IS 310/5. ISAAC IS EXPECTED TO MOVE
SLOWLY NORTHWESTWARD THROUGH A WEAKNESS IN THE SUBTROPICAL RIDGE
FOR THE NEXT 24 HOURS...AND THEN TURN NORTH-NORTHWESTWARD AND
NORTHWARD AROUND THE WESTERN PERIPHERY OF THE RIDGE BY 36 AND 48
HOURS...RESPECTIVELY. BY 72 HOURS...ISAAC IS FORECAST TO BECOME A
POST-TROPICAL REMNANT LOW PRESSURE SYSTEM THAT SHOULD MOVE
NORTHEASTWARD TO EAST-NORTHEASTWARD WHEN IT WILL BE CAUGHT UP IN
WEAK MID-LATITUDE WESTERLIES. THERE ARE CURRENTLY NO INDICATIONS IN
ANY OF THE MODEL GUIDANCE SUGGESTING THAT ISAAC WILL TAP INTO ANY
BAROCLINIC ENERGY SOURCES THAT COULD RESULT IN EXTRATROPICAL
STRENGTHENING OVER THE CENTRAL UNITED STATES. THE OFFICIAL TRACK
FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY TRACK AND IS JUST EAST
OF THE MODEL CONSENSUS.
SINCE ISAAC IS FORECAST TO MOVE SLOWLY OVER THE NEXT 24-36 HOURS...
THERE WILL BE A PROLONGED THREAT OF FLOODING FROM HEAVY RAINS OVER
THE NORTHERN GULF COAST AREA AND THE SOUTH-CENTRAL UNITED STATES.
NATIONAL OCEAN SERVICE TIDE GAGES INDICATE THAT STORM SURGE HEIGHTS
OF 6 TO 8 FEET ARE STILL OCCURRING ALONG PORTIONS OF THE COAST OF
SOUTHEASTERN LOUISIANA AND MISSISSIPPI. GIVEN THE LONG DURATION
OF ONSHORE FLOW IN THESE AREAS...WATER LEVELS ARE EXPECTED TO REMAIN
HIGH THROUGH TODAY.
A SPECIAL THANKS TO THE CREWS OF THE AIR FORCE RESERVE AND NOAA
HURRICANE HUNTERS WHO FLEW A TOTAL OF 34 HAZARDOUS MISSIONS INTO
ISAAC...WHICH RESULTED IN AN IMPRESSIVE TOTAL OF 95 CENTER FIXES.
FORECAST POSITIONS AND MAX WINDS
INIT 29/1500Z 29.6N 90.7W 65 KT 75 MPH...INLAND
12H 30/0000Z 30.2N 91.4W 55 KT 65 MPH...INLAND
24H 30/1200Z 31.2N 92.2W 45 KT 50 MPH...INLAND
36H 31/0000Z 32.8N 93.1W 30 KT 35 MPH...INLAND
48H 31/1200Z 34.6N 93.5W 25 KT 30 MPH...INLAND
72H 01/1200Z 38.0N 92.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 02/1200Z 40.0N 89.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
120H 03/1200Z 41.0N 85.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
$$
FORECASTER STEWART
1939. CloudGatherer
WTNT44 KNHC 291451
TCDAT4
HURRICANE ISAAC DISCUSSION NUMBER 34
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1000 AM CDT WED AUG 29 2012
HURRICANE ISAAC IS INLAND OVER SOUTHEASTERN LOUISIANA NEAR HOUMA.
THE CYCLONE HAS MAINTAINED AN IMPRESSIVE RADAR SIGNATURE...WHICH
INCLUDES A RAGGED 40-NMI DIAMETER EYE. CURVED CONVECTIVE RAINBANDS
HAVE INCREASED IN THE EASTERN SEMICIRCLE...AND DOPPLER RADAR
VELOCITIES OF NEAR 80 KT OVER WATER SUPPORT KEEPING ISAAC AS A
MINIMAL HURRICANE FOR THIS ADVISORY. SIMILAR DOPPLER VELOCITIES
OVER LAND AND OVER LAKE PONTCHARTRAIN SUGGEST WIND GUSTS TO NEAR 80 KT COULD OCCUR INLAND OVER SOUTHEASTERN LOUISIANA INTO THIS
AFTERNOON. BY LATE THIS AFTERNOON OR EVENING...HOWEVER...ISAAC IS
FORECAST TO WEAKEN TO A TROPICAL STORM...AND BECOME A TROPICAL
DEPRESSION BY THURSDAY NIGHT.
THE INITIAL MOTION ESTIMATE IS 310/5. ISAAC IS EXPECTED TO MOVE SLOWLY NORTHWESTWARD THROUGH A WEAKNESS IN THE SUBTROPICAL RIDGE FOR THE NEXT 24 HOURS...AND THEN TURN NORTH-NORTHWESTWARD AND NORTHWARD AROUND THE WESTERN PERIPHERY OF THE RIDGE BY 36 AND 48 HOURS...RESPECTIVELY. BY 72 HOURS...ISAAC IS FORECAST TO BECOME A POST-TROPICAL REMNANT LOW PRESSURE SYSTEM THAT SHOULD MOVE NORTHEASTWARD TO EAST-NORTHEASTWARD WHEN IT WILL BE CAUGHT UP IN WEAK MID-LATITUDE WESTERLIES. THERE ARE CURRENTLY NO INDICATIONS IN ANY OF THE MODEL GUIDANCE SUGGESTING THAT ISAAC WILL TAP INTO ANY BAROCLINIC ENERGY SOURCES THAT COULD RESULT IN EXTRATROPICAL STRENGTHENING OVER THE CENTRAL UNITED STATES. THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY TRACK AND IS JUST EAST OF THE MODEL CONSENSUS.
SINCE ISAAC IS FORECAST TO MOVE SLOWLY OVER THE NEXT 24-36 HOURS... THERE WILL BE A PROLONGED THREAT OF FLOODING FROM HEAVY RAINS OVER THE NORTHERN GULF COAST AREA AND THE SOUTH-CENTRAL UNITED STATES.
NATIONAL OCEAN SERVICE TIDE GAGES INDICATE THAT STORM SURGE HEIGHTS OF 6 TO 8 FEET ARE STILL OCCURRING ALONG PORTIONS OF THE COAST OF SOUTHEASTERN LOUISIANA AND MISSISSIPPI. GIVEN THE LONG DURATION OF ONSHORE FLOW IN THESE AREAS...WATER LEVELS ARE EXPECTED TO REMAIN HIGH THROUGH TODAY.
A SPECIAL THANKS TO THE CREWS OF THE AIR FORCE RESERVE AND NOAA HURRICANE HUNTERS WHO FLEW A TOTAL OF 34 HAZARDOUS MISSIONS INTO ISAAC...WHICH RESULTED IN AN IMPRESSIVE TOTAL OF 95 CENTER FIXES.
FORECAST POSITIONS AND MAX WINDS
INIT 29/1500Z 29.6N 90.7W 65 KT 75 MPH...INLAND
12H 30/0000Z 30.2N 91.4W 55 KT 65 MPH...INLAND
24H 30/1200Z 31.2N 92.2W 45 KT 50 MPH...INLAND
36H 31/0000Z 32.8N 93.1W 30 KT 35 MPH...INLAND
48H 31/1200Z 34.6N 93.5W 25 KT 30 MPH...INLAND
72H 01/1200Z 38.0N 92.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 02/1200Z 40.0N 89.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
120H 03/1200Z 41.0N 85.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
$$
FORECASTER STEWART
1938. IMA
1937. LargoFl
1936. leftlink
The storm always required a small pressure drop to MAINTAIN wind speed so if the pressure continues to go up (now 972mb at 10am advisory) the winds should come down a lot.
The only factors that could strengthen the storm now would be a quick jog to the south west or some intensification when the eye passes over swampy waters near Morgan City in about 6 hours.
1935. tessa
1934. MahFL
1933. oreodogsghost
(You gotta be from South Louisiana to understand that one)
1932. reedzone
1931. LargoFl
1930. Badmonkey82009
1. You wore out your F5 key.
2. You understand Taz on first reading.
3. The Tampa shield doesn't sound like a minor league sports team's name.
4. You read Aussie's posts with an accent.
5. You know (and care) that Pat's dog had puppies.
6. You can define a westcaster, floridacaster, upcaster and downcaster... with examples.
7. You know that, when it comes to hurricanes, sometimes science is an art.
8. You randomly crave Fresca.
9. Jim Cantore causes you physical pain when he is on TV.
10. You root for a thunderstorm of the CV islands to become a hurricane then you try to steer into open ocean it by sheer force of will.
11. You.stop.noticing.dots.between.words.
12. You find yourself genuinely hoping that people you've never met get through the storm safely.
Thanks to everyone who posts the "good stuff". To everyone affected.. be safe, you are in my thoughts and prayers. Returning to lurking.
1929. NOLAAlyCat
The Neutral Ground is another word for median here in NOLA. Some are very wide. When the streets start flooding we tend to park our cars here.
1928. CloudGatherer
In other goods news, the Corps finally got the last of its 17th Street Canal pumps switched on around an hour ago. The level within the canal has now dropped from 6ft to 4.3ft, and the S&WB can now pump rainwater out of the city and into the canal as fast as necessary.
So that's one entirely-unnecessary-crisis averted.
1927. IMA
1926. canehater1
Neutral Ground=Median-the area between two roadways
1925. icmoore
It did the same thing in FL in a much lesser degree of course. Over on the east coast they had 12" and more in some areas and here in Madeira Beach on the west coast I got about 1 3/4". With Debby I got at least 8" of rain.
1924. ringeaux
The high ground between lanes of a boulevard.
1923. xkcd
My understanding is that the pressure difference is not directly the main cause of storm surge. Pressure alone only accounts for a couple feet in the strongest storms--maybe 10% of the total surge. The majority of it is wind action.
1922. MoldyinMS
1921. NOLAAlyCat
We are hanging in there. Thanks!
1920. MelanieP
yes
1919. IMA