11 ms·

Hurricane Ida could be close to Cat 4, dump up to 20“ of rain in S.E. Louisiana

123 points by lsllc 5y ago

UncleOxidant 5y ago
"Tropical Storm Ida could be close to Category 4 hurricane strength when it makes landfall Sunday on Louisiana's coast" "Sunday is the 16th anniversary of Hurricane Katrina."
- gsibble 5y ago
  Oof.
  - benatkin 5y ago
    It's not a huge coincidence, because it's hurricane season. There's a graph here, under "Number of Tropical Cyclones per 100 Years": https://www.nhc.noaa.gov/climo/ https://www.nhc.noaa.gov/climo/
- jandrese 5y ago
  Having Hurricanes reach maximum average strength about the same time every year isn't that big of a surprise.
post_break 5y ago
Houston dodging more bullets than Neo in the matrix. I'm glad but feel bad for our neighbors.
- yuy910616 5y ago
  If I remember correctly, he only successfully dodged 2/3 bullets. And then he started to stopping them
- ubermonkey 5y ago
  I mean, we DID get Harvey. My lay take here is that the flow of the Gulf Stream tends to bend the storms to the east as they approach the coast, so you get these curveball tracks that, unfortunately, disproportionately seem to smack Louisiana and Mississippi. Harvey came ashore further south, and so the eastward movement caught us (though that's a gross oversimplification of Harvey's actual mechanics).
  - post_break 5y ago
    Yeah but Harvey was mostly rain. If we had a category 5 go up the ship channel the entire US would be impacted. So much oil, fuel, etc goes through here.
    - ubermonkey 5y ago
      Fair. I was just thinking in terms of local impact.
Althuns 5y ago
There's still flooding from last week's storm in TN...
- h2odragon 5y ago
  They found the last person yesterday: https://abcnews.go.com/US/wireStory/fema-administrator-tours-tennessee-flooding-disaster-79643298 https://abcnews.go.com/US/wireStory/fema-administrator-tours... The word is that the railroad embankment acted as a temporary levee and stored a large charge of water up, until it failed. Then this impromptu lake charged right through town. It's usual for that are to flood, this was just a lot more water all at one time than usual. There were pictures of cars filled with gravel; and that rail berm blown completely out, tracks dangling.
taylorlapeyre 5y ago
What some might not know is that New Orleans is currently extremely unprepared for a major hurricane. Some water pumps are offline, and the city is currently in the middle of a huge amount of road and infrastructure work. Flooding will likely be much worse for this storm than normal. If you're in New Orleans, I recommend considering an evacuation if you have somewhere to go.
- selimthegrim 5y ago
  Most people I know here are staying at present. If it is Cat 4+ that might change.
  - AdamN 5y ago
    This is what I hate about the category system - it's entirely wind based and while that's important, rainfall and direction of wind (for coasts) is what's most important. Cat 2 can be worse than Cat5 also because they move slower so more inches of rain per hour.
    - interestica 5y ago
      Interestingly, the Enhanced Fujita scale (EF) used for tornadoes takes into account damage as well as wind speed. Maybe something like that would be more appropriate for hurricanes. An 'enhanced' saffir-simpson scale? https://www.weather.gov/oun/efscale https://www.weather.gov/oun/efscale
      - beerandt 5y ago
        It already does. There's no problem with the system, for people that understand what it is meant to describe. Rainfall isn't a part of that. The best way to describe rainfall is by... giving the rates and cumulative amount of rainfall. Flash flood warnings exist when excessive rain causes... flash flooding. As for direction: hurricanes are circles. Everyone knows the east eyewall is the worst part. Idk what else you'd want to incorporate/describe that's useful. Except that people that haven't been through bad hurricanes always think what they experience must be worse than the category of the storm. Eg: Sandy not being hurricane strength when it came ashore, so they made up the term "Superstorm Sandy" because "just" tropical storm somehow lessons their experience.
coding123 5y ago
https://www.windy.com/-Rain-accumulation-rainAccu?rainAccu,36.049,-92.109,5 https://www.windy.com/-Rain-accumulation-rainAccu?rainAccu,3... Click on "Next 10 Days" near the bottom. Windy users know about this stuff way farther in advance.
- joshcrews 5y ago
  Another endorsement of Windy. In 2017 Windy knew that Hurricane Harvey was going to stall out over SE Texas days in advance.
  - cos2pi 5y ago
    Windy doesn’t make forecasts, rather it visualizes output from forecast models.
    - dghlsakjg 5y ago
      Yup. You can even choose different models for it to visualize!
- mastax 5y ago
  "People who look at forecast maps" know about this stuff way further in advance, surely. That said, Windy is very good.
  - dylan604 5y ago
    "People who look at forecast maps" are way more confused about the weather actually happening than those that don't. FTFY ;-) My local forecasts have predicted rain for multiple days in a row, and then those days arrive to sunny skies. The same day forecasts get updated to reflect the lack of rain, and then mid-to-late afternoon storms after zero prediction of them. This summer has been a bad luck streak for forecasters.
  - jeffbee 5y ago
    Windy makes a compelling visualization of data that is often totally wrong and misleading. Their presentation of PM2.5 concentrations in California right now is very pretty and also off by about an order of magnitude versus actual sensor readings. I will continue to prefer the much uglier but correct presentations from NOAA themselves, or the incredibly slow but rich and accurate data from wunderground.
chooseaname 5y ago
The gulf is HOT right now. And that heat goes pretty deep. I wonder if we'll see a Michael situation, where Ida just continues to intensify as it closes in on land.
- dylan604 5y ago
  Isn't that precisely what the model shows it doing?
- lsllc 5y ago
  SSTs are 30-32°C (86-90°F) in the GoM right now: https://ocean.weather.gov/Loops/SST_GMex_SST/image_2021082701.png https://ocean.weather.gov/Loops/SST_GMex_SST/image_202108270...
  - dustingetz 5y ago
    Sea Surface Temperature I'm sorry, you're saying the ocean surface is hotter than a heated pool right now? What is the baseline?
    - finiteseries 5y ago
      https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_ts.php https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_ts.php ~26C mean ranging from 23C in February to 30C in August.
    - lsllc 5y ago
      Pretty much. A couple of summers ago I stayed for a late August weekend at Hilton Head S.C. and going into the ocean was like getting into a hot tub. It was actually too warm, not at all refreshing from the 100+F day -- the Hotel pool was much cooler. It was really eye-opening actually.
    - brk 5y ago
      The GoM gets pretty warm (I live on the water just off the GoM proper (Boca Ciega Bay)). Late summer temps in the upper 80s or low 90s are common. Our pool used to heat to 95 before the shade palms grew up. I Don think I can recall the surface temp being less than 80 often, based on the data from my depth sonar on the boat at random times during the ‘winter’.
nixpulvis 5y ago
How does this 20" of rain compare to Katrina? https://svs.gsfc.nasa.gov/3221 https://svs.gsfc.nasa.gov/3221
- jeffbee 5y ago
  I don't know but the scale of that viz only goes to 80mm, which is only 3 inches. The forecast for the river in New Orleans suggest no flooding this week. https://water.weather.gov/ahps2/hydrograph.php?wfo=lix&gage=norl1 https://water.weather.gov/ahps2/hydrograph.php?wfo=lix&gage=...
- dredmorbius 5y ago
  Hurricane Katrina saw 15" of rain over New Orleans in 2005, though a higher storm surge was measured (14') than what is predicted for Ida (7--11'). https://en.wikipedia.org/wiki/Hurricane_Katrina https://en.wikipedia.org/wiki/Hurricane_Katrina http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf [pdf] There are multiple factors that come into play. There's storm surge and tides. Tides around Morgan City are pretty modest (less than 1/2 foot / 15cm total range), and will be low as the storm arrives. Storm surge forcast is 7-11 ft per NOAA. Given the extreme low-lying land, that's significant. I don't have comparative numbers for Katrina offhand. The total rainfall amount is one. The period of time over which it falls, and where the storm goes afterward are also critical. Ida looks to be slow-moving, and is presently slated to track pretty much directly up the Mississippi river, then over the Ohio River Valley. That means there's going to be heavy river flow coming downstream possibly for several weeks after the storm itself passes. I'd predicted and observed a similar trend when Hurricane Florence hit Wilmington, NC, in 2018, and upstream-based water flows contributed to flooding, and issues such as hog farm sludge empoundments (basically: pig shit lakes) in the region. For Louisiana, the concern is probably more petroleum refining and chemical plants. Note that Florence hung around for days. Ida looks as if it will stick around Southern Louisiana for about 18 hours, then start accelerating to the NNE, though remaining over the drainage baisin feeding into New Orleans.
cryptoz 5y ago
I am collecting data on this storm using barometers in Android devices with All Clear Weather: https://play.google.com/store/apps/details?id=com.allclearweather.android https://play.google.com/store/apps/details?id=com.allclearwe... If you want to join, you can download the app and go to Settings->Sensors to enable. Here's an animation I made of Hurricane Dorian a couple years ago as it approached the coast of Florida: https://www.allclearweather.com/hurricane-dorian https://www.allclearweather.com/hurricane-dorian And of course, there are recent scientific papers showing that this kind of data (barometric pressure from phones) could be useful in general weather forecasting to improve accuracy: Smartphone Pressure Collection and Bias Correction Using Machine Learning: https://journals.ametsoc.org/doi/full/10.1175/JTECH-D-17-0096.1 https://journals.ametsoc.org/doi/full/10.1175/JTECH-D-17-009... Impacts of Assimilating Smartphone Pressure Observations on Forecast Skill during Two Case Studies in the Pacific Northwest: https://journals.ametsoc.org/doi/full/10.1175/WAF-D-18-0085.1 https://journals.ametsoc.org/doi/full/10.1175/WAF-D-18-0085....
meepmorp 5y ago
Look at a fancy view of the current forecast and other data here: https://cwcgom.aoml.noaa.gov/cgom/OceanViewer/index_phod.html https://cwcgom.aoml.noaa.gov/cgom/OceanViewer/index_phod.htm... edit: the sea surface temps are nuts
- consumer451 5y ago
  > the sea surface temps are nuts Can you imagine what these temps will look like if the Gulf Stream slows/shuts downs as predicted?
- michaelbuckbee 5y ago
  Can you expand on that a bit, I don't have any context to understand how far out of whack it is?
  - baq 5y ago
    It’s a almost as bad as it could be. The only thing that could make this worse is of the hurricane slowed down over the gulf and stayed there for a couple days.
- lnwlebjel 5y ago
  Wow, hadn't seen this before. Thanks for posting it.
- cjdaly 5y ago
  here is a satellite view I've been watching, also from NOAA: https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=gm&band=GEOCOLOR&length=150 https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G1...
  - fuzzfactor 5y ago
    That's the geostationary view of the gulf. Here's the "floater" that stays overhead of the storm as it comes ashore: https://www.star.nesdis.noaa.gov/goes/floater.php?stormid=AL092021 https://www.star.nesdis.noaa.gov/goes/floater.php?stormid=AL...
Karupan 5y ago
Genuine question since I don’t live in a city which experiences severe weather events annually: what is the financial incentive in rebuilding destroyed homes, businesses and other infrastructure every few years? Does that actually lead to a net positive outcome for those affected in the long run?
- dghlsakjg 5y ago
  Most of the time it isn't the same places that get hit. Its not as if the same neighborhood is rebuilt year after year, many of these places have homes and infrastructure that is 100 years old. Also keep in mind that a majority of the East Coast is under threat from Hurricanes. If we just abandoned any area that has been severely damaged by a hurricane, there would effectively be an unpopulated coastline from Boston to the Mexican border.
  - acdha 5y ago
    There are steps between doing nothing and abandoning the east coast. There are some areas (right at sea level, river flood zones) which probably are better off as parks, and letting things like costal mangrove forests regrow would be important, but there’s a lot of places where a significant fraction of the existing buildings could remain viable if they were sensibly built following good design practice rather than as cheaply as the developers could get away with. It seems like something flood insurance and building codes should get increasingly stringent about, similar to how some California fire codes started requiring houses to be built to support sheltering in place during wildfires so you didn’t have so many people evacuating and needing to rebuild as many homes. It’d be nice if that started as guaranteed annual premium increases for unsafe properties with an assistance program for primary residences which phases out based on property value.
- nolaspring 5y ago
  Moral hazard has entered the chat.
  - dredmorbius 5y ago
cos2pi 5y ago
For the interested, real-time data from the ongoing aircraft reconnaissance into (now) Hurricane Ida can be seen at https://www.tropicaltidbits.com/recon https://www.tropicaltidbits.com/recon
- baq 5y ago
  tropicaltisbits.com also hosts the author’s blog which is well worth following when major storms are present near the GOM.
claaams 5y ago
Good thing southern hospitals have a lot of space for casualties right now.. .
- dredmorbius 5y ago
  https://www.worldometers.info/coronavirus/usa/louisiana/ https://www.worldometers.info/coronavirus/usa/louisiana/ https://www.nytimes.com/interactive/2021/us/louisiana-covid-cases.html https://www.nytimes.com/interactive/2021/us/louisiana-covid-... 2,600 hospitalisations presently.
- cmpb 5y ago
  Yeah it is potentially a really bad situation right now in Louisiana. We have been getting our vax numbers up recently and the hospitalizations have started to come down in the past week or so, but not by much. With catastrophic hurricanes, though, what I've noticed is that we have lots of refugees (and deaths, in the case of Katrina) compared to hospitalizations. New Orleans can also turn the large arena areas (e.g. Superdome, Zephyr Field) into mass casualty and refugee areas immediately following the storm, which should help with keeping the hospitals from getting overrun.
  - dredmorbius 5y ago
    The problem with refugees is crowding, displacement, lack of resources, and lack of communications. These tend to exacerbate any extant public health situations. Given general incompetence concerning Covid in the Southern US generally, I've certain concerns. What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota, then radiated outwards, toward the coasts and south, over the course of the winter, peaking around 10 Januare 2021. I've speculated that mass events, travel, return to school, and greater indoor activity (heating season in the north, as opposed to cooling season in the south) also contributed. This year the US might se a dual hotspot originating in Sturgis and Louisiana, both radiating outward. Something to keep tabs on.
    - jdminhbg 5y ago
      > What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota Is there any actual evidence for this?
dredmorbius 5y ago
I've been following the storm via Nullschool and its forecast model (GFS). Landfall of the eye has shifted about 40km westward, been delayed by about 6+ hours relative to the forecast 18 hours ago, and increased in intensity. The green circle here represents where the eyewall landfall was previously forecast to occur at about noon CST. Current forecast shows landfall at Jack Stout Bay, south of Morgan City, and tracking about 40km west of New Orleans proper. The area of landfall has been hit by several storms in the past several years, is mostly smaller settlements, and there are probably numerous already-damaged or only partially-repaired structures. https://earth.nullschool.net/#2021/08/29/1700Z/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-90.45,28.89,5202/loc=-90.074,29.475 https://earth.nullschool.net/#2021/08/29/1700Z/wind/surface/...
- AdamN 5y ago
  The problem is that the eye is not the most damaging part, it's the right side of the eye that's funneling water from the Gulf onto the land that's got the most damage potential. From that link it looks like New Orleans is in a much worse situation than if it were to receive a direct hit.
  - dredmorbius 5y ago
    There's that. A near-westward hit could be more damaging than a direct strike, largely based on storm surge and possibly wind speeds. What the maximal high-damage offset distance is I don't know, though 20--40km seems sufficiently close to be bad. I'd suspect a little nearer would be worse. And I do wonder just how many more storms Nawlins and the Old River Structure have in them.
- deleted 5y ago
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- dls2016 5y ago
  Whoa! This site is rad! I often thought about making something like this. It always seems like the for-pay weather apps are crap but all the data is freely available.
b8 5y ago
I live in Louisiana, and attended Tulane for a while. Some streets around Tulane floods after a few hours of rain. I hope that every who lives in NOLA or high risk areas just goes ahead and leaves for right now. Some people tried to stay and party during Katrina. Hopefully folks don't make the same mistake twice...
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MisterBastahrd 5y ago
There's nothing to be happy about when a hurricane is bearing down on you, and it's worse when you're caught on the east side of the storm with heavy rains because the winds blow counter clockwise, meaning that rivers and streams and lakes that open or drain into the Gulf of Mexico will pile up and keep getting higher as long as the story is over the area. Southeast Louisiana can take 20 inches of rain over a few days, but not when there's no place for the water to go.
Fordec 5y ago
Louisiana is just going to lose so much territory between now and the end of the century to the ocean. Their shorelines are just too shallow to deal with the hurricanes and rising sea levels that are coming.
- dredmorbius 5y ago
  A pretty good chunk of what's mapped as land in Louisiana isn't. The map lies. https://medium.com/matter/louisiana-loses-its-boot-b55b3bd52d1e https://medium.com/matter/louisiana-loses-its-boot-b55b3bd52... http://samuel-warde.com/2018/10/louisiana-maps-are-all-a-lie-the-true-map-is-frightening/ http://samuel-warde.com/2018/10/louisiana-maps-are-all-a-lie... https://www.businessinsider.com/real-map-louisiana-should-scare-you-2017-6?op=1 https://www.businessinsider.com/real-map-louisiana-should-sc... https://yewtu.be/watch?v=ZBGYb5An8Mo https://yewtu.be/watch?v=ZBGYb5An8Mo
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WaltPurvis 5y ago
The National Hurricane Center has updated the forecast for Ida and now calls for it to be a 140 MPH Cat 4 (or greater) at landfall. The previous forecast had Ida topping out as a 120 MPH Cat 3. Storm surge of 10 to 15 feet above ground level will impact a broad area. https://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/271449.shtml https://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/271449...
- selimthegrim 5y ago
  Well I hope the trucker motels in West Memphis aren't full.

123 points by lsllc 5y ago

"Tropical Storm Ida could be close to Category 4 hurricane strength when it makes landfall Sunday on Louisiana's coast" "Sunday is the 16th anniversary of Hurricane Katrina."

gsibble 5y ago
Oof.
- benatkin 5y ago
  It's not a huge coincidence, because it's hurricane season. There's a graph here, under "Number of Tropical Cyclones per 100 Years": https://www.nhc.noaa.gov/climo/ https://www.nhc.noaa.gov/climo/
jandrese 5y ago
Having Hurricanes reach maximum average strength about the same time every year isn't that big of a surprise.

post_break 5y ago

Houston dodging more bullets than Neo in the matrix. I'm glad but feel bad for our neighbors.

yuy910616 5y ago
If I remember correctly, he only successfully dodged 2/3 bullets. And then he started to stopping them
ubermonkey 5y ago
I mean, we DID get Harvey. My lay take here is that the flow of the Gulf Stream tends to bend the storms to the east as they approach the coast, so you get these curveball tracks that, unfortunately, disproportionately seem to smack Louisiana and Mississippi. Harvey came ashore further south, and so the eastward movement caught us (though that's a gross oversimplification of Harvey's actual mechanics).
- post_break 5y ago
  Yeah but Harvey was mostly rain. If we had a category 5 go up the ship channel the entire US would be impacted. So much oil, fuel, etc goes through here.
  - ubermonkey 5y ago
    Fair. I was just thinking in terms of local impact.

Althuns 5y ago

There's still flooding from last week's storm in TN...

h2odragon 5y ago
They found the last person yesterday: https://abcnews.go.com/US/wireStory/fema-administrator-tours-tennessee-flooding-disaster-79643298 https://abcnews.go.com/US/wireStory/fema-administrator-tours... The word is that the railroad embankment acted as a temporary levee and stored a large charge of water up, until it failed. Then this impromptu lake charged right through town. It's usual for that are to flood, this was just a lot more water all at one time than usual. There were pictures of cars filled with gravel; and that rail berm blown completely out, tracks dangling.

taylorlapeyre 5y ago

What some might not know is that New Orleans is currently extremely unprepared for a major hurricane. Some water pumps are offline, and the city is currently in the middle of a huge amount of road and infrastructure work. Flooding will likely be much worse for this storm than normal. If you're in New Orleans, I recommend considering an evacuation if you have somewhere to go.

selimthegrim 5y ago
Most people I know here are staying at present. If it is Cat 4+ that might change.
- AdamN 5y ago
  This is what I hate about the category system - it's entirely wind based and while that's important, rainfall and direction of wind (for coasts) is what's most important. Cat 2 can be worse than Cat5 also because they move slower so more inches of rain per hour.
  - interestica 5y ago
    Interestingly, the Enhanced Fujita scale (EF) used for tornadoes takes into account damage as well as wind speed. Maybe something like that would be more appropriate for hurricanes. An 'enhanced' saffir-simpson scale? https://www.weather.gov/oun/efscale https://www.weather.gov/oun/efscale
    - beerandt 5y ago
      It already does. There's no problem with the system, for people that understand what it is meant to describe. Rainfall isn't a part of that. The best way to describe rainfall is by... giving the rates and cumulative amount of rainfall. Flash flood warnings exist when excessive rain causes... flash flooding. As for direction: hurricanes are circles. Everyone knows the east eyewall is the worst part. Idk what else you'd want to incorporate/describe that's useful. Except that people that haven't been through bad hurricanes always think what they experience must be worse than the category of the storm. Eg: Sandy not being hurricane strength when it came ashore, so they made up the term "Superstorm Sandy" because "just" tropical storm somehow lessons their experience.

coding123 5y ago

https://www.windy.com/-Rain-accumulation-rainAccu?rainAccu,36.049,-92.109,5 https://www.windy.com/-Rain-accumulation-rainAccu?rainAccu,3... Click on "Next 10 Days" near the bottom. Windy users know about this stuff way farther in advance.

joshcrews 5y ago
Another endorsement of Windy. In 2017 Windy knew that Hurricane Harvey was going to stall out over SE Texas days in advance.
- cos2pi 5y ago
  Windy doesn’t make forecasts, rather it visualizes output from forecast models.
  - dghlsakjg 5y ago
    Yup. You can even choose different models for it to visualize!
mastax 5y ago
"People who look at forecast maps" know about this stuff way further in advance, surely. That said, Windy is very good.
- dylan604 5y ago
  "People who look at forecast maps" are way more confused about the weather actually happening than those that don't. FTFY ;-) My local forecasts have predicted rain for multiple days in a row, and then those days arrive to sunny skies. The same day forecasts get updated to reflect the lack of rain, and then mid-to-late afternoon storms after zero prediction of them. This summer has been a bad luck streak for forecasters.
- jeffbee 5y ago
  Windy makes a compelling visualization of data that is often totally wrong and misleading. Their presentation of PM2.5 concentrations in California right now is very pretty and also off by about an order of magnitude versus actual sensor readings. I will continue to prefer the much uglier but correct presentations from NOAA themselves, or the incredibly slow but rich and accurate data from wunderground.

chooseaname 5y ago

The gulf is HOT right now. And that heat goes pretty deep. I wonder if we'll see a Michael situation, where Ida just continues to intensify as it closes in on land.

dylan604 5y ago
Isn't that precisely what the model shows it doing?
lsllc 5y ago
SSTs are 30-32°C (86-90°F) in the GoM right now: https://ocean.weather.gov/Loops/SST_GMex_SST/image_2021082701.png https://ocean.weather.gov/Loops/SST_GMex_SST/image_202108270...
- dustingetz 5y ago
  Sea Surface Temperature I'm sorry, you're saying the ocean surface is hotter than a heated pool right now? What is the baseline?
  - finiteseries 5y ago
    https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_ts.php https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_ts.php ~26C mean ranging from 23C in February to 30C in August.
  - lsllc 5y ago
    Pretty much. A couple of summers ago I stayed for a late August weekend at Hilton Head S.C. and going into the ocean was like getting into a hot tub. It was actually too warm, not at all refreshing from the 100+F day -- the Hotel pool was much cooler. It was really eye-opening actually.
  - brk 5y ago
    The GoM gets pretty warm (I live on the water just off the GoM proper (Boca Ciega Bay)). Late summer temps in the upper 80s or low 90s are common. Our pool used to heat to 95 before the shade palms grew up. I Don think I can recall the surface temp being less than 80 often, based on the data from my depth sonar on the boat at random times during the ‘winter’.

nixpulvis 5y ago

How does this 20" of rain compare to Katrina? https://svs.gsfc.nasa.gov/3221 https://svs.gsfc.nasa.gov/3221

jeffbee 5y ago
I don't know but the scale of that viz only goes to 80mm, which is only 3 inches. The forecast for the river in New Orleans suggest no flooding this week. https://water.weather.gov/ahps2/hydrograph.php?wfo=lix&gage=norl1 https://water.weather.gov/ahps2/hydrograph.php?wfo=lix&gage=...
dredmorbius 5y ago
Hurricane Katrina saw 15" of rain over New Orleans in 2005, though a higher storm surge was measured (14') than what is predicted for Ida (7--11'). https://en.wikipedia.org/wiki/Hurricane_Katrina https://en.wikipedia.org/wiki/Hurricane_Katrina http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf [pdf] There are multiple factors that come into play. There's storm surge and tides. Tides around Morgan City are pretty modest (less than 1/2 foot / 15cm total range), and will be low as the storm arrives. Storm surge forcast is 7-11 ft per NOAA. Given the extreme low-lying land, that's significant. I don't have comparative numbers for Katrina offhand. The total rainfall amount is one. The period of time over which it falls, and where the storm goes afterward are also critical. Ida looks to be slow-moving, and is presently slated to track pretty much directly up the Mississippi river, then over the Ohio River Valley. That means there's going to be heavy river flow coming downstream possibly for several weeks after the storm itself passes. I'd predicted and observed a similar trend when Hurricane Florence hit Wilmington, NC, in 2018, and upstream-based water flows contributed to flooding, and issues such as hog farm sludge empoundments (basically: pig shit lakes) in the region. For Louisiana, the concern is probably more petroleum refining and chemical plants. Note that Florence hung around for days. Ida looks as if it will stick around Southern Louisiana for about 18 hours, then start accelerating to the NNE, though remaining over the drainage baisin feeding into New Orleans.

cryptoz 5y ago

I am collecting data on this storm using barometers in Android devices with All Clear Weather: https://play.google.com/store/apps/details?id=com.allclearweather.android https://play.google.com/store/apps/details?id=com.allclearwe... If you want to join, you can download the app and go to Settings->Sensors to enable. Here's an animation I made of Hurricane Dorian a couple years ago as it approached the coast of Florida: https://www.allclearweather.com/hurricane-dorian https://www.allclearweather.com/hurricane-dorian And of course, there are recent scientific papers showing that this kind of data (barometric pressure from phones) could be useful in general weather forecasting to improve accuracy: Smartphone Pressure Collection and Bias Correction Using Machine Learning: https://journals.ametsoc.org/doi/full/10.1175/JTECH-D-17-0096.1 https://journals.ametsoc.org/doi/full/10.1175/JTECH-D-17-009... Impacts of Assimilating Smartphone Pressure Observations on Forecast Skill during Two Case Studies in the Pacific Northwest: https://journals.ametsoc.org/doi/full/10.1175/WAF-D-18-0085.1 https://journals.ametsoc.org/doi/full/10.1175/WAF-D-18-0085....

meepmorp 5y ago

Look at a fancy view of the current forecast and other data here: https://cwcgom.aoml.noaa.gov/cgom/OceanViewer/index_phod.html https://cwcgom.aoml.noaa.gov/cgom/OceanViewer/index_phod.htm... edit: the sea surface temps are nuts

consumer451 5y ago
> the sea surface temps are nuts Can you imagine what these temps will look like if the Gulf Stream slows/shuts downs as predicted?
michaelbuckbee 5y ago
Can you expand on that a bit, I don't have any context to understand how far out of whack it is?
- baq 5y ago
  It’s a almost as bad as it could be. The only thing that could make this worse is of the hurricane slowed down over the gulf and stayed there for a couple days.
lnwlebjel 5y ago
Wow, hadn't seen this before. Thanks for posting it.
cjdaly 5y ago
here is a satellite view I've been watching, also from NOAA: https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=gm&band=GEOCOLOR&length=150 https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G1...
- fuzzfactor 5y ago
  That's the geostationary view of the gulf. Here's the "floater" that stays overhead of the storm as it comes ashore: https://www.star.nesdis.noaa.gov/goes/floater.php?stormid=AL092021 https://www.star.nesdis.noaa.gov/goes/floater.php?stormid=AL...

Karupan 5y ago

Genuine question since I don’t live in a city which experiences severe weather events annually: what is the financial incentive in rebuilding destroyed homes, businesses and other infrastructure every few years? Does that actually lead to a net positive outcome for those affected in the long run?

dghlsakjg 5y ago
Most of the time it isn't the same places that get hit. Its not as if the same neighborhood is rebuilt year after year, many of these places have homes and infrastructure that is 100 years old. Also keep in mind that a majority of the East Coast is under threat from Hurricanes. If we just abandoned any area that has been severely damaged by a hurricane, there would effectively be an unpopulated coastline from Boston to the Mexican border.
- acdha 5y ago
  There are steps between doing nothing and abandoning the east coast. There are some areas (right at sea level, river flood zones) which probably are better off as parks, and letting things like costal mangrove forests regrow would be important, but there’s a lot of places where a significant fraction of the existing buildings could remain viable if they were sensibly built following good design practice rather than as cheaply as the developers could get away with. It seems like something flood insurance and building codes should get increasingly stringent about, similar to how some California fire codes started requiring houses to be built to support sheltering in place during wildfires so you didn’t have so many people evacuating and needing to rebuild as many homes. It’d be nice if that started as guaranteed annual premium increases for unsafe properties with an assistance program for primary residences which phases out based on property value.
nolaspring 5y ago
Moral hazard has entered the chat.
- dredmorbius 5y ago

cos2pi 5y ago

For the interested, real-time data from the ongoing aircraft reconnaissance into (now) Hurricane Ida can be seen at https://www.tropicaltidbits.com/recon https://www.tropicaltidbits.com/recon

baq 5y ago
tropicaltisbits.com also hosts the author’s blog which is well worth following when major storms are present near the GOM.

claaams 5y ago

Good thing southern hospitals have a lot of space for casualties right now.. .

dredmorbius 5y ago
https://www.worldometers.info/coronavirus/usa/louisiana/ https://www.worldometers.info/coronavirus/usa/louisiana/ https://www.nytimes.com/interactive/2021/us/louisiana-covid-cases.html https://www.nytimes.com/interactive/2021/us/louisiana-covid-... 2,600 hospitalisations presently.
cmpb 5y ago
Yeah it is potentially a really bad situation right now in Louisiana. We have been getting our vax numbers up recently and the hospitalizations have started to come down in the past week or so, but not by much. With catastrophic hurricanes, though, what I've noticed is that we have lots of refugees (and deaths, in the case of Katrina) compared to hospitalizations. New Orleans can also turn the large arena areas (e.g. Superdome, Zephyr Field) into mass casualty and refugee areas immediately following the storm, which should help with keeping the hospitals from getting overrun.
- dredmorbius 5y ago
  The problem with refugees is crowding, displacement, lack of resources, and lack of communications. These tend to exacerbate any extant public health situations. Given general incompetence concerning Covid in the Southern US generally, I've certain concerns. What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota, then radiated outwards, toward the coasts and south, over the course of the winter, peaking around 10 Januare 2021. I've speculated that mass events, travel, return to school, and greater indoor activity (heating season in the north, as opposed to cooling season in the south) also contributed. This year the US might se a dual hotspot originating in Sturgis and Louisiana, both radiating outward. Something to keep tabs on.
  - jdminhbg 5y ago
    > What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota Is there any actual evidence for this?

dredmorbius 5y ago

I've been following the storm via Nullschool and its forecast model (GFS). Landfall of the eye has shifted about 40km westward, been delayed by about 6+ hours relative to the forecast 18 hours ago, and increased in intensity. The green circle here represents where the eyewall landfall was previously forecast to occur at about noon CST. Current forecast shows landfall at Jack Stout Bay, south of Morgan City, and tracking about 40km west of New Orleans proper. The area of landfall has been hit by several storms in the past several years, is mostly smaller settlements, and there are probably numerous already-damaged or only partially-repaired structures. https://earth.nullschool.net/#2021/08/29/1700Z/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-90.45,28.89,5202/loc=-90.074,29.475 https://earth.nullschool.net/#2021/08/29/1700Z/wind/surface/...

AdamN 5y ago
The problem is that the eye is not the most damaging part, it's the right side of the eye that's funneling water from the Gulf onto the land that's got the most damage potential. From that link it looks like New Orleans is in a much worse situation than if it were to receive a direct hit.
- dredmorbius 5y ago
  There's that. A near-westward hit could be more damaging than a direct strike, largely based on storm surge and possibly wind speeds. What the maximal high-damage offset distance is I don't know, though 20--40km seems sufficiently close to be bad. I'd suspect a little nearer would be worse. And I do wonder just how many more storms Nawlins and the Old River Structure have in them.
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dls2016 5y ago
Whoa! This site is rad! I often thought about making something like this. It always seems like the for-pay weather apps are crap but all the data is freely available.

b8 5y ago

I live in Louisiana, and attended Tulane for a while. Some streets around Tulane floods after a few hours of rain. I hope that every who lives in NOLA or high risk areas just goes ahead and leaves for right now. Some people tried to stay and party during Katrina. Hopefully folks don't make the same mistake twice...

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MisterBastahrd 5y ago

There's nothing to be happy about when a hurricane is bearing down on you, and it's worse when you're caught on the east side of the storm with heavy rains because the winds blow counter clockwise, meaning that rivers and streams and lakes that open or drain into the Gulf of Mexico will pile up and keep getting higher as long as the story is over the area. Southeast Louisiana can take 20 inches of rain over a few days, but not when there's no place for the water to go.

Fordec 5y ago

Louisiana is just going to lose so much territory between now and the end of the century to the ocean. Their shorelines are just too shallow to deal with the hurricanes and rising sea levels that are coming.

dredmorbius 5y ago
A pretty good chunk of what's mapped as land in Louisiana isn't. The map lies. https://medium.com/matter/louisiana-loses-its-boot-b55b3bd52d1e https://medium.com/matter/louisiana-loses-its-boot-b55b3bd52... http://samuel-warde.com/2018/10/louisiana-maps-are-all-a-lie-the-true-map-is-frightening/ http://samuel-warde.com/2018/10/louisiana-maps-are-all-a-lie... https://www.businessinsider.com/real-map-louisiana-should-scare-you-2017-6?op=1 https://www.businessinsider.com/real-map-louisiana-should-sc... https://yewtu.be/watch?v=ZBGYb5An8Mo https://yewtu.be/watch?v=ZBGYb5An8Mo

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WaltPurvis 5y ago

The National Hurricane Center has updated the forecast for Ida and now calls for it to be a 140 MPH Cat 4 (or greater) at landfall. The previous forecast had Ida topping out as a 120 MPH Cat 3. Storm surge of 10 to 15 feet above ground level will impact a broad area. https://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/271449.shtml https://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/271449...

selimthegrim 5y ago
Well I hope the trucker motels in West Memphis aren't full.