11/4/2024 4 PM – The National Hurricane Center’s (NHC) 4 PM update indicates that tropical depression 18 has gained tropical storm strength and will be named Rafael. The report also indicates that Rafael, presently located in the south central Caribbean would likely move over:
Jamaica late Monday night as a tropical storm
The Cayman Islands by Tuesday as a hurricane
Cuba on Wednesday as a hurricane
The Gulf of Mexico, heading north as a hurricane.
Rafael in center left at 3:40 CSTon 11/4/24
45 MPH Winds at 4PM and Strengthening
As of 4PM today, maximum sustained winds have increased to near 45 mph with higher gusts. NHC predicts steady-to-rapid strengthening. The system should become a hurricane on Tuesday.
NHC predicts Rafael will drop 3-6 inches of rain with amounts up to 9 inches locally over The Caymans, Jamaica and Cuba. That much will cause flooding and mudslides, they say.
Storm surge in the Caribbean will be 6-9 feet above normal tide levels. Swells generated by the system should affect much of the western Caribbean during the next few days. These swells will likely cause life-threatening surf and rip current conditions.
Models give the storm a 40 percent chance of a 30 kt speed increase in the next 24 hours and a near 50 percent chance of a 55 kt increase in 48 hours.
Track Over Caribbean Highly Uncertain At This Point
Models closely agree on the track of the storm while in the Caribbean but disagree where it will go once it enters the Gulf. There, model solutions diverge. NHC has low confidence in the Gulf of Mexico forecast track. The wide cone currently stretches from Houston to the Florida Panhandle.
The likely wind field will stretch even wider.
If the storm heads toward Houston, the leading edge of the winds could be felt as early as Friday morning.
Likely to Weaken in Gulf
Environmental factors of low wind shear, high moisture, and warm sea-surface temperatures support intensification. And since the system now has a well organized circulation, NHC has increasing confidence of steady strengthening until the system reaches Cuba or the southeastern Gulf of Mexico.
In 3 or 4 days, when the system reaches the central Gulf, a sharp increase in southwesterly vertical wind shear, drier air, and slightly cooler waters should end the strengthening trend and induce weakening.
Jeff Lindner, Harris County’s meteorologist predicts the system’s broad wind field will likely begin to impose along the upper Texas coast by late this week into the weekend. He also predicts that upper level wind shear over the US Gulf coast will likely greatly weaken any tropical system prior to reaching the US coast.
Regardless, check the NHC site often for recent updates and confidence about the track increases.
If Rafael is the last named storm of the season, it would put the total (18) in the range of NHC’s predictions.
Season Now Within Range of Earlier Predictions
Tropical events are rare in the Gulf this time of year but not unheard of. NHC’s climatology page shows many storms starting in the Caribbean during this 10-day period. A subset of those moves into the Gulf while others spin off into the Atlantic.
NHC predicted an above average number of named storms this year. Rafael, at number 18, puts us within the range they predicted.
Eighteen is also above the average number of named storms we receive in a season.
Posted by Bob Rehak on 11/4/24
2624 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/11/Rafael.jpg?fit=1000%2C680&ssl=16801000adminadmin2024-11-04 16:07:582024-11-04 16:07:59Tropical Storm Raphael Heading North
11/3/24 – The latest round of repairs to the understructure of the Tree Lane Bridge in Kingwood has been completed.
In recent years, flooding, erosion from severe storms, stream migration, and insufficiently mitigated upstream development had jeopardized the integrity of the bridge next to Bear Branch Elementary. Approximately 600 children attend Grades K through 5 at the school and dozens of school buses routinely cross over the bridge every school day.
Before Photos
The four pictures below show the starting point.
Imelda flood almost overtopped the bridgeand backed water up.Photo by Chris Bloch.Looking upstream at downstream side of the bridge. Water pressure created a jetting effect that undermined the support structure and eroded the area downstream. Downcutting exposed water line and utility cable.Closer shot shows the power of moving water. Storm drain outfall (right) was pinched off by debristhat broke away.Stormwater had also eaten away the concrete bed that tied supports together.
After Photos
Compare the next five shots taken on 11/3/24.
Upstream is left. Note how stream meander over time has Bens Branch approaching the bridge from a 45 degree angle now.
Meandering streams can impact bridges in a number of ways, including:
Altering flow characteristics: A meander at the upstream of a bridge can change the flow characteristics at the bridge’s inlet and outlet.
Reducing bridge capacity: A meander can reduce the amount of water a bridge can pass during a flood.
Creating channel instability: Channel instability near a bridge can increase the risk of bridge failure during a hydrologic event.
Meandering streams are characterized by their sinuous, snake-like channels. Meanders move sideways and downstream over time, which can create challenges for maintaining bridges and roads.
However, these repairs should improve safety …. at least for a while.
Looking upstream. Note new storm drain outfalls surrounded by concrete on the left and right.Note how the side slopes change from 45º to 90º about three feet above the bottom of the channel.
The stream bed was previously at where the wall angle changes. The area between the 90º walls represents additional carrying capacity (conveyance) for the channel under the bridge.
Also note, in the picture above, the addition of at least five new rounded piers to increase support for the bridge’s road bed. The old piers are square.
Storm sewer outfall is now at an angle. Same on the opposite side.
According to ChatGPT, “Storm sewer outfalls are often angled when they enter a stream to help manage the flow of water and sediment, reduce erosion, and improve the overall stability of the stream bank.”
Also note in this shot by Chris Bloch how contractors hydromulched slopes and areas disturbed by construction.
Hydromulching should reduce erosion from water flowing over the top of the channel bank.
Thanks to Houston Public Works and the City of Houston for these repairs. I’ll check to see how these improvements work in future storms.
For More Information
For a history of the project and to see additional photos, see these previous posts:
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/11/20241103-DJI_20241103083715_0140_D.jpg?fit=1100%2C619&ssl=16191100adminadmin2024-11-03 12:06:442024-11-03 18:09:57Before-After Pics of 2024 Tree Lane Bridge Repairs
11/2/24 – Numerous academic studies have found an increase in the number of storms with decreasing forward speeds, i.e., tropical cyclone stalling, when comparing recent decades with earlier periods.
Meteorologists call the distance that tropical cyclones travel in a given amount of time “tropical cyclone translation speed” or TCTS.
They have also found that TCTS is a key factor in determining the damage a tropical cyclone can cause to a community from rainfall, exposure to high winds, flooding and storm surge. That damage totals more than a trillion dollars in the last 40 years with death tolls in the thousands.
There is broad academic agreement on the increase in the number of slow-moving or stalling storms. And they identify the central Gulf Coast as one of the hot spots.
Some studies have also found a correlation between stalling storms and rapid intensification near coastlines, a red flag for emergency managers.
She says that regions experiencing tropical cyclones “will experience greater exposure to some of the most devastating aspects of tropical cyclones such as extreme rainfall, wind speeds, and flooding. Increased exposure to these elements could and will likely translate to a rise in both economic devastation and fatalities.”
21% decrease over land areas in the western North Pacific
16% decrease over land areas affected by North Atlantic tropical cyclones
22% decrease over land areas in the Australian region.
Remember, the more time a storm lingers over any given area, the higher the rainfall accumulations.
Hurricane Harvey a Notable Example
Kossin also notes that “unprecedented rainfall totals associated with the ‘stall’ of Hurricane Harvey13,14,15 over Texas in 2017 provide a notable example of the relationship between regional rainfall amounts and tropical-cyclone translation speed.”
Hurricane Harvey as it approached the Texas coast in 2017
Kossin concluded that the “translation speed of tropical cyclones, particularly over land, is therefore highly relevant when considering potential changes in local rainfall totals.”
The authors found that TCTS influences rainfall accumulation, storm surge, and exposure to high winds. These effects are greatest when storms stall.
Trepanier and her colleagues provide both a definition and climatology of slow-moving or stalling TCs in the North Atlantic from 1900–2020. “A stall is defined as a tropical cyclone (TC) with a track contained in a circular area … with a radius of ≤ 200 km for 72 hours.”
The authors found that of 1,274 North Atlantic tropical cyclones, 191 or 15% met this definition. Of those, 10 stalled more than once. Hurricane Ginger in 1971 stalled the most with four separate stalls.
“Stalling TC locations are clustered in the western Caribbean, the central Gulf Coast, the Bay of Campeche, and near Florida and the Carolinas,” say the authors. “Stalling was most common in October TCs (17.3% of October total) and least common in August (8.2%).”
Their study examined two time periods, 1900-2020 and 1966-2020, and statistically tested for trends in the annual frequency of stalling storms.
The estimated annual frequency of stalls significantly increased from 1966–2020 by 1.5% per year. The cumulative frequency in the number of stalls compared to all storms also increased.
“Stalling storms have a significantly higher frequency of major hurricane status than non-stalling storms. Storms are also more likely to stall near the coast (≤ 200 km). Approximately 40% (n=77) of the stalling TCs experienced a period of rapid intensification, and five did so within 200 km of a coastal zone.”
The authors believe their findings will help emergency managers better prepare for the future. Speaking of that…
Stay Alert
Remember that hurricane season isn’t over until the end of November. The National Hurricane center shows three areas of activity in the Atlantic. They’re giving the closest one in the southwestern Caribbean an 80% chance of formation in the next seven days.
Don’t let your guard down yet.
Posted by Bob Rehak on 11/2/24
2622 Days since Hurricane Harvey
*Extensive quotes from abstract reproduced with permission of copyright holder.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/08/Harvey-Peak-Intensity.jpg?fit=1500%2C843&ssl=18431500adminadmin2024-11-02 12:27:302024-11-02 13:57:27Impacts of Tropical Cyclone Stalling
Tropical Storm Raphael Heading North
11/4/2024 4 PM – The National Hurricane Center’s (NHC) 4 PM update indicates that tropical depression 18 has gained tropical storm strength and will be named Rafael. The report also indicates that Rafael, presently located in the south central Caribbean would likely move over:
45 MPH Winds at 4PM and Strengthening
As of 4PM today, maximum sustained winds have increased to near 45 mph with higher gusts. NHC predicts steady-to-rapid strengthening. The system should become a hurricane on Tuesday.
NHC predicts Rafael will drop 3-6 inches of rain with amounts up to 9 inches locally over The Caymans, Jamaica and Cuba. That much will cause flooding and mudslides, they say.
Storm surge in the Caribbean will be 6-9 feet above normal tide levels. Swells generated by the system should affect much of the western Caribbean during the next few days. These swells will likely cause life-threatening surf and rip current conditions.
Models give the storm a 40 percent chance of a 30 kt speed increase in the next 24 hours and a near 50 percent chance of a 55 kt increase in 48 hours.
Track Over Caribbean Highly Uncertain At This Point
Models closely agree on the track of the storm while in the Caribbean but disagree where it will go once it enters the Gulf. There, model solutions diverge. NHC has low confidence in the Gulf of Mexico forecast track. The wide cone currently stretches from Houston to the Florida Panhandle.
The likely wind field will stretch even wider.
If the storm heads toward Houston, the leading edge of the winds could be felt as early as Friday morning.
Likely to Weaken in Gulf
Environmental factors of low wind shear, high moisture, and warm sea-surface temperatures support intensification. And since the system now has a well organized circulation, NHC has increasing confidence of steady strengthening until the system reaches Cuba or the southeastern Gulf of Mexico.
In 3 or 4 days, when the system reaches the central Gulf, a sharp increase in southwesterly vertical wind shear, drier air, and slightly cooler waters should end the strengthening trend and induce weakening.
Jeff Lindner, Harris County’s meteorologist predicts the system’s broad wind field will likely begin to impose along the upper Texas coast by late this week into the weekend. He also predicts that upper level wind shear over the US Gulf coast will likely greatly weaken any tropical system prior to reaching the US coast.
Regardless, check the NHC site often for recent updates and confidence about the track increases.
If Rafael is the last named storm of the season, it would put the total (18) in the range of NHC’s predictions.
Season Now Within Range of Earlier Predictions
Tropical events are rare in the Gulf this time of year but not unheard of. NHC’s climatology page shows many storms starting in the Caribbean during this 10-day period. A subset of those moves into the Gulf while others spin off into the Atlantic.
NHC predicted an above average number of named storms this year. Rafael, at number 18, puts us within the range they predicted.
Eighteen is also above the average number of named storms we receive in a season.
Posted by Bob Rehak on 11/4/24
2624 Days since Hurricane Harvey
Before-After Pics of 2024 Tree Lane Bridge Repairs
11/3/24 – The latest round of repairs to the understructure of the Tree Lane Bridge in Kingwood has been completed.
In recent years, flooding, erosion from severe storms, stream migration, and insufficiently mitigated upstream development had jeopardized the integrity of the bridge next to Bear Branch Elementary. Approximately 600 children attend Grades K through 5 at the school and dozens of school buses routinely cross over the bridge every school day.
Before Photos
The four pictures below show the starting point.
After Photos
Compare the next five shots taken on 11/3/24.
Meandering streams can impact bridges in a number of ways, including:
Meandering streams are characterized by their sinuous, snake-like channels. Meanders move sideways and downstream over time, which can create challenges for maintaining bridges and roads.
However, these repairs should improve safety …. at least for a while.
The stream bed was previously at where the wall angle changes. The area between the 90º walls represents additional carrying capacity (conveyance) for the channel under the bridge.
Also note, in the picture above, the addition of at least five new rounded piers to increase support for the bridge’s road bed. The old piers are square.
According to ChatGPT, “Storm sewer outfalls are often angled when they enter a stream to help manage the flow of water and sediment, reduce erosion, and improve the overall stability of the stream bank.”
Also note in this shot by Chris Bloch how contractors hydromulched slopes and areas disturbed by construction.
Hydromulching should reduce erosion from water flowing over the top of the channel bank.
Thanks to Houston Public Works and the City of Houston for these repairs. I’ll check to see how these improvements work in future storms.
For More Information
For a history of the project and to see additional photos, see these previous posts:
10/12/24 Tree Lane Bridge Repairs Nearing Completion
8/11/24 Tree Lane Bridge Repairs Finally Starting Again, Hopefully for Last Time
6/28/24 Tree Lane Project Supposed to be Done Today, But Hasn’t Started
4/9/24 City Begins Tree Lane Bridge Repairs
2/21/24 CoH Public Works Kicks Off Tree Lane Bridge Rehab Project
11/28/23 Tree Lane Bridge over Bens Branch Still Standing
6/12/23 Flood Damage To Tree Lane Bridge Over Ben’s Branch Accelerates
1/29/23 Tree Lane Bridge over Ben’s Branch Damaged…Again
3/21/22 How Insufficiently Mitigated Upstream Development Imposes Taxation without Representation on Downstream Residents
3/31/20 City Completes Repairs on Tree Lane Bridge, But Concerns Remain
2/29/20 Tree Lane Bridge over Ben’s Branch: Before and After Repairs
12/2/19 Tree Lane Bridge vs. Power of Moving Water
Posted by Bob Rehak on 11/3/24
2623 Days since Hurricane Harvey
Impacts of Tropical Cyclone Stalling
11/2/24 – Numerous academic studies have found an increase in the number of storms with decreasing forward speeds, i.e., tropical cyclone stalling, when comparing recent decades with earlier periods.
Meteorologists call the distance that tropical cyclones travel in a given amount of time “tropical cyclone translation speed” or TCTS.
They have also found that TCTS is a key factor in determining the damage a tropical cyclone can cause to a community from rainfall, exposure to high winds, flooding and storm surge. That damage totals more than a trillion dollars in the last 40 years with death tolls in the thousands.
There is broad academic agreement on the increase in the number of slow-moving or stalling storms. And they identify the central Gulf Coast as one of the hot spots.
Some studies have also found a correlation between stalling storms and rapid intensification near coastlines, a red flag for emergency managers.
Rise in Economic Devastation and Fatalities
Marybeth Melcher of Western Michigan University published “Tropical Cyclone Translation Speeds in the Northern Atlantic Ocean.” She found statistically significant trends indicating an increase in the duration of cyclones (slowing of forward motion) over forty-years.
She says that regions experiencing tropical cyclones “will experience greater exposure to some of the most devastating aspects of tropical cyclones such as extreme rainfall, wind speeds, and flooding. Increased exposure to these elements could and will likely translate to a rise in both economic devastation and fatalities.”
Slowdown Found to Be Global
In a 2018 study called “A global slowdown of tropical-cyclone translation speed” published in Nature, James P. Kossin found that TCTS has decreased globally by 10% from 1949–2016. That includes a:
Remember, the more time a storm lingers over any given area, the higher the rainfall accumulations.
Hurricane Harvey a Notable Example
Kossin also notes that “unprecedented rainfall totals associated with the ‘stall’ of Hurricane Harvey13,14,15 over Texas in 2017 provide a notable example of the relationship between regional rainfall amounts and tropical-cyclone translation speed.”
Kossin concluded that the “translation speed of tropical cyclones, particularly over land, is therefore highly relevant when considering potential changes in local rainfall totals.”
Recent Study Focused on Atlantic Basin
In September of 2024, Dr. Jill C. Trepanier, Dr. John Nielsen-Gammon, Dr. Vincent M. Brown, Derek T. Thompson, and Dr. Barry D. Keim published “Stalling North Atlantic Tropical Cyclones” in the Journal of Applied Meteorology and Climatology (© 2024 American Meteorological Society*.)
The authors found that TCTS influences rainfall accumulation, storm surge, and exposure to high winds. These effects are greatest when storms stall.
Trepanier and her colleagues provide both a definition and climatology of slow-moving or stalling TCs in the North Atlantic from 1900–2020. “A stall is defined as a tropical cyclone (TC) with a track contained in a circular area … with a radius of ≤ 200 km for 72 hours.”
The authors found that of 1,274 North Atlantic tropical cyclones, 191 or 15% met this definition. Of those, 10 stalled more than once. Hurricane Ginger in 1971 stalled the most with four separate stalls.
“Stalling TC locations are clustered in the western Caribbean, the central Gulf Coast, the Bay of Campeche, and near Florida and the Carolinas,” say the authors. “Stalling was most common in October TCs (17.3% of October total) and least common in August (8.2%).”
Their study examined two time periods, 1900-2020 and 1966-2020, and statistically tested for trends in the annual frequency of stalling storms.
The estimated annual frequency of stalls significantly increased from 1966–2020 by 1.5% per year. The cumulative frequency in the number of stalls compared to all storms also increased.
“Stalling storms have a significantly higher frequency of major hurricane status than non-stalling storms. Storms are also more likely to stall near the coast (≤ 200 km). Approximately 40% (n=77) of the stalling TCs experienced a period of rapid intensification, and five did so within 200 km of a coastal zone.”
The authors believe their findings will help emergency managers better prepare for the future. Speaking of that…
Stay Alert
Remember that hurricane season isn’t over until the end of November. The National Hurricane center shows three areas of activity in the Atlantic. They’re giving the closest one in the southwestern Caribbean an 80% chance of formation in the next seven days.
Don’t let your guard down yet.
Posted by Bob Rehak on 11/2/24
2622 Days since Hurricane Harvey
*Extensive quotes from abstract reproduced with permission of copyright holder.