9/8/26 – At 4 am CDT today, the National Hurricane Center (NHC) issued an advisory stating that Tropical Storm Isaias had intensified into a hurricane overnight. NHC expects winds to increase to near major hurricane status in the next 24 hours and says the storm will produce life-threatening surge up to 7-feet high across the northern Gulf Coast from the mouth of the Mississippi to the Florida panhandle.
Isaias is now moving toward the east-northeast near 9 mph and should turn toward the northeast later today followed by a turn northward on Friday. NHC expects landfall along the U.S. northern Gulf Coast late Friday or early Saturday.
A dropsonde launched from an Air Force Reserve hurricane hunter found average winds of 76 kt – the basis for upgrading Isaias to a hurricane at 0330 UTC.
Environmental Factors Affecting Forecast
Since that time, Isaias has continued to intensify, but with some northward tilt with height, likely due to moderate westerly vertical wind shear that continues to hinder circulation. However, circulation has increased since yesterday.
Aircraft fixes indicate that Isaias continues to maintain an east-northeastward heading. The most critical steering features:
A subtropical ridge centered east of the Bahamas
A mid-level trough along the northern Gulf coast
Low pressure digging in from the Rocky Mountains.
The net effect:
Isaias should make a left turn to the northeast and the north over the next 24-48 hours.
NHC
The forecast has not changed appreciably though models continue to disagree over the exact track (east or west) after the turn to the north. The storm should become post-tropical over the Tennessee Valley.
The intensity forecast remains difficult. Isaias is fighting around 20 kt of westerly vertical wind shear, and an eyewall keeps coming and going.
Infrared image of circulation at 5 AM CDT
Other favorable environmental factors for further intensification include 30 C sea-surface temperatures and abundant moisture. Shear should not increase appreciably for the next 24 hours. In fact, the hurricane has intensified despite shear. So NHC expects significant intensification in the short-term. making Isaias just shy of major hurricane intensity in 24 hours.
However, in the final 12-24 hours before Isaias makes landfall on the north Gulf coast, vertical wind shear should ramp up to 40-50 kt. This will likely impart some weakening. At the same time, the hurricane’s wind field may become broader.
Regardless, NHC expects Isaias to remain a dangerous hurricane through landfall with gusty winds extended well inland.
Key Messages from NHC
Key Messages:
1. Isaias should strengthen and become a strong hurricane when it approaches the northern Gulf Coast on Friday. A life-threatening storm surge is expected along a portion of the northern Gulf Coast,and a Storm Surge Warning remains in effect from the Mouth of the Mississippi River to Steinhatchee, Florida. Residents in the warning area should follow advice given by local officials and evacuate if told to do so.
2. Damaging hurricane force-winds will extend across the Florida Panhandle, southern Alabama, and southern Mississippi. A Hurricane Warning remains in effect from Ocean Springs, Mississippi to the Bay/Gulf County Line, Florida. Residents there should prepare for extended power outages.
3. Isaias will bring areas of heavy rainfall to the central U.S. Gulf coast and much of the Southeast Friday into the weekend. Flash and urban flooding, along with isolated river flooding, will be possible.
NHC Graphics Illustrate Risks
The graphics below show current predicted risks.
Isaias track forecastRainfall forecastIsaias flash-flood risk Isaias wind field
Isaias is the latest “first hurricane of the Atlantic season” on record.
Posted by Bob Rehak on 9/8/2026 based on NHC information
3327 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2026/10/Isaias-9.8.26-5am.jpg?fit=1000%2C1000&ssl=110001000adminadmin2026-10-08 05:57:092026-10-08 05:57:10Isaias Now a Hurricane
10/6/2026 – At 1 pm, the National Hurricane Center (NHC) gave a 100% chance of tropical formation in the Bay of Campeche near the Yucatan Peninsula, up from 90% earlier this morning.
Some weather models suggest it could become as strong as a Category 4, though most suggest a lower intensity level. Three models put it into the “major storm” category.
High pressure in Texas will likely protect the Houston region and push the storm toward Louisiana and the Florida Panhandle. You can see the effect of the high pressure below.
Satellite image from NHC as of 9:51 Houston time on 10/6/26
This animated loop on Tropical Tidbits shows the storm growing and the beginnings of an eye, which is also visible on the water vapor image below.
Water vapor image from 9:46am Houston time on 9/6/26
Timing and Impacts
We should see strengthening later this week.
Regardless of intensity, heavy rains and flooding could occur over portions of the northern Gulf coast and southeastern U.S. later this week and into the weekend.
According to Jeff Lindner, Harris County’s meteorologist, Invest 92L looks better organized this morning, but it’s difficult to tell whether a center of circulation has formed yet. The system is drifting toward the east or southeast and this general motion should continue for the next day or so.
Lindner says lower pressure will develop over west Texas later this week allowing the storm to turn north and accelerate. The system should drift for the next 24 hours before starting a more consistent motion around 48 hours, and then a faster northward motion later this week.
“On this track, a hurricane will likely approach the central U.S. Gulf coast late this week or early this weekend.”
Jeff Lindner, Harris County Meteorologist
Persistent northeasterly flow along the coast will increase into late week. Forecasted tides will run 1-2 feet above normal by late week and minor coastal flooding will be possible at times of high tide from Thursday through Saturday. Depending on the intensity of 92L, higher swells could push tides a bit higher than currently forecast.
No single authority in the San Jacinto River Basin has responsibility for flooding. Instead we have jurisdictional fragmentation. Multiple jurisdictions have limited authority to solve parts of our regional flooding problems.
The Plan states, “Many of these entities have the authority to implement flood-related planning or projects but do not necessarily have the authority to implement or enforce floodplain management practices or standards.”
Collectively, our governmental organizations don’t match the nature of the problem: floodwater doesn’t respect jurisdictional boundaries. Yet people don’t want to give up their limited authority.
Local control doesn’t yield a collective solution.
Scarborough Example
The Scarborough Development in southern Montgomery County at the confluence of Spring and Cypress Creeks with the San Jacinto West Fork exemplifies the regulatory issue. Scarborough’s 5,300 acres lie between multiple jurisdictions.
The proposed development is in Montgomery County but borders Harris County. Part of it is in Houston’s extra territorial jurisdiction (ETJ) and part isn’t.
FEMA has updated its flood maps only for portions of the proposed development that lie within Houston’s ETJ.
The development lies in Montgomery County Precinct 3 but will affect flooding in Precinct 4 and Harris County.
Montgomery County doesn’t have a flood control district. Harris County does.
Subsidence plagues the area and development will make subsidence worse. That could create a bowl in the landscape that increases flood risk. But the Lone Star Groundwater Conservation District is not considering subsidence in its new plans and will not acknowledge the concerns of the Harris-Galvestion Subsidence District.
Almost all of the proposed development lies in a floodplain or floodway. See below.
Only dark gray areas within red border are elevated above floodplains.US59 bridge during Harvey at intersection of Montgomery and Harris Counties, Houston and Humble; Scarborough just out of frame to right.
San Jacinto Regional Flood Planning Group Recommendations
To solve this problem and others like it, the San Jacinto Regional Flood Planning group is considering a series of legislative and regulatory recommendations that include:
Creating, consolidating, or reorganizing regional flood authorities, flood-control districts, river authority programs, and drainage districts where broader regional coordination is needed.
Clarifying roles and responsibilities for floodplain management in extraterritorial jurisdiction (ETJ) areas to reduce gaps or overlaps in responsibility for floodplain management, permitting, and drainage standards..
Three Aspects of Current, Self-Defeating “Flood Governance”
In business, management consultants commonly call this a “silo problem.” The more precise governance term is an “institutional collective-action dilemma,” compounded by a “scale mismatch.”
Organizational Silos
McKinsey describes how optimizing individual functions in silos can undermine performance when trying to address a collective concern. In this case, think of departments as jurisdictions and the San Jacinto River watershed as the organization.
Theoretically, the San Jacinto River Authority (SJRA) has responsibility to control flooding throughout the river basin. But the SJRA almost never exercises it; they say they don’t have funding. The closest they’ve come to flood management is when they established a flood management division after Hurricane Harvey. But they have only managed a series of studies funded by others. And the studies have produced no tangible improvements to date.
Because floodwaters don’t respect jurisdictional boundaries, independent authorities need a shared solution. However, disagreements over costs, benefits, commitments, and loss of autonomy impede collective action.
Political scientist Richard Feiock describes this as “an institutional collective-action dilemma.” The term explicitly addresses barriers to coordinated decisions, including negotiation costs, constraints on autonomy, and difficulty securing enforceable commitments. Cooperation can benefit the region while requiring individual governments to accept obligations or surrender some discretion.
Scale/Institutional Mismatch
The geographic reach of the flooding problem exceeds the geographic reach of the institutions empowered to address it.
The term “scale mismatch” captures this dilemma. Some water-governance researchers call this the problem of institutional fit: whether the institutions managing a resource match its physical processes and geographic extent. Academic research has applied this concept specifically to flood planning across jurisdictions.
Fragmented Flood Governance and Conflicting Mandates
In Texas, authority to address flooding issues does not match the geographic extent of watersheds. And local incentives do not necessarily produce river-basin-wide results. The problem is especially acute for those who live or work at the intersection of jurisdictional boundaries.
Yes, multiple authorities could achieve a collective solution through binding agreements, shared standards, funding, and accountability. But there is no effective mechanism for making local decisions serve basin-wide, flood-reduction concerns.
Worse, some of the jurisdictions that have responsibility to fix flooding also have conflicting mandates. For instance, Montgomery County Engineering, which would permit the Scarborough Development, answers to the County Judge and Commissioners. Their top priority may be economic growth.
Another example: The Texas General Land Office, which administers $14 billion of Flood Remediation and Mitigation money for the US Department of Housing and Urban Development, has reportedly invested $140 million in developing the Scarborough land – some of the most flood-prone land in the region.
Need for a River-Basin-Wide Flood-Control District
One in five Texans live in a known floodplain … and more than one in four in the San Jacinto River Basin (27%). Nationally, a commonly cited benchmark for people living in floodplains is 10%.
According to the 2024 State Flood Plan, 5.2 million Texans live or work in identified 100-year or 500-year flood-hazard areas. Those areas contain 1.66 million buildings. And those figures would likely grow if all floodplains were mapped using current rainfall statistics.
Clearly, the upcoming state legislature should seriously consider the San Jacinto Regional Flood Planning Group’s recommendations above to consolidate responsibilities for flood management.
Early voting starts this month. In the meantime, sign the petition protesting Scarborough if you haven’t already done so. One of the region’s most respected hydrologists has said that if the property gets developed, it would be like aiming a firehose at the Kingwood/Humble area.
Posted by Bob Rehak on 10/5/26
3324 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/10/Harvey-at-59-Bridge-IMG_3686-e1741129570215.jpeg?fit=1100%2C685&ssl=16851100adminadmin2026-10-05 15:14:362026-10-05 15:19:10Why 27% of People in the San Jacinto River Basin Live or Work in a Floodplain
Isaias Now a Hurricane
9/8/26 – At 4 am CDT today, the National Hurricane Center (NHC) issued an advisory stating that Tropical Storm Isaias had intensified into a hurricane overnight. NHC expects winds to increase to near major hurricane status in the next 24 hours and says the storm will produce life-threatening surge up to 7-feet high across the northern Gulf Coast from the mouth of the Mississippi to the Florida panhandle.
Isaias is now moving toward the east-northeast near 9 mph and should turn toward the northeast later today followed by a turn northward on Friday. NHC expects landfall along the U.S. northern Gulf Coast late Friday or early Saturday.
A dropsonde launched from an Air Force Reserve hurricane hunter found average winds of 76 kt – the basis for upgrading Isaias to a hurricane at 0330 UTC.
Environmental Factors Affecting Forecast
Since that time, Isaias has continued to intensify, but with some northward tilt with height, likely due to moderate westerly vertical wind shear that continues to hinder circulation. However, circulation has increased since yesterday.
Aircraft fixes indicate that Isaias continues to maintain an east-northeastward heading. The most critical steering features:
The net effect:
The forecast has not changed appreciably though models continue to disagree over the exact track (east or west) after the turn to the north. The storm should become post-tropical over the Tennessee Valley.
The intensity forecast remains difficult. Isaias is fighting around 20 kt of westerly vertical wind shear, and an eyewall keeps coming and going.
Other favorable environmental factors for further intensification include 30 C sea-surface temperatures and abundant moisture. Shear should not increase appreciably for the next 24 hours. In fact, the hurricane has intensified despite shear. So NHC expects significant intensification in the short-term. making Isaias just shy of major hurricane intensity in 24 hours.
However, in the final 12-24 hours before Isaias makes landfall on the north Gulf coast, vertical wind shear should ramp up to 40-50 kt. This will likely impart some weakening. At the same time, the hurricane’s wind field may become broader.
Regardless, NHC expects Isaias to remain a dangerous hurricane through landfall with gusty winds extended well inland.
Key Messages from NHC
Key Messages:
1. Isaias should strengthen and become a strong hurricane when it approaches the northern Gulf Coast on Friday. A life-threatening storm surge is expected along a portion of the northern Gulf Coast,and a Storm Surge Warning remains in effect from the Mouth of the Mississippi River to Steinhatchee, Florida. Residents in the warning area should follow advice given by local officials and evacuate if told to do so.
2. Damaging hurricane force-winds will extend across the Florida Panhandle, southern Alabama, and southern Mississippi. A Hurricane Warning remains in effect from Ocean Springs, Mississippi to the Bay/Gulf County Line, Florida. Residents there should prepare for extended power outages.
3. Isaias will bring areas of heavy rainfall to the central U.S. Gulf coast and much of the Southeast Friday into the weekend. Flash and urban flooding, along with isolated river flooding, will be possible.
NHC Graphics Illustrate Risks
The graphics below show current predicted risks.
Isaias is the latest “first hurricane of the Atlantic season” on record.
Posted by Bob Rehak on 9/8/2026 based on NHC information
3327 Days since Hurricane Harvey
Hurricane Likely in Gulf
10/6/2026 – At 1 pm, the National Hurricane Center (NHC) gave a 100% chance of tropical formation in the Bay of Campeche near the Yucatan Peninsula, up from 90% earlier this morning.
Some weather models suggest it could become as strong as a Category 4, though most suggest a lower intensity level. Three models put it into the “major storm” category.
High pressure in Texas will likely protect the Houston region and push the storm toward Louisiana and the Florida Panhandle. You can see the effect of the high pressure below.
This animated loop on Tropical Tidbits shows the storm growing and the beginnings of an eye, which is also visible on the water vapor image below.
Timing and Impacts
We should see strengthening later this week.
Regardless of intensity, heavy rains and flooding could occur over portions of the northern Gulf coast and southeastern U.S. later this week and into the weekend.
According to Jeff Lindner, Harris County’s meteorologist, Invest 92L looks better organized this morning, but it’s difficult to tell whether a center of circulation has formed yet. The system is drifting toward the east or southeast and this general motion should continue for the next day or so.
Lindner says lower pressure will develop over west Texas later this week allowing the storm to turn north and accelerate. The system should drift for the next 24 hours before starting a more consistent motion around 48 hours, and then a faster northward motion later this week.
Persistent northeasterly flow along the coast will increase into late week. Forecasted tides will run 1-2 feet above normal by late week and minor coastal flooding will be possible at times of high tide from Thursday through Saturday. Depending on the intensity of 92L, higher swells could push tides a bit higher than currently forecast.
Monitor the National Weather Service and National Hurricane Center for frequent updates as the storm approaches land.
As we saw with Tropical Storm Edouard, minor changes in the track of a storm can make huge differences in impacts. At this stage, nothing is certain.
Posted by Bob Rehak on 10/6/2026
3325 Days since Hurricane Harvey
Why 27% of People in the San Jacinto River Basin Live or Work in a Floodplain
No single authority in the San Jacinto River Basin has responsibility for flooding. Instead we have jurisdictional fragmentation. Multiple jurisdictions have limited authority to solve parts of our regional flooding problems.
The amended 2023 San Jacinto Regional Flood Plan (Page 1-13) indicates the river basin has:
The Plan states, “Many of these entities have the authority to implement flood-related planning or projects but do not necessarily have the authority to implement or enforce floodplain management practices or standards.”
Collectively, our governmental organizations don’t match the nature of the problem: floodwater doesn’t respect jurisdictional boundaries. Yet people don’t want to give up their limited authority.
Scarborough Example
The Scarborough Development in southern Montgomery County at the confluence of Spring and Cypress Creeks with the San Jacinto West Fork exemplifies the regulatory issue. Scarborough’s 5,300 acres lie between multiple jurisdictions.
Almost all of the proposed development lies in a floodplain or floodway. See below.
San Jacinto Regional Flood Planning Group Recommendations
To solve this problem and others like it, the San Jacinto Regional Flood Planning group is considering a series of legislative and regulatory recommendations that include:
Three Aspects of Current, Self-Defeating “Flood Governance”
In business, management consultants commonly call this a “silo problem.” The more precise governance term is an “institutional collective-action dilemma,” compounded by a “scale mismatch.”
Organizational Silos
McKinsey describes how optimizing individual functions in silos can undermine performance when trying to address a collective concern. In this case, think of departments as jurisdictions and the San Jacinto River watershed as the organization.
Theoretically, the San Jacinto River Authority (SJRA) has responsibility to control flooding throughout the river basin. But the SJRA almost never exercises it; they say they don’t have funding. The closest they’ve come to flood management is when they established a flood management division after Hurricane Harvey. But they have only managed a series of studies funded by others. And the studies have produced no tangible improvements to date.
So, by default, the watershed functions under multiple jurisdictions that each work within their own boundaries, responsibilities, budgets, and priorities. However, solving flooding problems requires collective action across jurisdictions.
Institutional Collective-Action Dilemma
Because floodwaters don’t respect jurisdictional boundaries, independent authorities need a shared solution. However, disagreements over costs, benefits, commitments, and loss of autonomy impede collective action.
Political scientist Richard Feiock describes this as “an institutional collective-action dilemma.” The term explicitly addresses barriers to coordinated decisions, including negotiation costs, constraints on autonomy, and difficulty securing enforceable commitments. Cooperation can benefit the region while requiring individual governments to accept obligations or surrender some discretion.
Scale/Institutional Mismatch
The geographic reach of the flooding problem exceeds the geographic reach of the institutions empowered to address it.
The term “scale mismatch” captures this dilemma. Some water-governance researchers call this the problem of institutional fit: whether the institutions managing a resource match its physical processes and geographic extent. Academic research has applied this concept specifically to flood planning across jurisdictions.
Fragmented Flood Governance and Conflicting Mandates
In Texas, authority to address flooding issues does not match the geographic extent of watersheds. And local incentives do not necessarily produce river-basin-wide results. The problem is especially acute for those who live or work at the intersection of jurisdictional boundaries.
Yes, multiple authorities could achieve a collective solution through binding agreements, shared standards, funding, and accountability. But there is no effective mechanism for making local decisions serve basin-wide, flood-reduction concerns.
Worse, some of the jurisdictions that have responsibility to fix flooding also have conflicting mandates. For instance, Montgomery County Engineering, which would permit the Scarborough Development, answers to the County Judge and Commissioners. Their top priority may be economic growth.
Another example: The Texas General Land Office, which administers $14 billion of Flood Remediation and Mitigation money for the US Department of Housing and Urban Development, has reportedly invested $140 million in developing the Scarborough land – some of the most flood-prone land in the region.
Need for a River-Basin-Wide Flood-Control District
One in five Texans live in a known floodplain … and more than one in four in the San Jacinto River Basin (27%). Nationally, a commonly cited benchmark for people living in floodplains is 10%.
According to the 2024 State Flood Plan, 5.2 million Texans live or work in identified 100-year or 500-year flood-hazard areas. Those areas contain 1.66 million buildings. And those figures would likely grow if all floodplains were mapped using current rainfall statistics.
Clearly, the upcoming state legislature should seriously consider the San Jacinto Regional Flood Planning Group’s recommendations above to consolidate responsibilities for flood management.
State Representative Dennis Paul proposed such legislation previously. But the parochial concerns of local authorities, such as Harris County Commissioner Adrian Garcia, fearful of losing influence and control, killed the bill.
Early voting starts this month. In the meantime, sign the petition protesting Scarborough if you haven’t already done so. One of the region’s most respected hydrologists has said that if the property gets developed, it would be like aiming a firehose at the Kingwood/Humble area.
Posted by Bob Rehak on 10/5/26
3324 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.