The National Weather Service has issued an urban and small stream advisory for the northern Lake Houston Area. It extends across north Houston up to Conroe. Expect street flooding.
According to Harris County meteorologist Jeff Lindner, the center of Imelda is drifting over southwest Montgomery County as of late Wednesday morning. Lindner adds that “lull” in heavy rainfall over Harris County should last until early afternoon. Expect rain to pick up significantly between mid afternoon and evening.
Flash Flooding Possible
The National Weather Service cautions that heavy downpours with rainfall rates between 2-4 inches per hour are possible. That’s enough to cause street flooding.
The National Weather Service in League City has issued a
* Urban and Small Stream Flood Advisory for...
Southwestern San Jacinto County in southeastern Texas...
Southeastern Montgomery County in southeastern Texas...
West central Liberty County in southeastern Texas...
Northeastern Harris County in southeastern Texas...
* Until 1245 PM CDT.
* At 949 AM CDT, Doppler radar indicated heavy rain that will cause
urban and small stream flooding in the advisory area. 3 to 6
inches of rain have already fallen across portions of these areas
and additional rain is expected during the next several hours.
* Some locations that will experience flooding include...
Conroe, Humble, Jersey Village, Willis, Aldine, Northside /
Northline, Kingwood, The Woodlands, Greater Greenspoint, Spring,
Spring Branch North, northeastern Addicks Park Ten, Oak Ridge
North, Panorama Village, Shenandoah, Splendora, Patton Village,
Roman Forest, Woodbranch and Cut And Shoot.
Incredible Rainfall Rates South of Houston
Incredible rainfall rates of 3-4 inches per hour have resulted in a 24 hour storm total of 21.34 inches at Sargent with 7.56 inches falling in 1.5 hours and 10.72 inches in 3 hours this morning. This shows the potential of this air mass to produce excessive rainfall in a short period of time.
Heaviest Rainfall Expected Along US59
As the air mass heats late this morning, expect renewed development along/near the US 59 corridor.
Where exactly this band develops and how defined it becomes remains in question. But higher intensity rainfall rates will be possible in the afternoon and evening hours.
Rainfall Total Forecast
Expect an additional 2-4 inches with isolated amounts of 6 inches this afternoon through Thursday morning. Remember, 2 inches per hour can cause street flooding. Don’t drive through high water. Park your car on high ground.
To check the rainfall rate per hour, go to http://harriscountyfws.org, click on the a gage near you, then click the “for more information” link that pops up.
Posted by Bob Rehak on 9/18/19 at 10:45 am
750 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/09/image8-1.png?fit=725%2C408&ssl=1408725adminadmin2019-09-18 11:02:262019-09-18 11:08:16Center of Imelda Drifting Over SW Montgomery County as of Late Morning Wednesday
Here’s a river/lake report as of 7a.m. Wednesday, 9/18/19. During the early morning hours, TS Imelda was downgraded to a depression. The center of the storm moved north and is now over northern Harris County. Parts of the Lake Houston area received 4-5 inches of rain. Regardless, thanks to aggressive action by the City and luck in rainfall patterns, at this hour, no flood threat exists in our area from rivers or Lake Houston.
Little Rain So Far Upstream on West Fork
Rainfall around Lake Conroe overnight. Source: Harris County Flood Warning System
Luckily, very little rain fell upstream from us on the West Fork. In fact, the Lake Conroe area generally received less than a quarter inch of rain. Lake Conroe is releasing NO water at this hour. It’s level has not changed appreciably over night. It remains about 2.5 feet below normal.
West Fork and Lake Houston Still Below Normal Levels
Rainfall in Lake Houston Area. Source: Harris County Flood Warning SystemWest Fork status at Lake Houston Parkway. Source: Harris County Flood Warning System.
The West Lake Houston Parkway gage at the West Fork received a little more than four inches of rain in the last 24 hours. But the river is still within 6 feet of overflowing and the Lake itself is still about a foot below normal.
Source: USGS as reported by Coastal Water Authority.
Openning Gates Reduced Flood Threat
Source: Coastal Water Authority
Looking at the right of the graph above, you can see how yesterday’s decision to open the gates on Lake Houston lowered the level by an addition 1.3 feet. This helped offset the heavy rains that fell directly over the lake an in nearby tributaries.
The heaviest rain in the Lake Houston area appears to be 5.72 inches in Liberty County on the East Fork northeast of Lake Houston Park.
Overbank Flooding Limited to Southern Harris County So Far
The only flooding in Harris County from the heavy rains yesterday occurred in the extreme southern part of the county where the heaviest rains fell.
Flash Flood Watch Remains In Effect
Remain alert throughout today. A flash flood watch remains in effect for our area through tomorrow morning and will likely be extended.
Forecasters expect the heaviest rains with daytime heating. They predict that a band of rain will set up east of US59 this afternoon.
Conditions could change rapidly, especially now that the ground is fully saturated.
In the meantime, remain alert for street flooding and avoid travel if possible.
Posted by Bob Rehak on 9/18/2019 at 7 a.m.
750 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/09/Screen-Shot-2019-09-18-at-5.54.43-AM.png?fit=1870%2C1370&ssl=113701870adminadmin2019-09-18 06:45:182019-09-18 06:48:00Wednesday AM River, Lake Report: No Problems Yet
Overnight, the offshore low that had only a 10% chance of developing into a tropical system, turned into a tropical depression and then a tropical storm called Imelda.
Houston Under Flash Flood Watch
As of 6 p.m. Monday evening, Harris County and the entire Houston area is under a flash flood watch.
If the storm stays on its present trajectory, the center should go right through the Lake Houston area. Note in the graphic above that the heaviest rainfall will be east of US59 along a line between Houston and Livingston.
Rainfall Totals
The NWS predicts the three-day total rainfall for the storm could reach 6-8 inches, though professionals caution that much higher amounts are possible. For instance, if you live east of US59 and the track of Imelda, according to Harris County meteorologist Jeff Lindner, you might get up to 10-15 inches.
As the storm approaches from the southwest, the Lake Houston area will be on the dirty side, meaning we will get higher rainfall amounts than further west.
Lake Levels Down To Create Extra Buffer Against Flooding
However, effective immediately, the Lake level will be lowered to 40.9 feet, 2.6 feet below normal. This will create an extra buffer against flooding.
Houston City Council Member Dave Martin says, “All gates will remain open until the inclement weather threat leaves the area. After the weather threat has passed, gates will stay open until a level of 41.5 feet is reached allowing for the planned maintenance project to resume.”
Dry Ground Will Absorb Initial Rainfall, Then Look Out
Because of extremely dry weather during July, August and early September, the ground should absorb much of the initial rain. However, because the rate could exceed 1-2 inches per hour at times, runoff will rapidly increase.
The first threat from this storm will be street flooding. Secondarily, it will be bayou and river flooding. You can track the latter at Harris County Flood Warning System and make sure you check out their near-real-time inundation feature.
Protective Actions
Be Prepared. People should bring their pets inside and delay travel or outdoor activities during periods of heavy rainfall. If travel is unavoidable, reduce your speed to avoid hydroplaning.
If a Flash Flood Warning is issued for your area, DO NOT travel.
Property owners should ensure that street drains and ditches are clear of debris, so storm water can flow without obstructions. Blockages of drains, ditches, and culverts are the most frequent cause of flooding in neighborhoods.
Clear Street Drains
Secure items that might float away in heavy rain and become lodged in drains or culverts. Avoid street parking to protect your vehicle and allow clear passage for response vehicles.
Turn Around, Don’t Drown®
Do not drive through flooded areas. If you see water covering the road, do not attempt to cross it. Only a few inches of water can float a vehicle . If you find yourself in a dangerous situation where your vehicle is taking on water, get out of the vehicle, get to a higher position, and call 911.
Rain may move repeatedly across the same area, causing creeks and bayous to rise and possibly exceed their banks. Stay informed of current conditions and avoid traveling near creeks and bayous.
Avoid Traveling during Periods of Heavy Rain
Rain can reduce visibility and prevent you from seeing the road ahead, which could lead to accidents.
Posted by Bob Rehak at 6 pm Tuesday, 9/17/19
749 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/09/HGX_loop.gif?fit=600%2C550&ssl=1550600adminadmin2019-09-17 18:31:272019-09-17 18:39:42Lake Level Reports in Advance of TS Imelda; Where to Find Up-to-Minute Info During Storm
Center of Imelda Drifting Over SW Montgomery County as of Late Morning Wednesday
The National Weather Service has issued an urban and small stream advisory for the northern Lake Houston Area. It extends across north Houston up to Conroe. Expect street flooding.
According to Harris County meteorologist Jeff Lindner, the center of Imelda is drifting over southwest Montgomery County as of late Wednesday morning. Lindner adds that “lull” in heavy rainfall over Harris County should last until early afternoon. Expect rain to pick up significantly between mid afternoon and evening.
Flash Flooding Possible
The National Weather Service cautions that heavy downpours with rainfall rates between 2-4 inches per hour are possible. That’s enough to cause street flooding.
Incredible Rainfall Rates South of Houston
Incredible rainfall rates of 3-4 inches per hour have resulted in a 24 hour storm total of 21.34 inches at Sargent with 7.56 inches falling in 1.5 hours and 10.72 inches in 3 hours this morning. This shows the potential of this air mass to produce excessive rainfall in a short period of time.
Heaviest Rainfall Expected Along US59
As the air mass heats late this morning, expect renewed development along/near the US 59 corridor.
Where exactly this band develops and how defined it becomes remains in question. But higher intensity rainfall rates will be possible in the afternoon and evening hours.
Rainfall Total Forecast
Expect an additional 2-4 inches with isolated amounts of 6 inches this afternoon through Thursday morning. Remember, 2 inches per hour can cause street flooding. Don’t drive through high water. Park your car on high ground.
To check the rainfall rate per hour, go to http://harriscountyfws.org, click on the a gage near you, then click the “for more information” link that pops up.
Posted by Bob Rehak on 9/18/19 at 10:45 am
750 Days since Hurricane Harvey
Wednesday AM River, Lake Report: No Problems Yet
Here’s a river/lake report as of 7a.m. Wednesday, 9/18/19. During the early morning hours, TS Imelda was downgraded to a depression. The center of the storm moved north and is now over northern Harris County. Parts of the Lake Houston area received 4-5 inches of rain. Regardless, thanks to aggressive action by the City and luck in rainfall patterns, at this hour, no flood threat exists in our area from rivers or Lake Houston.
Little Rain So Far Upstream on West Fork
Luckily, very little rain fell upstream from us on the West Fork. In fact, the Lake Conroe area generally received less than a quarter inch of rain. Lake Conroe is releasing NO water at this hour. It’s level has not changed appreciably over night. It remains about 2.5 feet below normal.
West Fork and Lake Houston Still Below Normal Levels
The West Lake Houston Parkway gage at the West Fork received a little more than four inches of rain in the last 24 hours. But the river is still within 6 feet of overflowing and the Lake itself is still about a foot below normal.
Openning Gates Reduced Flood Threat
Looking at the right of the graph above, you can see how yesterday’s decision to open the gates on Lake Houston lowered the level by an addition 1.3 feet. This helped offset the heavy rains that fell directly over the lake an in nearby tributaries.
The heaviest rain in the Lake Houston area appears to be 5.72 inches in Liberty County on the East Fork northeast of Lake Houston Park.
Overbank Flooding Limited to Southern Harris County So Far
The only flooding in Harris County from the heavy rains yesterday occurred in the extreme southern part of the county where the heaviest rains fell.
Flash Flood Watch Remains In Effect
Remain alert throughout today. A flash flood watch remains in effect for our area through tomorrow morning and will likely be extended.
Forecasters expect the heaviest rains with daytime heating. They predict that a band of rain will set up east of US59 this afternoon.
Conditions could change rapidly, especially now that the ground is fully saturated.
In the meantime, remain alert for street flooding and avoid travel if possible.
Posted by Bob Rehak on 9/18/2019 at 7 a.m.
750 Days since Hurricane Harvey
Lake Level Reports in Advance of TS Imelda; Where to Find Up-to-Minute Info During Storm
Overnight, the offshore low that had only a 10% chance of developing into a tropical system, turned into a tropical depression and then a tropical storm called Imelda.
Houston Under Flash Flood Watch
As of 6 p.m. Monday evening, Harris County and the entire Houston area is under a flash flood watch.
For the latest updates visit the National Weather Service site.
Projected Path Of Storm Between US59 and I-45
If the storm stays on its present trajectory, the center should go right through the Lake Houston area. Note in the graphic above that the heaviest rainfall will be east of US59 along a line between Houston and Livingston.
Rainfall Totals
The NWS predicts the three-day total rainfall for the storm could reach 6-8 inches, though professionals caution that much higher amounts are possible. For instance, if you live east of US59 and the track of Imelda, according to Harris County meteorologist Jeff Lindner, you might get up to 10-15 inches.
As the storm approaches from the southwest, the Lake Houston area will be on the dirty side, meaning we will get higher rainfall amounts than further west.
Lake Levels Down To Create Extra Buffer Against Flooding
In advance of the storm, the Coastal Water Authority is lowering Lake Houston. The normal elevation is at 42.5 feet. As of this writing, the Coastal Water Authority shows the pool level at 41.19 feet, about 1.25 feet below normal for a planned maintenance project.
However, effective immediately, the Lake level will be lowered to 40.9 feet, 2.6 feet below normal. This will create an extra buffer against flooding.
Houston City Council Member Dave Martin says, “All gates will remain open until the inclement weather threat leaves the area. After the weather threat has passed, gates will stay open until a level of 41.5 feet is reached allowing for the planned maintenance project to resume.”
The SJRA has lowered the level of Lake Conroe according to its seasonal plan. Lake Conroe is currently at 198.71 feet, a little more than 2 feet below normal. The plan called for 199; evaporation took the rest. Currently the SJRA is releasing 0 cubic feet per second. Check the SJRA website for up to the minute reports.
Dry Ground Will Absorb Initial Rainfall, Then Look Out
Because of extremely dry weather during July, August and early September, the ground should absorb much of the initial rain. However, because the rate could exceed 1-2 inches per hour at times, runoff will rapidly increase.
The first threat from this storm will be street flooding. Secondarily, it will be bayou and river flooding. You can track the latter at Harris County Flood Warning System and make sure you check out their near-real-time inundation feature.
Protective Actions
Be Prepared. People should bring their pets inside and delay travel or outdoor activities during periods of heavy rainfall. If travel is unavoidable, reduce your speed to avoid hydroplaning.
Property owners should ensure that street drains and ditches are clear of debris, so storm water can flow without obstructions. Blockages of drains, ditches, and culverts are the most frequent cause of flooding in neighborhoods.
Clear Street Drains
Secure items that might float away in heavy rain and become lodged in drains or culverts. Avoid street parking to protect your vehicle and allow clear passage for response vehicles.
Turn Around, Don’t Drown®
Do not drive through flooded areas. If you see water covering the road, do not attempt to cross it. Only a few inches of water can float a vehicle . If you find yourself in a dangerous situation where your vehicle is taking on water, get out of the vehicle, get to a higher position, and call 911.
Monitor Official Sources for Current Information
Harris County Flood Warning System (harriscountyfws.org), Houston TranStar (houstontranstar.org), and the National Weather Service Houston/Galveston Forecast Office (weather.gov/hgx).
Monitor Stream, Bayou, and Creek Conditions
Rain may move repeatedly across the same area, causing creeks and bayous to rise and possibly exceed their banks. Stay informed of current conditions and avoid traveling near creeks and bayous.
Avoid Traveling during Periods of Heavy Rain
Rain can reduce visibility and prevent you from seeing the road ahead, which could lead to accidents.
Posted by Bob Rehak at 6 pm Tuesday, 9/17/19
749 Days since Hurricane Harvey