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Detention Pond Construction: Montgomery vs. Harris County

Below are aerial images from two new developments under construction. They show two detention ponds in two different counties. Can you tell which is in Montgomery County and which is in Harris County? I took both photos on the same day, 2/13/2020.

Clue

Look where the grass has established itself:

In A, the land was cleared before the detention pond was completed.
In B, the detention pond was completed before the land was cleared.

And the Answer Is…

If you guessed that Pond A is in Montgomery County, you guessed correctly. Pond A is in Woodridge Village, just north of Sherwood Trails and Elm Grove. It is their S1 detention pond (first southern).

Pond B is in Harris County just north of Bush Intercontinental Airport and Mercer Botanic Gardens.

How You Can Tell

Montgomery County does not require developers to install detention ponds before they clearcut the whole development. So they sometimes come long AFTER clearcutting.

Also, even though Page 44 of Montgomery County’s Drainage Criteria Manual says that “slopes must be revegetated immediately after construction to minimize erosion,” no one apparently enforces the regulation. The sides of Pond A have gone without grass for about a year. See close up below.

*Erosion on the sides of Pond A shown above, the Woodridge Village S1 detention pond.*

All 268 acres of Woodridge Village have been clearcut for the better part of a year. Meanwhile Perry Homes and its engineering firm LJA are just now taking bids on additional detention ponds for the northern section. And the sides of Pond A still have yet to sprout grass.

Harris County Regs Differ

Note in the Pond B photo how the sides of the channel have been stabilized with grass before the developer has even finished clearing the land.

Harris County employs low-impact development procedures (LID). Harris County Stormwater Quality Management regulations discourage clearcutting giant sites like Woodridge Village all at once. See section 4.2.3.1, Stormwater Pollution Prevention (SWPPP) During Construction.

The text states, “The clearing, grubbing and scalping (mass clearing or grading) of excessively large areas of land at one time promotes erosion and sedimentation problems. On the areas where disturbance takes place the site designer should consider staging construction [emphasis added], temporary seeding and/or temporary mulching as a technique to reduce erosion. Staging construction involves stabilizing one part of the site before disturbing another [emphasis added].”

Two Different Approaches

You would think that preventing erosion would be cheaper than cleaning it up. Why do a job once when you can do it twice? Right?

*Close up of remediation work in Pond A, from a slightly different angle.* *Photo taken 2/13/2020.*

Evidently, Perry Homes prefers it that way. Last Thursday, I spotted men digging out the pilot channel of Pond A and restoring slopes…again. This was at least the third or fourth time. No wonder those Perry Homes are so expensive.

Posted by Bob Rehak on 2/16/2020

901 Days After Hurricane Harvey and 150 after Imelda

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.

Part II: When Is A Detention Pond Not A Detention Pond?

Q: When is a detention pond not a detention pond?
A: When it’s just a wide spot on a stream.

The defining characteristic of a detention pond is an “outfall” smaller than the inlet. The pond holds back rain in a storm and releases it later at an acceptable rate. This reduces downstream flooding.

*From the Montgomery County Drainage Criterial Manual*

That’s the theory, at least. In practice, sometimes things don’t always work out that way. It often depends on maintenance.

Unrestricted Outfalls

On 2/13/2020, I reported on one Woodridge Forest detention pond on Ben’s Branch that had an outfall LARGER than its inlet. Harvey and Imelda blew out the pond’s outfall.

This week, I discovered that a second pond immediately upstream also apparently has an unrestricted outfall.

*Two tributaries of Ben’s Branch come together in the foreground pond. The pond also collects runoff from surrounding commercial and residential areas.* *Photo taken 2/13/2020.*

*Water flows toward exit in upper right.* *Photo taken 2/13/2020.*

*Note height and width of exit.* *Photo taken 2/13/2020.*

The low area in the picture above measures more than 200 feet wide in Google Earth. That’s far wider than the combined inlets. Net: this pond provides little if any detention capability.

Same Problem with Second Pond

Neither does pond beyond it that I highlighted last week provide much detention capacity.

*Note how Ben’s Branch flows both through and around the next pond. Direction of flow is from bottom to top of frame.* *Photo taken 2/13/2020.*

*Reverse angle looking NW. Direction of flow is now toward camera.* *Note how the outfall (foreground) is larger than the inlet. Also note how runoff from residential streets (upper right) is channeled outside the pond. Photo taken 2/13/2020.*

Both Ponds Provide Little Detention Benefit, If Any

Both of these ponds provide little detention benefit, if any.

Neither pond has a maintenance road around it, even though Section 7.2.8 of the Montgomery County Drainage Criteria Manual specifies that “A 30-foot wide access and maintenance easement shall be provided around the entire detention pond.”

Sometimes, what looks like a detention pond is really just a pond. Or a wide spot in a stream.

Recent Surge in Downstream Flooding

During the May 7th and Imelda floods in 2019, water flowing through these ponds then flowed over Northpark Drive and flooded homes in North Woodland Hills. It also flooded numerous homes and businesses downstream on Ben’s Branch between Woodland Hills Drive and the San Jacinto River West Fork.

One wonders whether those damages could have been averted if the ponds had detained water.

As Harris County Flood Control conducts the Kingwood Area Drainage Study, engineers must consider the possibility that this area may be dumping more water downstream than planned.

The Woodridge Municipal Utility District apparently is responsible for these ponds.

Posted by Bob Rehak on 2/16/2020

901 Days after Hurricane Harvey and 150 after Imelda

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.

Take Down: West Fork Mouth Bar

DRC (Disaster Recovery Corporation) excavators are slowly whittling down the mouth bar of the West Fork of the San Jacinto. DRC is picking up where the Army Corps and Great Lakes Dredge and Dock left off around Labor Day last year. The Corps and Great Lakes removed 500,000 cubic yards of sediment. DRC will remove another 400,000 in 8-12 months as part of its contract.

DRC Focus Differs from Corps’ So Far

The Corps effort focused on deepening the channel between the mouth bar and Atascocita Point. DRC’s effort appears to focus on reducing the mouth bar itself.

A survey conducted after the Corps finished in September showed they had reduced the average depth in front of the mouth bar to about 5.5 feet. Local residents including high-level geologists questioned whether that was enough to restore safety. They pointed out that the river upstream of the mouth bar had been dredged to more than 25 feet and worried that the 20 feet difference would partially dam the river during floods and create a backwater effect that contributed to flooding.

But instead of deepening the channel, the next phase of dredging seems aimed at reducing the mouth bar itself.

Progress to Date in Reducing Mouth Bar

Aerial photos taken on 2/13/2020, show that to date DRC has removed most vegetation from the bar. They have also reduced the crown of the bar and flattened it to create a platform for excavator(s) that’s little more than a foot or so above the water. Parts of the bar used to stand four to five feet above water.

While two excavators worked on the scalping process Thursday, a third took bites from the edge of the bar, much like a human might nibble away at an ear of corn, row by row.

*On Thursday, 2/13/2020, three excavators worked various portions of the mouth bar.*

*Two were still leveling the bar and removing vegetation while a third whittled down the edges of the bar.*

*The excavator near the water appears to be walking backward as it pulls sediment from in front of it and dumps it on the waiting pontoon.*

*When the pontoon is full, a small tug pushes it upstream*.

Placement Area for Sediment

Tugs push the pontoons upstream to Berry Madden’s property on the south side of the West Fork, just upstream from Kings Lake Estates, roughly opposite River Grove Park.

*…through the back channels of the West Fork to Berry Madden’s property, the placement area. Photo courtesy of Josh Alberson.*

*At Madden’s property, the sediment is offloaded.* *Photo courtesy of Josh Alberson.*

*The tug will then take a pontoon back downstream for the next load.*

*The sediment will then get loaded into dump trucks…*

From the number of trucks on Madden’s property, it appears that DRC is using it as its command post for the operation.

*Bulldozers then compact the dirt and spread it out.*

Operational Tempo Expected to Increase

Josh Alberson, a local boater, monitors the dredging program. He says that the cycle time per pontoon load has decreased from roughly three hours to about two hours and twenty minutes.

Berry Madden, the placement area owner, says DRC has told him that it expects to add more equipment to the job by next week. That should increase the operational tempo and the volume of sediment transported each day.

Madden’s property is also permitted to receive spoils from hydraulic dredging.

The Harris County Engineering Department is managing this project with the City of Houston.

Next Steps Still Unclear

The Harris County Engineers office has not yet released plans for the remainder of the project. Several things remain unclear at this point. Key among them:

Why remove the mouth bar instead of deepening the channel in front of it?
Will the operation switch over to hydraulic dredging to speed up the project and reduce the flood-risk window?
What will the next steps be after completion of the West Fork?
Have the partners agreed on a maintenance dredging program?

The grant request submitted by the County to the TWDB indicates that the team also expects to tackle the rapidly growing East Fork mouth bar. During Imelda, boaters say the channel north of Luce Bayou silted in badly. It went from 18 feet deep to approximately 3 at the deepest point, they say.

Posted by Bob Rehak on 2/15/2020 with photos from Josh Alberson

900 days after Hurricane Harvey

Corps, Contractors Vacate Old Dredging Command Post, Demobilize

The Emergency West Fork Dredging Program started by the Army Corps of Engineers in May of 2018 is now virtually done with demobilization. In the last month, the Army Corps and its contractors have vacated the old command post they established on the south side of the San Jacinto West Fork opposite Forest Cove. They have removed the remaining pieces of the Great Lakes dredge, dredge pipe, booster pumps, construction trailers, cranes and more.

Nothing Remains But Sand and Memories.

As I flew over the site on 2/13/2020, men were removing two small bulldozers, the last pieces of equipment. Here’s how it looked from the upstream side.

*The once bustling Army Corps Command Post for the Emergency West Fork Dredging Program after Harvey. Photo taken 2/13/2020.*

Here’s how it looked from the downstream side.

*Reverse angle of same location, looking west toward US59.*

How Same Site Looked Three Weeks Ago

Less than a month ago, on my January 20th flyover, the site still bustled with activity. Demobilization was in full swing.

*Army Corps Command Post on January 20, 2020.* *Looking East.*

*Pieces of the Great Lakes dredge at the Army Corps Command Post on January 20, 2020.*

They say, “It ain’t over till it’s over.” Well, I’d say that the Emergency West Fork Dredging program that started in 2018 is now over.

Altogether they removed approximately 2.3 million cubic yards of sediment clogging the West Fork that Hurricane Harvey deposited.

Moving On to Next Phase of Dredging

This, however, does not affect the current mouth bar dredging program. That is a separate effort mounted by the State of Texas. Harris County and the City of Houston.

Grants from FEMA and the Texas Water Development Board, plus money from the 2018 Harris County Flood Bond fund the current program.

It uses mechanical, not hydraulic dredging equipment. The focus of activity is farther downstream closer to the West Fork Mouth Bar.

Bald Eagle Sighted Over Romerica Property

*Photo taken 2/12/2020 on West Fork San Jacinto from helicopter.*

While photographing the West Fork from a helicopter Thursday, I saw something large from the corner of my eye. I looked up and was treated to a magnificent sight – a bald eagle in flight … right beside us. I quickly zoomed my lens out to 300mm and snagged this air-to-air shot.

We were in the vicinity of the Romerica property just downstream from River Grove Park. You may remember a year ago that two developers from Mexico wanted to build 500-foot high-rises right next to the river. The community rose up in protest. One of the biggest concerns: the effect on bald eagles nesting in the area.

The US Fish and Wildlife Service wrote a scathing letter urging the Corps to deny Romerica’s application to fill in wetlands.

After 770 more letters of protest to the Corps, the Corps withdrew Romerica’s permit application.

The company reserved the right to refile in the future. In the meantime, it appears that the eagle(s) living there have no intent to move.

The Herons Kingwood recently took down its website. However, the domain name is still registered. I have contacted the agent for the company to inquire about the project’s status. Emails have not yet been returned.

Posted by Bob Rehak on 2/13/2020

899 Days after Hurricane Harvey

HCFCD Launches Channel Repair Projects in Walden on Lake Houston and Kingwood

Yesterday, a reader, Donna Hanna Dewhirst, sent me pictures of a dredging operation beginning in the channel that cuts through Walden on Lake Houston. Today, I photographed it from the air.

Walden Project Kicks Off

*That’s the Walden Mouth Bar in the distance. So far, though, dredging activity has focused upstream near the country club.*

*HCFCD classifies the project as a repair, though it is not yet listed on HCFCD’s repair page for this area.* *Photo by Donna Hannah Dewhirst.*

*De-watering the spoils before transport*. *Photo by Donna Hannah Dewhirst.*

Typically, in a project with wet dirt like this, contractors “de-water” it by letting it drain on the banks for a while. Once dry, they haul it away. HCFCD sent dirt from Ben’s Branch to a cleaning facility to ensure they weren’t transporting any dangerous bacteria or organisms living in the mud. From there, it’s reused in landscaping and other projects.

*Reverse angle, looking upstream toward excavation in background on left.*

Reader Jeff Bayless volunteered, “This is called Rogers Gully and drains a large part of Atascocita. This is actually the 2nd time they have removed sediment from this location. They finished the first round right before Imelda and lined the banks with riprap and fresh top soil further upstream all the way to Framingham Road. Had it looking good then Imelda hit and washed all their new soil back into the downstream parts by the County Club. This also made the mouthbar in the lake larger and shallower. My fear with the large mouthbar is if Atascocita gets a Kingwood May 7 type flash flood, the mouthbar will push drainage water into the homes along this gully. Hopefully the mouthbar removal is a real project that will happen before flooding occurs.”

Series of Ditch Repairs Begins in Kingwood

Work on Ben’s Branch is now approximately 50% complete, according to Beth Walters of HCFCD.

Meanwhile, more channel repairs have started in Kingwood within the last few weeks. They consist primarily of erosion and outfall pipe repairs. Repairs are so numerous, HCFCD had to group them into a a series of smaller projects to expedite bidding and repairs. The project include:

G103-41-00-X008: Two damage sites (5622 and 5622A) consisting of slope erosion, toe line repair, and channel scour.
G103-38-00-X020: Three damage sites (5416, 5680, and 5682) consisting of bank sloughing and erosion repair.
G103-38-01-X014: A series of voids on the southern side of the channel. One void is very large and the concrete paving has begun buckling. Another void is above an outfall pipe that will need to be replaced. Access is limited and encroachments are present.
G103-38-00-X021: Slope erosion has progressed and will eventually begin to affect the concrete channel lining. Also, some sediment has built-up and needs to be removed.
G103-38-01-X010: One damage site consisting of slope erosion.

To see the locations of these channels, zoom waaaaay in on the map.

Funding for most of these repairs comes from NRCS (Natural Resources Conservation Service), which is part of the US Department of Agriculture.

Posted by Bob Rehak on 2/13/2020 with photos from Donna Hannah Dewhirst

899 Days since Hurricane Harvey

When Is a Detention Pond Not a Detention Pond?

On a flyover of the Harris/Montgomery county line last month, I spotted something unusual: a detention pond with an outlet bigger than its inlet. And it was in Woodridge FOREST. You may remember that after Imelda, Woodridge Forest advertised homes that did not flood on signs posted in nearby intersections…around downstream homes that did flood!

Detention Pond that Isn’t

*Wide shot, looking east toward St. Martha’s Catholic Church and Kingwood Park High School. Photo taken 1/20/2020.*

Below is a closeup of the suspect pond cropped from the image above.

Water flows from bottom left to upper right in this image. During Harvey, the outlet for this detention pond blew out. Imelda enlarged it even more. No one has repaired it, meaning it retains no water in a flood.

*Water from this part of the subdivision does not even go through the pond.* *Note the location of this outlet in the photos above and below.*

*Satellite image shows clearer comparison. Detention pond has bigger outlet than inlet and a creek that runs around it.*

Detention ponds usually work by capturing water coming in a fast rate, storing it, and releasing it at a slower rate that minimizes downstream flooding.

*From Montgomery County Drainage Criteria Manual*

This pond provides very little, if any detention capacity. In fact, Ben’s Branch runs BOTH around and through it!

The berm that forms the north side of the pond in the image above does little more than take up valuable space in the flood plain.

On its way from 59 to Woodland Hills, Ben’s Branch goes through a series of “detention ponds” along the southern edge of Woodridge Forest. What purpose does of this one serve? And are the others doing their job?

Developers/HOAs Responsible for Maintenance

In Montgomery County, developers or HOA’s must maintain their own detention ponds (see section 7.2.8). But do they? No one seems to inspect their work. The damage to this pond initially happened after Harvey, almost 900 days ago. Then Imelda damaged it more, almost 150 days ago.

The pond should also have a 30-foot wide maintenance road around it (also section 7.2.8), but does not. The developer built the pond in 2016, but no one seems to have noticed the absence of the maintenance road yet. That missing maintenance road might have helped in the repair of the pond after Harvey.

And the “Rub-Your-Nose-In-It” Award Goes To…

Who knows how much this pond could have helped reduce flooding on May 7th and September 19th last year?

Many who flooded in North Woodland Hills and Bear Branch sure would like to know.

The truly appalling thing about this: shortly after Imelda, Woodridge Forest posted signs in the area informing buyers, “We don’t flood.” Well, when you’re not retaining all the water you should…

Montgomery County is on an unsustainable path. Every week, I get complaints from Montgomery County residents about flooding there. MoCo is already starting to reap what it has sown. Someday, MoCo, too, will be downstream from another rapidly growing county. And then the tragic precedent MoCo has set will make payback inevitable.

Posted by Bob Rehak on 2/13/2020

898 Days since Hurricane Harvey and 147 since Imelda

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.

Latest Sand Mine Breaches and Near Breaches

In the continuing saga of sand mining on the East and West Forks of the San Jacinto, I present the results of my January 20, 2020, flyover. I found three breaches and two near breaches between I-45 and the East Fork. See below.

Liberty Materials Mine in Conroe

Let’s start upriver on the San Jacinto West Fork near Conroe. These first two images come from the Liberty Materials Mine that the TCEQ cited for allegedly discharging 56 million gallons of white slime into the river.

In this photo you can see that road (upper right) has repairs blocking a previous breach. However, discharge continues to flow through the dike. This indicates potential structural instability that might jeopardize the dike in a major flood and cause another massive discharge.

A couple hundred yards away at the same mine, there’s so little road left, driving a car across it could cause collapse of the remaining dike. That jeopardizes safety of workers and the safety of drinking water. Only four or five feet separates a massive mining pond from the West Fork in the foreground.

There sure is a lot riding on that little spit of sand. If this one blows out, I pray the TCEQ and Attorney General goes after them for gross negligence. How could they ignore this?

Hallett Mine in Porter

The next two shots come from the Hallett Mine in Porter. They show the same issue from two different angles.

*Looking toward the West Fork. Another portion of the mine lies on the far side of the river.*

Abandoned Mine in Porter

This is the drainage ditch that parallels Northpark Drive before it enters the river. This mine appears to be abandoned. Regardless, sediment, seems to consistently wash out of it. This breach has been open for since 2015.

Triple PG Sand Mine in Porter on Caney Creek

The Attorney General is suing this mine for breaches that remained open for months after the May floods last year. Currently, the mine is operating (but not dredging) under a temporary injunction until the case goes to trial on June 22. While mine owners have closed other breaches on White Oak and Caney Creeks, this breach remains open. Technically, it doesn’t connect with with river until a flood. But during floods, photographic evidence shows that Caney Creek reroutes itself through the mine, raising pressure that causes dikes in other places to collapse.

The shot below shows headward erosion toward five pipelines carrying highly volatile liquids.

Such breaches and near breaches create a good argument for creating minimum setbacks for mines from the creeks and rivers that supply our drinking water.

Sadly, legislation that could have done that died in committee during the last session. But there’s always next year. I will continue to monitor how well the mines do until new measures can be reintroduced. Pressure is building throughout the state to control air and water pollution from aggregate mines.

Posted by Bob Rehak on 2/12/2020

897 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.

Flood Insurance: Two Types

I have a friend who is fond of saying, “If rain falls on your roof, you need flood insurance.” Here are two telling statistics from the final Harvey report issued by Harris County Flood Control that dramatize that point. But there’s more than one type of flood insurance.

In Harvey, Two-Thirds of Flood Victims Had No Insurance

Of the 154,170 estimated homes flooded across Harris County from Harvey, only 36% had active flood insurance policies in place.

Of those 154,170 homes flooded, 105, 340 were outside the mapped 1% (100-yr) floodplain – 68%.

From these two statistics, you can tell that people thought being outside a mapped flood zone meant SAFETY. You can also see how tragically wrong they were.

Virtually ALL Humble Area Retired Teachers Have Flood Insurance

Monday morning I gave a talk to the Humble Area Retired Teachers Association (HARTA). There were probably 150-200 teachers in the room. I asked for a show of hands to see how many had flood insurance. Virtually every hand went up. Given the aforementioned statistics, this SHOCKED me.

There are two possibilities.

People learned a lesson from Harvey and Imelda.
The teachers in the room were smart!

I’m sure it’s a combination of both in this case. Teachers tend to be fast learners. But it was such a pleasant surprise. They set a great example for everyone!

FEMA needs to study HARTA to find out how to market flood insurance to the rest of the world.

Static Maps in a Changing World

How could the flood maps during Harvey have been so far off? It was a combination of things.

Of course, Harvey was a far larger-than-normal storm – the biggest ever to hit the continental US.

Second, flood maps are a stationary snapshot in time. They assume nothing changes.

But we also know that things DO change:

The river changes every time it floods.
There has been massive development upstream from us in Montgomery County in the last two decades.
Conroe has been one of the fastest growing cities in America.
That development increases runoff, shortens the time of accumulation for floodwaters, and causes higher flood peaks.

The one thing that hasn’t changed: Montgomery County flood maps. The County has not updated the data behind them since the 1980s. Parts of the county remain unmapped. And the County does not even employ a surveyor, according to an inside source.

Radical Example of Impact of Upstream Development

Uncontrolled upstream development can totally change the game. Here’s a personal example.

Back in 1980, I bought a home on Spring Creek in the Dallas area. It was built two feet above the hundred year flood plain. The next year, developers built the 250-acre Collin Creek Mall upstream from me in Plano. The creek behind my house started flooding on minor rains of less than a half inch. A three city commission between Garland, Richardson and Plano asked the Army Corps to investigate.

The Corps found that I was now 10 feet BELOW the 100-year flood plain instead of two feet ABOVE it. A 12-foot delta!

That’s how radically and quickly things can change from upstream development as the people in Elm Grove discovered.

*Elm Grove’s Game Changer: Woodridge Village or what some now call* “Village of the Damned“

New Flood Maps Being Developed

NOAA’s new Atlas-14 Rainfall statistics for this area are causing flood maps to be redrawn. The statistics reflect about 40% more rain for a 100-year flood. That means flood zones will expand.

When released in the next year or two, the new maps will open a lot of eyes for people who have not yet purchased flood insurance.

Net: If you don’t have flood insurance, get it.

Another Type of Flood Insurance

That brings us to another type of flood insurance not covered by FEMA’s National Flood Insurance Program. It’s the kind of insurance that comes from situational awareness and community engagement.

The more aware we are of the causes of flooding…

The more engaged we are as citizens…

The more we insist that developers follow best practices…

…the safer we become.

NFIP insurance will partially reimburse you if you flood. But awareness and activism may keep you from flooding in the first place. We need both types of insurance. One without the other is a recipe for disaster.

We should not assume that some benevolent government agency in Montgomery County is watching over new development, protecting us. They are not. Period. They have other priorities and protecting downstream residents is rarely one of them. Even though Harris County is redrawing its flood maps, Montgomery County is not. That will make MoCo’s even MORE OUTDATED. That’s why we need vigilant, involved citizens.

Need Regional Flood Control

And even more, that’s why we need regional flood control, much as we have regional groundwater control. With groundwater withdrawals, one conservation district must get its plans approved by neighboring districts. Wouldn’t it be beautiful if we had a similar arrangement for flood control?

Posted by Bob Rehak on 2/11/2020

896 Days after 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.

Rain Forecast This Week

Jeff Lindner, Harris County Meteorologist but put this notice thus morning. He said wet weather will persist until mid week.

Slow-Moving Cold Front Stalls Out

A slow-moving cold front currently extends from Longview to north of Austin and is creeping southward. Ahead of this boundary a warm and moist air mass covers all of SE TX this morning. Meanwhile, north of the boundary a colder and somewhat drier air mass is in place.

Radar is fairly calm this morning with a couple of lines of showers lifting north over the region in the warm air advection pattern in place.

Surface cold front will move to near a Madisonville-to-College-Station line later this morning and then likely stall in that region today. Focus for rainfall today will be mainly across the northern half of the region closest to the front. Rainfall amounts today could average 1-2 inches north of HWY 105 as another upper level disturbance approaches from the WSW and interacts with the slow moving front.

Front Pushes South Tonight

Front will get another push this evening and likely progress southward toward the coast tonight. With the afternoon and evening short wave disturbance moving off to the ENE expect a lull in any heavier rains by late evening across the northern portions of the area.

Mainly light showers will impact the southern portions of the area this evening and overnight as the surface front stalls near the coast.

Tuesday Front Lifts Back North

On Tuesday the surface front begins lifting back northward as a warm front with a continued chance of showers over the area.

A strong upper level storm system currently digging into NW Mexico will begin to move slowly eastward and toward TX late Tuesday into Wednesday. This will result in the formation of a surface low pressure system over the coastal bend of TX Tuesday night which then moves ENE/NE across SE TX Wednesday.

Showers and thunderstorms will be likely in this period with some heavy rainfall possible.

Clearing Late in Week

This surface low will be strong enough to finally push a stronger front through the region and clear the area out for at least a couple of days before clouds and rain chances return for the weekend.

Yo-Yo Temperatures

Temperatures will be all over the place with the surface front stalling and then creeping across the area. Ahead of the front temperatures will be in the 70’s and then fall into the 60’s and possibly 50’s behind the boundary.

Rainfall 1-4 Inches, Highest to North

Rainfall Amounts:

Fairly tight rainfall gradient will setup across SE TX over the next 72 hours with much of the rainfall occurring north of HWY 105 and much lower amounts near the coast.

Storm total rainfall amounts through Thursday morning will likely average 1-2 inches over much of the region north of I-10 and 3-4 inches in the Lake Livingston area.

South of I-10 amounts of .50-1.0 inch will be possible. While the drought monitor shows dry conditions over much of the area, the time of year combined with lack of any vegetation growth and the widespread nature of the expected rains suggest rises on area creeks and rivers will be likely.

Highest impacted watersheds look to be the mainstem and tributaries of the Trinity River and the San Jacinto basin.

Currently predicted amounts are spread out enough to preclude any forecast to reach flood stage, but we will need to watch rainfall trends today and again on Tuesday especially north of HWY 105.

Should rainfall totals begin to pile up in our NE counties (Polk, Trinity, Houston, San Jacinto) a flash flood watch could be required for those areas.

Excessive Rainfall Outlook (Monday):

*The Lake Houston area has only a marginal to slight risk of excessive rainfall today.*

Excessive Rainfall Outlook (Tuesday):

*Tuesday, the risk for excessive rainfall in our area looks mostly marginal.*

Day 1-3 Forecast Rainfall Amounts:

*Rainfall in the 3 day period should total 1-4 inches. Higher totals to the north. Lower to the south.*

Posted by Bob Rehak on 2/10/2020 with thanks to Jeff Lindner

895 Days since Hurricane Harvey