Tag Archive for: Marco

Remember Uncertainty With Marco, Laura; It’s Why We Need More, Bigger Gates on Lake Houston

Many anxious flood victims worry openly on social media about about the possibility of flooding by back-to-back tropical events. Should we lower Lake Conroe? Is it too late? Will we flood again? Why aren’t they releasing water?

The novelty of having two tropical storms in the Gulf simultaneously has added a high degree of uncertainty to weather forecasting at the moment. The forecast tracks, intensities and dangers of Marco and Laura seem to change every few hours.

This is precisely why we need more and bigger flood gates on Lake Houston.

By the time we are certain what will happen with these storms, it will likely be too late to release water if we need to.

The bewildering multitude of competing weather forecast models complicates matters. They show landfall anywhere from Corpus Christi to the Mississippi just two days before the storms’ arrival. It reminds me of a fortune cookie I once got. It said, “A man with two clocks never knows what time it is.”

Marco Weakening Before Making Landfall

Since this morning, the cone of uncertainty for Marco has shifted inland again and the storm has been downgraded to a tropical depression. The only coastal watches or warnings remaining in effect have to do with Laura which will follow Marco later this week. (See more below.)

As of 4pm CDT on Monday 8/24/2020. Source for all graphics: National Hurricane Center.

The National Hurricane Center shows only a slight chance of flash flooding for the areas hit directly by Marco and those are far east of us. Rainfall potential from Marco through Wednesday evening for the Houston Area is less than an inch, according to the latest NHC predictions.

At 1 p.m. Monday, the NHC issued an advisory stating that, “It is reasonable to assume that sustained tropical storm force winds will no longer reach the northern Gulf coast. Therefore, all wind and surge warnings for the Gulf coast associated with Marco have been discontinued.”

Laura Remains Potent Threat

Even though Laura’s cone of uncertainty has shifted slightly east today, the Houston Area remains on the western edge of the cone.

At the moment, NHC predicts Laura will bring Houston 2-4 inches of rain, and the Lake Conroe area less than 2.

That’s enough to raise the chance of flash flooding to 5-10%.

Laura’s maximum sustained winds are near 60 mph with higher gusts. NHC predicts little change in Laura’s strength today, but predicts the storm will strengthen when it moves into the Gulf of Mexico. They foreast Laura will become a hurricane on Tuesday, with additional strengthening on Wednesday. Tropical-storm-force winds currently extend outward up to 175 miles, primarily to the northeast and east of the center. As Laura approaches the Gulf Coast, swells will cause life-threatening surf and rip-current conditions.

Tropical storm force winds should reach the Texas coast between 8 a.m. and p.m. on Wednesday. Most of the Houston Area will have a 40-50% chance of experiencing winds greater than 39 mph.

Alert Houston has just issued the following notice:

“The National Weather Service has issued a Tropical Storm Watch for Houston. Coastal portions of the city are also under a Storm Surge Watch. Although the exact track and intensity of Laura is still unknown, Houston residents should pay close attention and begin taking steps in the event an emergency situation develops.”

Jeff Lindner, Harris County Meteorologist, put a finer point on it. “Tropical storm force winds are likely along and east of I-45 with sustained winds of 35-45mph across portions of Galveston, Harris, Montgomery and Walker Counties. Strong winds of 45-55mph will be possible across Chambers, Liberty, San Jacinto, Polk, and Trinity Counties. It is possible that near hurricane conditions could scrape close to eastern Chambers and eastern Liberty counties.”

To Lower or Not to Lower, That is the Question

So with:

  • People panicking
  • Forecasts changing hourly
  • Lake Conroe Association restocking its war chest
  • Wildfires burning up the west
  • Drought spreading into parts of Texas
  • The Nation’s foremost hurricane experts predicting only 1-2 inches of rain for Lake Conroe and 2-4 for Lake Houston…

…what do you do? Order the lakes lowered or keep them where they are?

Source: https://www.drought.gov/drought/states/texas

The answer is obvious. You enlarge the discharge capacity of Lake Houston by adding more and bigger gates to the spillway.

Gates on Lake Houston have one-fifteenth the discharge capacity of those on Lake Conroe.

Lake Conroe can release water 15 times faster than Lake Houston. 150,000 cubic feet per second vs. 10,000. With that in mind, the likelihood, at this hour (5pm Monday), is that water released from Lake Conroe could not get into the Gulf before Wednesday when the storms arrive.

And that, in a sentence, is why we need more and bigger flood gates on the Lake Houston Dam. Remember Marco and Laura, and that knot in the pit of your stomach, the next time the subject of gates comes up.

By the way, neither Lake Conroe, nor Lake Houston, is releasing water at this time. Lake Conroe is at 199.76 feet above sea level and Lake Houston is at 41.6 feet. Both are already below their normal levels, though not as low as many would prefer. At 4:24 this afternoon, the SJRA issued a press release saying that, “We continue to watch Laura closely. Right now the projected totals of rainfall in the Lake Conroe watershed are very low.”

Posted by Bob Rehak on 8/24/2020 at 5 pm

1091 Days after Hurricane Harvey

Marco Downgraded to Tropical Storm, But Track Shifts Toward Houston; Laura Could Hit Coast as Cat 2 or Higher

At 7:00 a.m. CDT Monday, Tropical Storm Marco was moving north toward the mouth of the Mississippi at 10 mph. The National Hurricane Center predicts Marco will approach the Louisiana coast this afternoon, and then turn west toward Houston/Galveston, following the coast through Tuesday night.

NHC expects Marco to become a tropical depression late on Tuesday and dissipate on Wednesday over southeast Texas. Tropical-storm-force winds extend outward up to 105 miles (165 km), primarily northeast of the center.

Maximum sustained winds have already decreased to near 60 mph with higher gusts.

As One Storm Dissipates, Another Arrives

As Marco is breaking up, Laura could arrive as a Category 2 or higher hurricane.

The NHC still gives the Houston Area a 50-60% chance of experiencing tropical storm force winds, most likely from Laura (see below).

The most likely time for arrival of those winds is during the day on Wednesday.

Laura continues to move quickly WNW at near 21 mph.

“Details of when Laura will turn toward the NW and N and where the core of the system will cross the coast over the NW Gulf remain unclear,” says Jeff Lindner, Harris County Meteorologist.

The official NHC forecast brings Laura toward the TX/LA border, but landfall could be as far west as Galveston Bay and as far east as Vermillion Bay.

Models still show a wide spread of possible landfalls, but the largest cluster is on the TX/LA border.

Lindner says, “It is important to not focus solely on the exact landfall points as Laura will be a large hurricane with far reaching impacts.”

Laura Intensity

Laura is disorganized this morning. Likely little will change in Laura’s overall intensity today, due to interaction with the Cuban landmass. Once Laura reaches the SE Gulf of Mexico on Tuesday, intensification is likely.

“It is unclear how quickly the inner core of Laura will form. Broad systems such as Laura tend to take time to develop,” says Lindner.

Laura will likely reach hurricane status over the central Gulf and be near major hurricane status over the NW Gulf on Wednesday.

Jeff Lindner, Harris County Meteorologist

Impacts from Laura

As of 7 a.m., NHC advises, “From late Wednesday into Friday, Laura is expected to produce rainfall of 5 to 10 inches, with isolated maximum amounts of 15 inches near the Texas/Louisiana border. This rainfall could cause widespread flash and urban flooding, small streams to overflow their banks, and the possibility of some minor river flooding across this region.”

However, if the storm stays on its current course or shifts farther east, the amount of rainfall in the Houston Area will lessen. As of 4 a.m. this morning, Lindner predicted rainfall of:

  • 2-4 inches east of I-45 
  • 1-3 inches west of I-45

Squalls will begin to arrive along the upper TX coast Wednesday and increase into Wednesday night and Thursday.

Tides/Storm Surge: 

Laura will cause a large storm surge near and to the east of where the center crosses the coast. Significant swells will begin to arrive on Tuesday. This will likely drive water levels upward along the Gulf beaches and into Galveston Bay, especially at high tide. 

Note: water level rises will likely begin along the coast early Wednesday.


Sustained winds of 35-45mph will be possible east of I-45 with lower speeds west of I-45. Winds may gust higher in squalls especially over Chambers, Liberty, eastern Harris, and Galveston counties. Any shift west in the forecast track will bring stronger winds into the area.  

Sustained tropical storm force winds arrive along the upper TX coast by early evening on Wednesday.


Preparations for the landfall of a hurricane along the SE TX or SW LA coast should be underway.

Enact hurricane plans and follow all advice and recommendations from local elected officials and emergency management agencies.

Residents near the coast in evacuation areas, should review plans and react quickly should any evacuation recommendations be ordered.

Keep gas tanks full.

Posted by Bob Rehak on 8/24/2020

1091 Days after Hurricane Harvey


Lastest NHC Forecasts Show Marco, Laura Slamming Louisiana

Updates on Tropical Storm Marco and Laura issued by the National Hurricane Center at 5 p.m. EDT show both storms aiming toward Louisiana at this point. That doesn’t mean the Houston Area is out of the woods. The forecasts has changed four times since yesterday. Here’s the latest from the NHC.

Latest Cones of Uncertainty for Marco and Laura

Houston is now only on the fringe of the cone of uncertainty for Marco.
Even though forecasts for Laura have been shifting steadily west, NHC now shows Houston outside the cone of uncertainty.

Note, however, the images above do not indicate the width of the storms, just their potential tracks up to five days out. The width of the cone indicates the degree of uncertainty about the track.

Tropical-storm-force winds extend outward up to 205 miles (335 km) from the center of Laura and 90 miles (150 km) from the center of Marco.

Intensity and Rainfall Predictions

Forecasters predicted Marco will become a hurricane tonight or Sunday, and remain at or near hurricane strength when it reaches the northern Gulf coast on Monday.

They also predict that Marco will dump 1 to 3 inches (isolated maximum amounts of 5 inches) on the Central U.S. Gulf Coast. This rainfall, they say, may result in areas of flash and urban flooding.

Tropical Storm Laura could bring additional rainfall and wind impacts by the middle of next week. This could result in a prolonged period of hazardous weather for areas affected by Marco.

Wind Predictions

We could feel the arrival of tropical storm force winds from Marco around mid-day on Monday.
Tropical storm force winds from Laura could be felt in Houston on Wednesday morning.
However, there’s only a 20-30% chance we will feel 40 mph winds from either Laura or Marco.

Rainfall and Flooding Predictions

At present, NOAA shows Marco dumping 2-6 inches of rain, mainly over the states east of us. (See below).

As of 4:50 EDT Saturday, NOAA is predicting less than an inch of rainfall for the Houston Area.

NOAA has not issued rainfall predictions yet for Laura. However, NOAA does give the Houston region a marginal (5%) chance of flash flooding from Marco.

As of 4:50 pm Saturday, NOAA predicts Houston has only a 5% chance of flash flooding from the storms.

Better Safe Than Sorry; How to Stay Up to Date

Forecasters for Laura emphasize that the second storm could result in a prolonged period of hazardous weather for areas affected by Marco.

NHC advises monitoring the progress of both storms several times a day until they pass. The NHC has started issuing updates every two to three hours for the duration of the storms.

Jeff Lindner, Harris County Meteorologist, warns, “While the situation for SE TX is looking better this afternoon, it would be important to maintain a close watch on this system in the event it weakens significantly and the system becomes more steered by the low level flow.” That could shift it back in the direction of Houston.

You can also sign up for text alerts from Ready Harris: Text MARCO to 888777 for emergency alerts. Better safe than sorry.

Posted by Bob Rehak on 8/22/2020

1089 Days since Hurricane Harvey