The National Weather Service (NWS) has launched a nationwide rollout of “experimental” flood forecasting maps. The maps show when, where and how much floodwaters will impact specific areas up to five days in advance.
System Already Rolled Out to Houston Area
NWS has already rolled out the system for Houston and East Texas with other parts of the county to follow.
The new system should enable emergency managers to see how predicted rainfall could impact structures, communities and people.
Until now, the best NWS could do was issue a flood watch or warning for communities. But the new maps will show how far floodwaters could spread in a community. That will help people better prepare for floods and evacuate from them. For instance, it will reportedly show when roads will be cut off by rising waters.
However, the new maps can’t yet forecast urban flash flooding related to lack of storm sewer capacity.
Near Real-Time View for Emergency Managers
NWS announced the new experimental flood maps on September 26, 2023. “These new services complement and support the issuance of flood watches and warnings by providing near-real-time, high-resolution, street-level visualizations showing where, when, and how much flood waters are forecast.”
David Vallee, director, Service Innovation and Partnership Division, NOAA’s National Water Center said, “These services will dramatically improve our ability to provide impact-based decision support services to our partners so they can preposition people and resources ahead of flood events.”
Three New Tools
Three new near-real-time services will help improve flood impact information. They include:
Hourly Analysis will model flood inundation extent based on streamflow analysis.
Posted by Bob Rehak on 10/16/23 based on information from NWS
2239 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/10/Screenshot-2023-10-16-at-1.34.08 PM-e1697481825151.png?fit=1100%2C614&ssl=16141100adminadmin2023-10-16 13:46:262023-10-16 17:26:46National Weather Service Rolling Out New Flood Warning Maps
Data provided by the National Weather Service (NWS) shows that precipitation appears to be increasing with temperature in Houston and Harris County. A reader recently asked whether there was a correlation. The hypothesis: in this climate, if temperature increases, then so will evaporation and rainfall. Eighty to 130 years worth of data at different locations show both variables trending up. But most scientists would consider the coefficient of correlation weak to non-existent.
Behind the Theory
The theory is plausible from several perspectives.
Warm air holds more moisture than cool air. Warm air also rises. As it cools at higher altitudes, precipitation forms. Think “afternoon thunderstorms on hot summer days.”
Precipitation also forms when warm and cool fronts collide.
It often forms when warm moisture-laden air streams in from the Gulf.
Hurricanes form in the hottest parts of the year.
But the question concerned correlation, not causation.
Other outside factors could reduce precipitation, such as droughts triggered by changes in Pacific Ocean currents. Those who remember the drought from 2011 to 2014 may also remember how hot it was.
But looking at 80 to 130 years of data highlights long-term climate trends. That “evens out” the influence of individual events.
NWS plotted all available historical data for precipitation and temperature on line graphs and then superimposed trend lines. The graphs show official data from two sources: Houston-Hobby Airport and the “City of Houston.”
I put City of Houston in quotes because the the official City-of-Houston data is currently collected at Bush Intercontinental Airport. But the location has bounced around. So the “City” isn’t one location, but many:
Cotton Station (July 1881 – September 1909)
Stewart Building at Preston and Fannin (September 1909 – February 1926)
Shell Building at Texas and Fannin (March 1926 – August 1938)
Federal Building at Franklin and Fannin (August 1938 – May 1969)
Intercontinental Airport (June 1969 – Present)
We have less data for Houston-Hobby because Hobby Airport didn’t exist until 1927. That’s when someone turned a 600-acre pasture into a landing field. The City of Houston purchased the field in 1937 and expanded it.
With those qualifiers, see the charts below. Both temperature and rainfall vary from year to year. But rainfall shows extreme variance. Regardless, in all four graphs the trend lines slowly increase.
City of Houston Data
The City of Houston data covers a wider time period. Within that, the location varied as noted above. The big jump was from downtown to Bush Intercontinental Airport in 1969. Generally speaking, as you go farther north from the coast, precipitation decreases. But the difference is less than an inch. Atlas 14 shows that a 100-year, 24-hour storm is 17.6 inches at Hobby, 17 inches downtown, and 16.9 inches at Intercontinental.
So the change in where the City collects official data actually worked against the hypothesis. And it shows.
Summary of Trend Differences
Summarizing the key differences:
As the temp trend line increased 4 degrees at Hobby, precipitation increased 9 inches.
As temp increased 4 degrees at various City locations, precipitation increased 6 inches.
Low Coefficient of Correlation
Jimmy Fowler of the National Weather Service’s Houston/Galveston office calculated the coefficients of correlation between the two series of data at each location.
For those who didn’t study statistics in college, the coefficient of correlation tells you how much one variable changes in response to another.
A perfect positive correlation is 1.0. Example: population growth and food consumption.
A perfect negative correlation is -1. Example: hours worked and free time.
In both cases, one unit of change in the first variable accounts for an equal unit of change in the second. But most correlations fall between the two extremes with different degrees of strength.
The chart below indicates how scientists would characterize correlation coefficients of .03 and .11. Both are considered “very weak” or having “no association.”
Fit of Trend Lines to Data
So, if the trends are all up, why is the co-efficient of correlation so low? Part of the answer has to do with those R2 (R squared) values you see at the bottom of the charts. They show the data doesn’t conform to the trend lines very well. Temperature fits moderately well. But precipitation shows extreme variance.
A perfect fit (1.0) would show all the data points on the line. As a rule of thumb, 0.8 (80%) or higher is considered a good fit. But the R2 values in these trend lines range from 0.03 to 0.5.
You can read into this data whatever you want depending on your point of view. Climate change advocates might see proof in the consistent slope of the trend lines that warming temperatures and more precipitation are related. A deeper dig into the data reveals the correlation is weak at best and possibly non-existent. Other factors may be at play and influencing the data.
To demonstrate causation, you need to show a directional relationship with no alternative explanations. But with weather, you have a multitude of alternative explanations.
Remember that weather is global and that we looked only at Houston in this instance.
However, a friend who traded weather-related derivatives before retirement tracked hundreds of temperature sites. He found they all trended warmer over time. But he believed the variance resulted primarily from changes in surrounding ground cover, i.e., replacement of natural ground cover with concrete – also known as the urban heat island effect.
He also tracked variance to changes in measurement locations (as with Houston).
Net: I find the similarities in the graphs interesting enough to keep digging. As my friend suggested, it would be interesting to find the coefficient of correlation between population growth and temperature change. I won’t leap to any generalizations at this point.
Posted by Bob Rehak on 12/30/2022with thanks to Jeff Lindner, Harris County Meteorologist and Jimmy Fowler of the National Weather Service.
1949 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/12/Hobby-Rainfall.png?fit=3144%2C2282&ssl=122823144adminadmin2022-12-30 17:24:042022-12-31 12:50:38Is Precipitation Increasing with Temperature?
The reason for the low risk has to do with a below-average rainfall pattern across much of Texas. The Texas Water Development board posted two stories in the Texas Water Newsroom last week about the potential for drought. Large parts of the state are already severely behind on rainfall for the year and the pattern is expected to continue through May when weakening La Niña conditions could return us to normal.
The map above shows that most of the Houston area has received about 90% of expected rainfall year to date. But large parts of the state have received less than 20%. TWDB predicts those dark areas on the map will expand at least through May. At that point, TWDB predicts only the extreme eastern part of the state will not be in some kind of drought condition.
Says Dr. Mark Wentzel, Texas Water Development Board Hydrologist, “The National Weather Service anticipates drought expansion across all but the eastern edge of the state by the end of May. Looking a little farther out there is some good news. La Niña conditions, that are at least partially responsible for drought in Texas, are expected to dissipate after April.”
So, the river flooding outlook could be very different by Hurricane season this year.
Did snow in February not help? Not really. Wentzel points out that snow is mostly air. It takes up to a foot of snow to equal and inch of rain.
Posted by Bob Rehak on 3/14/2021
1293 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/03/Screen-Shot-2021-03-14-at-3.57.49-PM.jpg?fit=1200%2C780&ssl=17801200adminadmin2021-03-14 16:54:292021-03-18 22:10:43NWS Says Chance of San Jacinto River Flooding in Next Three Months is Minor
As of 10:00 a.m. Monday morning, the National Hurricane Center (NHC) still shows the center of Tropical Storm Beta located offshore. The latest forecasts from the NHC predict that Beta will move onshore near Matagorda Bay, then move up the coastline toward League City.
The NHC also advises that the storm has picked up speed. Yesterday, they estimated 3 mph; today 7 mph.
No one seems to predict that the storm will intensify before landfall.
“Dry air continues to work into and wrap around the large wind field of Beta yielding the disorganized precipitation field with the system.”
Jeff Lindner, Harris County Meteorologist
Main Threat: Storm Surge
At this time, Beta’s main threat is to the coastline through storm surge. “Tides are currently running 4.0-4.5 feet in Clear Lake and across coastal sections of Harris County with several sites near the Gulf beaches running 4.0-4.5 feet. Coastal flooding is ongoing and will continue for much of the day. Several roadways are underwater along the coast and around Galveston Bay,” says Lindner.
Lindner continues, “As Beta makes landfall along the middle Texas coast later today, the storm will begin to slow and then turn ENE toward the upper TX coast. It will slowly weaken along the way. This track will keep onshore flow along the upper Texas coast tonight and Tuesday. Tides will remain high into the high tide tonight. Impacts along the coast will continue through the day and into tonight and likely Tuesday.”
The most likely arrival time of tropical storm force winds, if we get them, is later tonight.
Tropical storm force winds already cover a large part of the mid-Texas coast.
The storm will weaken as it moves toward the Houston Area and turn into a tropical depression. The further north you live from the coastline, the less intense winds will be.
Depending on where you live in Houston, you have a 30% to 100% chance of experiencing topical storm force winds. The Lake Houston Area is on the low end of that range. The National Weather Service predicts that the Lake Houston Area has a chance of seeing 39-57 mph winds. But Spaces City Weather advises that Beta is “not a significant wind threat.”
However, note that tropical-storm-force winds currently extend outward up to 175 miles (280 km) from the center of the storm.
Galveston has reported sustained winds of 39 mph and a gust of 43 mph during the past couple of hours.
Dry air has worked into the circulation of Beta, according to Lindner. “This has resulted in a more disorganized and scattered rainfall pattern. However, the system is still capable of heavy rainfall especially near the center later today and in bending structures east of the center for the next 48 hours.”
Models show several banding features developing during the next 48 hours over SE TX, But little consensus exists on where the heaviest rainfall totals may be.
Lindner advises that, “Given that much of the area will reside on the eastern side of a the tropical system, we should keep some level of concern of heavy rainfall and flooding in place through the next 48 hours.”
Lindner predicts that widespread rainfall amounts of 4-8 inches will be possible for areas along and south of I-10 with isolated totals of 10-12 inches under any training feeder bands. Totals to the north of I-10 will likely average 3-5 inches with isolated totals of 6-7 inches.
However, the NHC predicts slightly less rain. See the map below.
As long as the rainfall spreads out over the next 48 hours, most of the creeks and bayous can handle the expected rainfall amounts, Lindner says. But should any training develop, flash flooding would be possible.
Watches and Warnings in Effect
A Storm Surge Warning is in effect for Port Aransas, Texas to Rockefeller Wildlife Refuge, Louisiana. That includes Copano Bay, Aransas Bay, San Antonio Bay, Matagorda Bay, Galveston Bay, Sabine Lake, and Lake Calcasieu.
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
Lindner, the NHC and NWS all warn that tornadoes remain a threat with this storm. Especially, tonight and Tuesday.
Yesterday, models predicted that Beta would track up US59 toward the Humble/Kingwood Area. However, today, forecasters think the storm will track closer to the coast. They put it on a line toward League City.
Wind shear will keep Beta’s track close to the coastline, but it will also affect the cyclone’s intensity along with land interaction. The closer the cyclone stays near the Gulf of Mexico, the more likely that bands of convection containing tropical-storm-force winds will continue to roll onshore the Texas coast through 36-48 hours.
Flash, urban, and isolated minor river flooding is possible, but the danger is “slight.”
Net: Beta is still a threat. But it may be less of one than yesterday. That’s because of the dry air folding into the system and wind sheer which seem to be weakening it somewhat. Be hopeful, but cautious. Expect several inches of rain and high winds in the next two days with both tapering off Wednesday.
Posted by Bob Rehak on 9/21/2020 at noon based on data from NHC, NWS, Jeff Lindner, Space City Weather and Weather Live
1119 Days after Hurricane Harvey and 368 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/09/Screenshot-2020-09-21-at-11.37.19-AM-scaled.jpg?fit=1183%2C2560&ssl=125601183adminadmin2020-09-21 11:46:032020-09-21 11:52:04Beta Moving Ashore Today Then Likely Tracking Slightly South of Houston
After a week of worry! After adrenaline-fueled prep for two back-to-back hurricanes that could have wreaked havoc on Houston…I woke up refreshed this morning, walked to my weather window, and saw…nothing unusual. What happened? I checked my weather gauge. It read 0.00 inches of rain. Max winds since midnight: 3 mph.
It would appear the Houston Area dodged Laura’s silver bullet. But why? According to Harris County Meteorologist, Jeff Linder, two things spared us the wrath of Laura. First, Laura shifted slightly east. Second, as Laura intensified, the wind field pulled in tighter. That diminished feeder bands on the western side of the storm.
How Close Laura Came
Here are some radar and satellite images that show how close the storm came.
The shot above and the radar loop below show dramatically how the storm shifted east last night. The National Hurricane Center had predicted eye of the storm to move up the Sabine River near Port Arthur, about 40 miles west.
HURRICANE CONDITIONS SPREADING FARTHER INLAND ACROSS SOUTHWESTERN LOUISIANA…
CATASTROPHIC STORM SURGE, HURRICANE FORCE WINDS, AND FLASH FLOODING WILL CONTINUE THIS MORNING…
Fort Polk, Louisiana recently reported a sustained wind of 45 mph (72 km/h) and a wind gust of 70 mph (113 km/h). SUMMARY OF 600 AM CDT…1100 UTC…
LOCATION…30.9N 93.3W ABOUT 55 MI…90 KM N OF LAKE CHARLES LOUISIANA
MAXIMUM SUSTAINED WINDS…105 MPH…170 KM/H
PRESENT MOVEMENT…N OR 355 DEGREES AT 15 MPH…24 KM/H
MINIMUM CENTRAL PRESSURE…964 MB…28.47 INCHES
After Hurricane Rita, which dodged Houston like Laura, I coined a term called “hurricane guilt.” It’s that feeling of elation you get when you realize the storm missed you…followed closely by the realization that it destroyed innocent lives elsewhere.
That’s what I feel right now. As I write this, the sun is rising and birds are singing. Soon images of Laura’s destruction will start to pour in. Only then will we know how lucky we were.
Posted by Bob Rehak at 6:45 am on 8/27/2020 based on information from NWS, NHC, RadarScope, and Jeff Lindner, Harris County Meteorologist
1094 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/Laura-Wide-Shot-scaled.jpg?fit=1183%2C2560&ssl=125601183adminadmin2020-08-27 06:54:342020-08-27 07:33:07How Close Was Laura?
Many people mistake the cone of uncertainty associated with a hurricane as the width of a storm. It’s not. It merely shows likely paths the hurricane’s eye could take as it comes ashore. There’s an equal probability of any path within the cone. Cones expand with more distant projections because uncertainty increases. But as forecasters always warn us, the impact of a major hurricane extends far beyond the cone of uncertainty.
Compare these two pictures to fully understand the difference.
I have arbitrarily assigned the term “impact corridor” to the area between the two lines to help describe the difference. (No one uses this term but me, although they probably should.)
Of course, as you go further from the center of the storm, the intensity decreases and so do negative impacts.
Currently (12:30 pm CDT, 8/26/2020), hurricane-force winds extend outward up to 70 miles from the center and tropical-storm-force winds extend outward up to 175 miles. That’s 350 miles across!
Each year, an average of ten tropical storms develop over the Atlantic Ocean, Carribean Sea, and Gulf of Mexico. Many of these remain over the ocean. Six of these storms become hurricanes each year. In an average 3-year period, roughly five hurricanes strike the United States coastline, killing approximately 50 to 100 people anywhere from Texas to Maine. Of these, two are typically major hurricanes (winds greater than 110 mph).
Typical hurricanes are about 300 miles wide although they can vary considerably in size.
The eye at a hurricane’s center is a relatively calm, clear area approximately 20-40 miles across.
The eyewall surrounding the eye is composed of dense clouds that contain the highest winds in the storm.
The storm’s outer rainbands (often with hurricane or tropical storm-force winds) are made up of dense bands of thunderstorms ranging from a few miles to tens of miles wide and 50 to 300 miles long.
Hurricane-force winds can extend outward to about 25 miles in a small hurricane and to more than 150 miles for a large one. Tropical storm-force winds can stretch out as far as 300 miles from center of a large hurricane.
Frequently, the right side of a hurricane is the most dangerous in terms of storm surge, winds, and tornadoes.
A hurricane’s speed and path depend on complex ocean and atmospheric interactions, including the presence or absence of other weather patterns. This complexity of the flow makes it very difficult to predict the speed and direction of a hurricane.
Do not focus on the eye or the track. Hurricanes are immense systems that can move in complex patterns that are difficult to predict. Be prepared for changes in size, intensity, speed and direction.
1. The first condition is that ocean waters must be above 79 degrees Fahrenheit. Below this threshold temperature, hurricanes will not form or will weaken rapidly. Ocean temperatures in the tropics routinely surpass this threshold.
3. The third ingredient is that of a saturated lapse rate gradient near the center of rotation of the storm. A saturated lapse rate insures latent heat will be released at a maximum rate. Hurricanes are warm core storms. The heat hurricanes generate is from the condensation of water vapor as it convectively rises around the eye wall. The lapse rate must be unstable around the eyewall to insure rising parcels of air will continue to rise and condense water vapor.
4. The fourth and one of the most important ingredients is that of a low vertical wind shear, especially in the upper level of the atmosphere. Wind shear is a change in wind speed with height. Strong upper level winds destroy the storms structure by displacing the warm temperatures above the eye and limiting the vertical accent of air parcels. Hurricanes will not form when the upper level winds are too strong.
5. The fifth ingredient is high relative humidity values from the surface to the mid levels of the atmosphere. Dry air in the mid levels of the atmosphere impedes hurricane development in two ways. First, dry air causes evaporation of liquid water. Since evaporation is a cooling process, it reduces the warm core structure of the hurricane and limits vertical development of convection. Second, dry air in the mid levels can create what is known as a trade wind inversion. This inversion is similar to sinking air in a high pressure system. The trade wind inversion produces a layer of warm temperatures and dryness in the mid levels of the atmosphere due to the sinking and adiabatic warming of the mid level air. This inhibits deep convection and produces a stable lapse rate.
6. The sixth ingredient is that of a tropical wave. Often hurricanes in the Atlantic begin as a thunderstorm complex that moves off the coast of Africa. It becomes what is known as a midtropospheric wave. If this wave encounters favorable conditions such as stated in the first five ingredients, it will amplify and evolve into a tropical storm or hurricane. Hurricanes in the East Pacific can develop by a midtropospheric wave or by what is known as a monsoonal trough.
Posted by Bob Rehak on 8/26/2020 based on data from Weather.gov.
1093 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/Laura-In-Gulf-W-Red-Lines.jpg?fit=1000%2C1000&ssl=110001000adminadmin2020-08-26 12:53:252020-08-26 12:53:39Impact Corridor of Hurricanes Much Wider than Cone of Uncertainty
For the Lake Houston Area, NWS predicts potential for moderate flooding rain
Potential Impacts Include:
Moderate rainfall flooding may prompt several evacuations and rescues.
Rivers and tributaries may quickly become swollen with swifter currents and overspill their banks in a few places, especially in usually vulnerable spots. Small streams, creeks, canals, and ditches overflow.
Flood waters can enter some structures or weaken foundations. Several places may experience expanded areas of rapid inundation at underpasses, low-lying spots, and poor drainage areas. Some streets and parking lots take on moving water as storm drains and retention ponds overflow. Driving conditions become hazardous. Some road and bridge closures.
For Lake Houston Area, NWS Predicts Winds from 58 to 73 mph
Potential Impacts Include:
Some damage to roofing and siding materials, along with damage to porches, awnings, carports, and sheds. A few buildings experiencing window, door, and garage door failures. Mobile homes damaged, especially if unanchored. Unsecured lightweight objects become dangerous projectiles.
Several large trees snapped or uprooted, but with greater numbers in places where trees are shallow rooted. Several fences and roadway signs blown over.
Some roads impassable from large debris, and more within urban or heavily wooded places. A few bridges, causeways, and access routes impassable.
Scattered power and communications outages, but more prevalent in areas with above ground lines.
…TROPICAL STORM WARNING REMAINS IN EFFECT…
West of Lake Houston, the threat level decreases. Between Dayton and Liberty, it increases.
For those closer to the coast, the map also includes storm surge warnings. Also check out the estimates of tornado threats.
The latest satellite images show Laura just off the coast. The storm is moving north at about 15 miles per hour.
No Lake Conroe Release Anticipated Before Storm
In other hurricane related news, the SJRA just issued a press release stating that:
“SJRA is operating under standard protocols for a severe weather event and will be onsite at Lake Conroe throughout the night and into Thursday. Lake Conroe remains about 15 inches low, and based on the current forecast, no reservoir releases are expected.“
Posted by Bob Rehak on 8/26/2020 at 11:00 a.m. based on estimates from the National Weather Service.
1093 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-26-at-10.27.36-AM.png?fit=2078%2C1560&ssl=115602078adminadmin2020-08-26 11:03:432020-08-26 11:24:55NWS Predicts Local Impacts to Lake Houston Area from Hurricane Laura
Extremely dangerous hurricane will make landfall near Sabine Pass tonight with catastrophic impacts.
All preparations must be completed by 6:00 p.m. this evening.
Conditions will begin to deteriorate late this afternoon and evening over the region.
Rainfall predictions for the Lake Houston Area increased overnight. We could now receive up to six inches.
Laura became a large and dangerous hurricane overnight with expansion of the wind field. USAF missions indicate the central pressure continues to fall. Winds are increasing. And Laura has experienced a 40 knot increase in winds in the last 24 hours. (A knot = 1.15 mph.) The eye of the hurricane is starting to clear out. Further rapid intensification is likely today.
The center of Laura should cross the coast near Sabine Pass, TX, near the Texas/Louisiana Border. Models have tightly clustered just either side of the state line. There is high confidence that Laura will make landfall in the areas between Sea Rim State Park and Cameron LA early Thursday morning. The hurricane should move rapidly northward, up the Sabine River Valley on Thursday.
Given the fast forward motion, significant wind impacts will extend well inland along the track of Laura with wind damage likely extending 100-200 miles inland over eastern Texas and western Louisiana.
Hurricane force winds extend outward 70 miles from the center and tropical storm force winds 175 miles.
Expect a catastrophic storm surge event over extreme SE TX and much of coastal Louisiana.
Strong north winds tonight may drive water levels along the north side of Galveston Island and Bolivar to elevated levels and water levels in the NW part of Galveston Bay may fall well below normal.
The following values are above ground level:
Galveston Bay: 1-3 ft
Bolivar: 2-5 ft
High Island to Sea Rim State Park: 6-9 ft
Sea Rim State Park to Intracoastal City (Including Beaumont and Lake Charles): 10-15 ft.
Large destructive waves will accompany storm surge.
West of I-45: 30-40mph
East of I-45: 45-55mph
Chambers, Liberty, Polk Counties: 50-65mph
Jefferson, Orange Counties and Lake Charles: 110-120mph
Higher gusts will occur in squalls.
Hurricane-force winds currently extend outward up to 70 miles from the center and tropical-storm- force winds extend outward up to 175 miles.
The Harris County line is 75 miles from Sabine Pass; Lake Houston 80 miles.
West of I-45: 1-2 inches
East of I-45: 2-6 inches, isolated totals up to 8 inches.
Sabine River Valley: 8-12 inches
Overnight, rainfall predictions for the Lake Houston Area increased 2 inches. The six inches now predicted roughly equals the amount of rain the Lake Houston Area received on May 7th last year. Elm Grove residents: Please note: the volume of detention ponds now on Woodridge Village should be enough to protect you unless there is a design flaw.
The main rainfall threat comes from rapid, intense rains which can cause street flooding.
Complete all preparations by 6:00 pm this evening. Earlier the better.
If in evacuation areas, evacuate immediately…especially in the Beaumont and Lake Charles area.
Lake Houston as of 6:30 a.m. was at 41.17 feet (full pool 42.4). The Coastal Water Authority will continue releasing water from Lake Houston until it reaches 41 feet.
Lake Conroe is not releasing water and stands at 199.72 feet (full pool is 201).
For More Up-to-the-Minute Information
For the most up-to-date rainfall totals and water levels in bayous, creeks, and rivers, visit www.harriscountyfws.org. This system relies on a network of gage stations that have been strategically placed throughout Harris and surrounding counties.
Posted by Bob Rehak at 7:12 a.m. on 8/26/2020 based on input from the National Hurricane Center and Jeff Lindner, Harris County Meteorologist.
1093 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/091953WPCQPF_sm.gif?fit=892%2C716&ssl=1716892adminadmin2020-08-26 07:18:322020-08-26 08:46:51As of 7 a.m., Laura Predicted to Make Landfall at Sabine Pass as Cat 4 Hurricane
These warnings were just issued by Jeff Lindner, Harris County Meteorologist, the National Hurricane Center, and City of Houston:
Hurricane warnings issued from San Luis Pass into Louisiana.
Landfall of a devastating hurricane likely between Galveston Bay and Sabine Pass tomorrow night.
Rush to complete preparations to protect life and property.
Heed all evacuation recommendations.
Laura – now a hurricane with sustained winds of 75mph – is continuing to intensify. The hurricane will likely rapidly intensify over the next 24-36 hours, right up to landfall along the upper TX coast. The National Hurricane Center predicts Laura will become a major hurricane with sustained winds over 110 mph by tomorrow night or early Thursday morning when it makes landfall somewhere between Galveston Bay and Sabine Pass.
Everyone should be planning for the landfall of a very serious hurricane between Galveston Bay and Sabine Pass on the Louisiana border. Additional shifts in the track are possible that could bring the core of Laura into Galveston Bay and Harris/Galveston Counties.
The large wind field will result in strong winds likely 100-150 miles inland across east Texas.
Prepare for power outages extending well inland along with significant wind damage and extended outages.
Prepare for the impact of a major hurricane (cat 3 or higher). Once the inner core of Laura forms, significant intensification is likely, and conditions look very favorable for intensification.
Tropical Storm force winds will begin along the coast at around 8:00 pm Wednesday evening.
Advice from City, Lake Status
“Rainfall amounts in the Lake Houston Watershed over the next six days are expected to be 2 – 4 inches with isolated accumulation of 6 inches possible,” said Dave Martin. “Currently, the Lake Houston Watershed is dry and the projected impact to our area will be to our east with the largest possible impact expected along the East Fork of the San Jacinto River. Lake Houston is already down one foot from normal pool with the possibility of being lowered additionally, if necessary. Please make sure all property along the shoreline is secured in the event additional lowering is ordered.”
“Regardless of where this storm lands,” said Martin, “it is important all residents prepare themselves and have a plan. Hurricane Laura will likely be similar to Ike with severe wind impacts and power outages. The City of Houston has prepared resources to help you get ready for upcoming disasters and make sure you are prepared for this one. Please visit www.readyhoustontx.gov to learn more.
Prepare for the landfall of a major hurricane along the SE TX coast
Bring in anything in your yard, such as lawn furniture, that could become airborne.
All preparations will be to be competed by 6:00 p.m. Wednesday evening.
Posted by Bob Rehak on 8/24/2020 based on input from the National Hurricane Center and Jeff Lindner, Harris County Meteorologist.
1091 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/153403_earliest_reasonable_toa_no_wsp_34.png?fit=897%2C736&ssl=1736897adminadmin2020-08-25 12:30:512020-08-25 12:31:07Laura Intensifying into Major Hurricane; Prepare for Big Winds, Power Outages
Overnight, Laura turned into a hurricane. At 5:25 this morning, Jeff Lindner, Harris County Meteorologist, issued the following:
Hurricane Watches extended west to San Luis Pass…now include Harris and Galveston Counties
Major hurricane forecast in the NW Gulf of Mexico Wednesday
Enact hurricane plans now. Follow all recommendations from local officials.
At 7:00 a.m., he issued another warning saying that:
Laura upgraded to a hurricane…intensification will continue through landfall.
Mandatory evacuation order for Galveston Island effective immediately.
Laura is now over the SE Gulf of Mexico and moving toward the WNW after having jogged westward overnight. Deep convection has developed over and near the center this morning. Some light northerly system continues to impact Laura, which continues to track to the south of predictions.
The steering pattern that will bring Laura to the NW Gulf of Mexico remains somewhat in flux this morning. Laura will turn northwest and then north. But uncertainty remains as to when Laura will make this turn. Overnight model guidance now delays this turn a little longer and brings Laura more toward the upper Texas coast. NHC may have to shift their forecast track a bit more westward later this morning.
Tropical storm force winds will begin to arrive along the coast Wednesday evening and spread inland Wednesday night into Thursday morning.
A central core is starting to form with Laura and overall circulation of the system is looking better defined. Conditions in the central Gulf today favor a period of rapid intensification. Laura is forecast to make landfall as a major hurricane along the SE TX/SW LA coast late Wednesday.
Laura is a fairly large storm and impacts will be far reaching from the impact point extending both west and east.
Tropical-storm-force winds currently extend outward up to 175 miles (280 km) from the center.
Will rainfall forecast at 2-4 inches east of I-45 and 1-3 inches west of I-45, but this may need to be increased later today. WPC has placed areas east of I-45 in a slight risk for flash flooding.
Still looking at 2-4 feet above ground level in Galveston Bay and 4-6 feet on Bolivar with levels of 7-11 feet east of High Island into Louisiana. Should the track shift more west, these values around Galveston Bay would potentially need to be increased significantly.
Tropical storm force winds will be moving into the area Wednesday evening. Expect winds of 40-50mph across Harris County northward along I-45 with hurricane conditions becoming increasingly likely over Liberty and Chambers Counties. Any additional shift westward in the track will bring stronger winds across the area.
Be prepared for power outages starting Wednesday evening.
Enact hurricane plans now.
Follow all recommendation on evacuation from local officials.
Storm Surge Watch is in effect for San Luis Pass Texas to Ocean Springs Mississippi.
High Island TX to Morgan City LA including Sabine Lake, Calcasieu Lake, and Vermilion Bay…7-11 ft
Port Bolivar TX to High Island TX…4-6 ft
San Luis Pass TX to Port Bolivar TX…2-4 ft
Galveston Bay…2-4 ft
Hurricane Watch is in effect for San Luis Pass Texas to west of Morgan City Louisiana
Tropical Storm Watch is in effect for…
San Luis Pass to Freeport Texas
Morgan City Louisiana to the Mouth of the Mississippi River
A Storm Surge Watch means there is a possibility of life-threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours.
A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous.
Posted by Bob Rehak on 8/25/2020 with input from CoH, Harris County, National Hurricane Center, National Weather Service, and ReadyHarris.
1092 Days After Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/08/093605_peak_surge.png?fit=897%2C736&ssl=1736897adminadmin2020-08-25 08:43:282020-08-25 15:01:42Laura Upgraded to Hurricane; Will Intensify Through Landfall; Mandatory Evacuation for Galveston Island