Models point to the area from US59 to about 40 miles northwest of Lake Houston as the area of greatest risk for heavy rainfall.
Isolated areas could reach higher than 7″ instead of up to 7″.
Watersheds on the northern and northeast sides of the county are at greatest risk for flooding according to overnight modeling of different rain scenarios by Harris County Flood Control.
Here’s where things stand as of noon on Monday, 3/21/2022.
Severe Weather Risk from Tonight into Early Tuesday.
Gulf moisture quickly returned to the region overnight. Scattered light showers are moving quickly from south to north. An upper level storm system is approaching from West Texas with strong lift ahead of it. Conditions will favor strong to severe thunderstorms in our area by mid to late afternoon over the warm air mass.
All of north Houston falls into the “enhanced risk” area for severe weather tonight. Updated at mid-day.
All of north Houston falls into the “enhanced risk” area for severe weather tonight.
The National Weather Service does not assign a mathematical probability to the definition of Enhanced Risk, but note that it is the mid-point (3) on a 5-point scale.
Tornados may form, especially in any supercells that may form in this area. The Brazos Valley area will see the highest tornado threat, according to Lindner. But the National Weather Service Storm Prediction Center extends the area of 10% risk to the entire north and northeast Houston area. Large hail and damaging winds will also be possible with these storms.
The NWS Storm Prediction Center (SPC) gives a large part of Texas a 10% chance for tornadoes tonight.An even higher risk area is NW of Houston.
The SPC also gives a 30% chance of large hail and damaging winds to west, north and northeast Houston.
The worst large-hail probabilities are west of us, but our area still has a 30% probability.
Severe Threat Gives Way to Heavy Rainfall Threat During Night
According to Lindner, the severe threat will gradually transition to a heavy rainfall threat during the night as the pre-frontal trough slows over the Houston area. Formation of a line or two of training thunderstorms will be possible. Models point toward the US 59 corridor northeast of Houston and about 40 miles to the northwest as the most likely area of cell training.
The red area indicates a 40% chance of excessive rainfall.It includes areas from the northwest side of Houston east to roughly US59 and the Lake Houston Area.Updated 7:30am.
Lindner predicts rainfall amounts of 2-4 inches north of I-10 with isolated totals upwards of 6-7 inches. South of I-10, amounts of 1-2 inches look most likely. Given moisture levels, hourly rainfall rates of 2-3 inches per hour will be possible. Street flooding in urban areas is currently the greatest threat and the Tuesday morning commute may be impacted.
Runoff, River and Stream Report
While grounds are generally dry over the area, expected rainfall rates in short duration will generate rapid run-off. Rises on all creeks and bayous are expected tonight.
HCFCD modeled various contingency forecasts yesterday afternoon with different rainfall durations and amounts to see how area bayous and creeks would respond.
Most of the creeks and bayous will be able to handle 4-5 inches of rainfall in a 4-6 hour period or longer. Should parts of the area realize the higher isolated totals of 6-7 inches, there would likely be some concerns for channels reaching bankfull.
While uncertainty still exists on exactly where training lines will form, Lindner believes watersheds on the northern and northeastern sides of Harris County will be at greatest risk. He named:
Cedar Bayou
Luce Bayou
East and West Forks of the San Jacinto River
Cypress Creek
Spring Creek
Greens Bayou
Halls Bayou
Little Cypress Creek
Willow Creek
These watersheds will likely see some of the higher rainfall amounts and responses.
To view real-time stream levels and inundation reports, visit the Harris County Flood Warning System and click on a gage near you. Stay home tonight. Don’t roam. Let your fingers do the slogging.
Severe Weather, Flash Flood Likelihood Increasing for Monday Afternoon into Early Tuesday
Updated at 7:30 PM:
According to Jeff Lindner, Harris County Meteorologist, a powerful storm will move into Texas over the next 24 hours bringing multiple hazards to the area. The chances of severe weather and heavy rainfall by Monday afternoon and evening continue to increase. They are also expanding over a wider area. Since the original post, Harris County’s Meteorologist, Jeff Lindner has raised concerns about rises on the San Jacinto River West and East Forks to flood stage over the next few days. Rises on other creeks and bayous in Harris County also look likely, especially where we experience cell training and higher rainfall totals. Lindner advises to monitor weather closely on Monday and Monday night.
Outlook tomorrow for severe weather from the NWS Storm Prediction Center.
Higher Likelihood of Severe Weather Including Tornados Starting Monday Afternoon
There were some doubts yesterday about the likelihood for supercells to develop. But as we get closer to the storm’s arrival and certainty increases, supercell formation looks increasingly likely. “All severe modes will be in play including tornadoes, large hail, and damaging winds,” says Lindner. “There could be a few strong tornadoes, especially for locations north of I-10.” Yesterday, the main likelihood was north of SH105.
The National Weather Service Storm Prediction Center has expanded the enhanced risk (3 out of 5) outline to include more of Southeast Texas. The severe threat will begin in the mid-afternoon hours on Monday and continue into the late evening hours.
6-7 Inches, Flash Flooding Possible
While the heaviest rainfall will likely occur over North Texas, the potential for high-precipitation supercells to develop and train across Southeast Texas is increasing for Monday afternoon and evening. As the front slows over Southeast Texas Monday night, Lindner expects the severe threat to gradually shift toward heavy rainfall and possible flash flooding throughout the night.
The greatest threat will generally be along and north of I-10. A slow-moving line of supercells will raise the flash-flood threat. If you get caught under one that’s training across your area as we saw back in January, be prepared.
Lindner has virtually doubled his rainfall predictions since yesterday. Instead of widespread 0.5-2 inches across the area, he now sees widespread 3-4 inches. And whereas yesterday he saw isolated rainfall totals up to 4 inches, today he estimates up to 6-7 inches.
Hourly rainfall rates of 2-3 inches will be possible leading to rapid onset flash flooding over urban areas. Street flooding will be the primary threat, but under corridors of excessive rainfall, significant rises on creeks and bayous will be possible.
Jeff Lindner, Harris County Meteorologist
In an update at 7:30 PM Sunday night, Lindner specifically mentioned the possibility of the East and West Forks of the San Jacinto rising to flood stage if we receive the higher rainfall totals in the forecast.
The NWS Weather Prediction Center has upgraded the area north of the I-10 corridor to a moderate risk for flash flooding.
National Weather Service outlook tomorrow for excessive rainfall.
Monday afternoon and evening will be active over the area. So have multiple ways to receive warnings.Make sure you have fresh batteries in your weather radio and flashlights; it could be a long night.
Putting Forecast in Perspective
To put this in perspective:
The supercells that spawned tornadoes over Kingwood in January dumped approximately 5 inches of rain. I talked with a lady on Facebook this morning whose home was destroyed by a tornado in that storm. She said she received warnings seconds before the tornado struck. She barely had enough time to get to an interior hallway before her home started crumbling around her.
The May 7th, 2019, storm that flooded more than 200 homes in Elm Grove dumped 7 inches of rain. But less than 20% of the floodwater detention capacity on Woodridge Village had been built at that point.
The City announced at 5:15 this afternoon that it will lower Lake Houston by 1 foot starting tonight. A forecast greater than 3 inches triggers the Lake Houston lowering protocol.
How To Get Warnings
NOAA broadcasts warnings on weather radio in a continuous loop during emergencies.
USGS has a web app called Water On the Go that shows water elevations at flood gages wherever you go in Texas.
Harris County Flood Control District’s Storm Center can connect you to a wide variety of preparedness articles and ways to summon help in an emergency.
A number of companies offer good apps for cell phones that offer warnings. I especially like one called Dark Skies that bills itself as “hyper-local” weather. It frequently tells me to the minute when a storm will arrive at my exact location…wherever I am.
You can also find links to dozens of other weather related apps and sites on my Links Page. Check them out before the storm arrives. You never know when a storm will knock out a web site, a cell tower, or power. So be prepared with multiple backups.
Posted by Bob Rehak on 3/20/2022based on input from the NWS, HCFCD and City of Houston
1664 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/03/image001.gif?fit=815%2C555&ssl=1555815adminadmin2022-03-20 16:05:352022-03-20 20:54:09Severe Weather Threat Increasing for Tomorrow, Up to 7″ Now Possible
I received an email from Jeff Lindner, Harris County’s meteorologist, around 1PM today that warned of possible severe weather from next Monday afternoon into early Tuesday Morning. As I explored it more, I also came across a fascinating academic study about the communication of weather risk that you may want to share with friends and relatives. One of the key findings: mobile home owners may need more response time than typical tornado warnings provide.
Possible Tornados, Hail, Damaging Winds, Street Flooding Early Next Week
“All severe modes will be in play Monday afternoon and evening including tornadoes, large hail, and damaging winds. The tornado threat appears highest north of HWY 105. The severe threat will be lowest near the coast and around Matagorda Bay,” said Lindner. “Heavy rainfall is also becoming an increasing concern.”
While most models show from one half to two inches of rain around Bush Intercontinental Airport, one model predicts four inches. Lindner predicts 1-2 inches of widespread rain north of I-10 with isolated totals of 3-4 inches possible. South of I-10 rainfall amounts of .50-1.0 inch will be possible.
“Given the dry grounds in place, some of this rainfall will soak in,” says Lindner. “But potential for high hourly rainfall rates poses an urban street flooding threat.” In other words, rain may fall faster than it can soak in or drain off, and then collect in streets.
NWS Cites Conditions Favorable for Supercell Formation
The NWS Storm Prediction Center contains a wealth of information for weather aficionados including academic publications on meteorology. Mindful of how a January tornado struck Kingwood at 1:30AM and also how the Lake Conroe release during Harvey arrived in the middle of the night, the following study caught my eye:
All researchers work in Norman, Oklahoma. They studied what time of day the public was least confident about receiving and responding to tornado warnings. Answer: between midnight and 4:00AM. Not a big surprise there. Most people are sleeping then. But the authors also studied several related questions:
Where do most overnight tornados take place?
Who is most at risk?
How and when can you best communicate that risk to protect lives?
Percent “very” or “extremely” confident in their ability to respond to a tornado warning by time of day. Shading indicates the 95% confidence level.
Findings
The authors found the southeastern portion of the US most susceptible to nocturnal tornadoes. East Texas is on the edge of the highest risk area. They also found that:
People’s confidence in their ability to receive warnings is lowest when the risk is highest for these storms.
The Southeast has a high rate of mobile home ownership, but mobile home owners don’t always perceive that they have higher risk, a perception that makes them especially vulnerable to tragic outcomes during nocturnal tornado events.
The number of weather resources that an individual had access to affected weather awareness and preparedness more than any demographic characteristics.
Forecasters and communicators should continue to emphasize the use of multiple forms of communication. They suggest “weather radios, cell phone apps, Wireless Emergency Alerts, and other forms of passive notification systems. Increased use of these tools will ultimately increase the likelihood of someone receiving warning information while they are asleep or otherwise occupied.”
The challenges of nocturnal tornadoes cannot be addressed if residents do not receive forecasts or warnings in the first place.
People will take action not just on forecasts, but their personal perception of risk. More communication about the degree of risk may help people make better decisions.
Forecasters should communicate the degree of risk before 10PM so that people can prepare severe weather plans before they go to sleep.
People in mobile housing need more response time than typical tornado warnings provide.
These findings should help inform forecasters and emergency managers about communities that need more time to respond to overnight tornado events. In the meantime, change the battery in that old weather radio! It’s springtime in Texas.
Posted by Bob Rehak on 3/19/2022
1663 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/03/Screen-Shot-2022-03-19-at-2.47.22-PM.png?fit=2096%2C1168&ssl=111682096adminadmin2022-03-19 16:07:072022-03-19 16:16:33Severe Weather Predicted Next Monday into Tuesday
Flood Watch Starting 7PM Tonight
Jeff Lindner, Harris County Meteorologist, has released another update on the approaching storm. Not much has changed since last night except that:
Here’s where things stand as of noon on Monday, 3/21/2022.
Severe Weather Risk from Tonight into Early Tuesday.
Gulf moisture quickly returned to the region overnight. Scattered light showers are moving quickly from south to north. An upper level storm system is approaching from West Texas with strong lift ahead of it. Conditions will favor strong to severe thunderstorms in our area by mid to late afternoon over the warm air mass.
The National Weather Service does not assign a mathematical probability to the definition of Enhanced Risk, but note that it is the mid-point (3) on a 5-point scale.
Tornados may form, especially in any supercells that may form in this area. The Brazos Valley area will see the highest tornado threat, according to Lindner. But the National Weather Service Storm Prediction Center extends the area of 10% risk to the entire north and northeast Houston area. Large hail and damaging winds will also be possible with these storms.
The SPC also gives a 30% chance of large hail and damaging winds to west, north and northeast Houston.
Severe Threat Gives Way to Heavy Rainfall Threat During Night
According to Lindner, the severe threat will gradually transition to a heavy rainfall threat during the night as the pre-frontal trough slows over the Houston area. Formation of a line or two of training thunderstorms will be possible. Models point toward the US 59 corridor northeast of Houston and about 40 miles to the northwest as the most likely area of cell training.
Lindner predicts rainfall amounts of 2-4 inches north of I-10 with isolated totals upwards of 6-7 inches. South of I-10, amounts of 1-2 inches look most likely. Given moisture levels, hourly rainfall rates of 2-3 inches per hour will be possible. Street flooding in urban areas is currently the greatest threat and the Tuesday morning commute may be impacted.
Runoff, River and Stream Report
While grounds are generally dry over the area, expected rainfall rates in short duration will generate rapid run-off. Rises on all creeks and bayous are expected tonight.
HCFCD modeled various contingency forecasts yesterday afternoon with different rainfall durations and amounts to see how area bayous and creeks would respond.
Most of the creeks and bayous will be able to handle 4-5 inches of rainfall in a 4-6 hour period or longer. Should parts of the area realize the higher isolated totals of 6-7 inches, there would likely be some concerns for channels reaching bankfull.
While uncertainty still exists on exactly where training lines will form, Lindner believes watersheds on the northern and northeastern sides of Harris County will be at greatest risk. He named:
These watersheds will likely see some of the higher rainfall amounts and responses.
To view real-time stream levels and inundation reports, visit the Harris County Flood Warning System and click on a gage near you. Stay home tonight. Don’t roam. Let your fingers do the slogging.
Posted by Bob Rehak at 12:30 PM on 3/21/22
1665 Days since Hurricane Harvey
Severe Weather Threat Increasing for Tomorrow, Up to 7″ Now Possible
Severe Weather, Flash Flood Likelihood Increasing for Monday Afternoon into Early Tuesday
Updated at 7:30 PM:
According to Jeff Lindner, Harris County Meteorologist, a powerful storm will move into Texas over the next 24 hours bringing multiple hazards to the area. The chances of severe weather and heavy rainfall by Monday afternoon and evening continue to increase. They are also expanding over a wider area. Since the original post, Harris County’s Meteorologist, Jeff Lindner has raised concerns about rises on the San Jacinto River West and East Forks to flood stage over the next few days. Rises on other creeks and bayous in Harris County also look likely, especially where we experience cell training and higher rainfall totals. Lindner advises to monitor weather closely on Monday and Monday night.
Higher Likelihood of Severe Weather Including Tornados Starting Monday Afternoon
There were some doubts yesterday about the likelihood for supercells to develop. But as we get closer to the storm’s arrival and certainty increases, supercell formation looks increasingly likely. “All severe modes will be in play including tornadoes, large hail, and damaging winds,” says Lindner. “There could be a few strong tornadoes, especially for locations north of I-10.” Yesterday, the main likelihood was north of SH105.
The National Weather Service Storm Prediction Center has expanded the enhanced risk (3 out of 5) outline to include more of Southeast Texas. The severe threat will begin in the mid-afternoon hours on Monday and continue into the late evening hours.
6-7 Inches, Flash Flooding Possible
While the heaviest rainfall will likely occur over North Texas, the potential for high-precipitation supercells to develop and train across Southeast Texas is increasing for Monday afternoon and evening. As the front slows over Southeast Texas Monday night, Lindner expects the severe threat to gradually shift toward heavy rainfall and possible flash flooding throughout the night.
The greatest threat will generally be along and north of I-10. A slow-moving line of supercells will raise the flash-flood threat. If you get caught under one that’s training across your area as we saw back in January, be prepared.
Lindner has virtually doubled his rainfall predictions since yesterday. Instead of widespread 0.5-2 inches across the area, he now sees widespread 3-4 inches. And whereas yesterday he saw isolated rainfall totals up to 4 inches, today he estimates up to 6-7 inches.
In an update at 7:30 PM Sunday night, Lindner specifically mentioned the possibility of the East and West Forks of the San Jacinto rising to flood stage if we receive the higher rainfall totals in the forecast.
The NWS Weather Prediction Center has upgraded the area north of the I-10 corridor to a moderate risk for flash flooding.
Monday afternoon and evening will be active over the area. So have multiple ways to receive warnings. Make sure you have fresh batteries in your weather radio and flashlights; it could be a long night.
Putting Forecast in Perspective
To put this in perspective:
How To Get Warnings
NOAA broadcasts warnings on weather radio in a continuous loop during emergencies.
The National Weather Service lets you sign up for watches and warnings for your address.
Harris County’s Flood Warning System also lets you sign up to receive rainfall or flooding alerts for your location. The site also contains maps that show real-time rainfall, and river-channel monitoring and forecasting at gages throughout the region.
USGS has a web app called Water On the Go that shows water elevations at flood gages wherever you go in Texas.
Harris County Flood Control District’s Storm Center can connect you to a wide variety of preparedness articles and ways to summon help in an emergency.
A number of companies offer good apps for cell phones that offer warnings. I especially like one called Dark Skies that bills itself as “hyper-local” weather. It frequently tells me to the minute when a storm will arrive at my exact location…wherever I am.
You can also find links to dozens of other weather related apps and sites on my Links Page. Check them out before the storm arrives. You never know when a storm will knock out a web site, a cell tower, or power. So be prepared with multiple backups.
Posted by Bob Rehak on 3/20/2022 based on input from the NWS, HCFCD and City of Houston
1664 Days since Hurricane Harvey
Severe Weather Predicted Next Monday into Tuesday
I received an email from Jeff Lindner, Harris County’s meteorologist, around 1PM today that warned of possible severe weather from next Monday afternoon into early Tuesday Morning. As I explored it more, I also came across a fascinating academic study about the communication of weather risk that you may want to share with friends and relatives. One of the key findings: mobile home owners may need more response time than typical tornado warnings provide.
Possible Tornados, Hail, Damaging Winds, Street Flooding Early Next Week
“All severe modes will be in play Monday afternoon and evening including tornadoes, large hail, and damaging winds. The tornado threat appears highest north of HWY 105. The severe threat will be lowest near the coast and around Matagorda Bay,” said Lindner. “Heavy rainfall is also becoming an increasing concern.”
While most models show from one half to two inches of rain around Bush Intercontinental Airport, one model predicts four inches. Lindner predicts 1-2 inches of widespread rain north of I-10 with isolated totals of 3-4 inches possible. South of I-10 rainfall amounts of .50-1.0 inch will be possible.
“Given the dry grounds in place, some of this rainfall will soak in,” says Lindner. “But potential for high hourly rainfall rates poses an urban street flooding threat.” In other words, rain may fall faster than it can soak in or drain off, and then collect in streets.
NWS Cites Conditions Favorable for Supercell Formation
The National Weather Services Storm Prediction Center cites atmospheric conditions favorable to the formation of supercells, such as those that tracked across Harris County in January. Along with these supercells, they discuss the increasing potential for large hail and tornados Monday afternoon.
The Intersection of Weather and Communications
The NWS Storm Prediction Center contains a wealth of information for weather aficionados including academic publications on meteorology. Mindful of how a January tornado struck Kingwood at 1:30AM and also how the Lake Conroe release during Harvey arrived in the middle of the night, the following study caught my eye:
All researchers work in Norman, Oklahoma. They studied what time of day the public was least confident about receiving and responding to tornado warnings. Answer: between midnight and 4:00AM. Not a big surprise there. Most people are sleeping then. But the authors also studied several related questions:
Findings
The authors found the southeastern portion of the US most susceptible to nocturnal tornadoes. East Texas is on the edge of the highest risk area. They also found that:
These findings should help inform forecasters and emergency managers about communities that need more time to respond to overnight tornado events. In the meantime, change the battery in that old weather radio! It’s springtime in Texas.
Posted by Bob Rehak on 3/19/2022
1663 Days since Hurricane Harvey