Tag Archive for: severe weather

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.

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.

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

Widespread Heavy Rains Predicted Later This Week; Minor Flooding Possible

Expect heavy rains Wednesday night into Thursday – New Year’s Eve morning – as two powerful storm systems collide over Texas this week. One front will dip down from Canada, then another from California will ride up over it producing a variety of threats.

Predicted accumulations for the next 7 days. Chances of rain will increase on Wednesday and peak Wednesday night at 90%. Chances of rain will decrease on Thursday, New Year’s Eve, but peak at 70%.

The National Weather Service Storm Prediction Center predicts a marginal risk of severe storms, damaging winds and tornadoes for areas west of I-45. However, the threat from heavy rains will be more widespread. Slow-moving or training showers and thunderstorms will produce 1-2 inches for the entire region and 3-4 inches in isolated locations. One normally conservative forecaster predicts up to 5 inches. North Texas will have it worse.

Impact on Lake Houston Area

In the Houston area, the most rainfall will be east of I-45 and north of I-10 or across the region’s northeast counties.

Jeff Lindner, Harris County Meteorologist

Minor Flooding Possible

Most area streams should be able to handle the heavy rains. However, Lindner, says area watersheds could swell. He blames higher than normal run-off due to low evaporation rates and dead/dormant vegetation. The National Weather Service predicts this may result in minor flooding of low lying, poorly-drained areas.

Holiday travel may be impacted if and where accumulations occur. Take note, especially if you’ve been visiting families in north or central Texas.

How Fronts Will Interact

The strong cold front should be off the coast by Thursday morning. However the Pacific front will lift lots of moisture over the incoming cold air mass. The cooling caused by the rising air (advection) will trigger precipitation. Lindner says areas from northwest of a line between Columbus to Huntsville may see rain mixed with sleet/snow.

Space City Weather predicts potential for heavy storms on Wednesday and Wednesday night with much of the area receiving 2 to 3 inches of rainfall. “We cannot entirely rule out this precipitation turning into a wintry mix north of Houston later on Thursday,” says the popular, normally conservative service. They say they can’t rule out a few isolated areas with 5 inches. They also note that forecast certainty will improve by Tuesday, as higher-resolution models come into play.

NWS predicts cooler and drier conditions Friday through the first weekend of the new year.

Posted by Bob Rehak on 12/28/2020

1217 Days since Hurricane Harvey

Severe Weather, Heavy Rainfall Threats Return for Much of This Week

Keep your eye on the sky for more severe-weather threats this week. Harris County Flood Control Meteorologist Jeff Linder warns that the coming week could bring us 5-7 inches of rain, and higher totals in places. He says the upper level trough setting up over the southwestern US will send us one storm after another. Linder compared the current pattern to those in the springs of 2015 and 2016. We saw multiple floods across Texas in both of those years.

Rainfall total forecast for May 5 through 12.

Monday Night/Tuesday: Saturating Soils

A strong disturbance will move into southeast Texas on Monday night and Tuesday with widespread showers and thunderstorms. Heavy rainfall of 1-2 inches with higher isolated totals will be possible along with a slight severe weather threat. Lindner thinks “most of the area will be able to handle this round of rainfall as long as there is no sustained cell training that develops and the overall forward progression of the system remains fast enough to prevent rainfall totals from piling up.” What this system will likely accomplish is further saturation of the soil over the area. Lindner calls it a “primer” event for more sustained heavy rainfall toward the end of the week.

Thursday-Saturday: Flood, Severe Weather Threats

Another strong storm system will approach toward the end of the week along with a slow moving and stalling surface frontal boundary. An extremely moist air mass along with the overall slow eastward progression of the storm system moving out of Mexico are significant heavy-rainfall signals during this period. Lindner expects several inches as several rounds of slow-moving thunderstorms impact the region. Flooding and severe weather will be possible during this period. 

Rainfall Totals and Flood Risk

Rainfall totals over the next 5 days should average 4-5 inches over much of southeast Texas and there will almost certainly be higher isolated totals. The widespread nature of the incoming weather this week on top of increasingly saturated grounds, and already swollen rivers, creek, and bayous increases the flooding threat. Main concern will be the Brazos, Trinity, and San Jacinto River basins and toward the end of the week the Harris County bayous and creeks if the current forecast holds. 

Exact timing of the rainfall and storms as well as amounts and locations of the higher totals will be in flux over the next 5 days. 

Although some street flooding is possible, I suspect the main threat will be river flooding this time.

Things You Can Do to Prepare

The Tax and Memorial Day Floods in 2015 and 2016 did as much damage as many hurricanes. So it would be good to prepare an evacuation kit, just in case. Here are some tips.

Get a backup battery charger for your cell phone in case of extended power outages. Remember the 13 days Kingwood went without power after Hurricane Ike?

Change out the batteries in your flashlights and weather radio. Remember those? They still work!

Learn how to read cloud formations and what they mean. Here’s a link to a well-illustrated article about threatening cloud formations. You may also want to search for “cloud formations before tornados.”

Move your vehicle to higher ground, preferably inside a garage. Remember, large hail often occurs with severe storms and can destroy a car’s finish.

After a flash flood, stay home or stay at work.

Posted by Bob Rehak on May 5, 2019

614 Days since Hurricane Harvey