NWS Archives - Reduce Flooding

NWS Says La Niña Has Ended, Likely Impact on Weather

On March 9, 2023, the Climate Prediction Center of the National Weather Service (NWS) announced that La Niña conditions which persisted for 3-years have finally ended. But we are not shifting directly into El Niño. Instead, we’re entering a transitional phase. NWS expects neutral conditions to continue through the Northern Hemisphere into spring and early summer of 2023.

La Niña and El Niño represent opposite phases of what meteorologists call ENSO, the El Niño Southern Oscillation in the Pacific Ocean. They govern recurring climate patterns across the tropical Pacific and have a cascade of global side effects, says NWS.

The patterns shift back and forth irregularly every two to seven years. This past La Niña phase lasted three years, an unusually long time.

NWS predicts that ENSO-neutral conditions will continue through the spring. The weather service also predicts El Niño conditions to form during summer 2023 and persist through the fall.

Impacts on Weather

The oscillation brings predictable shifts in ocean surface and atmospheric temperatures. These shifts disrupt the wind and rainfall patterns across the tropics.

El Niño brings cooler, wetter conditions to the southern U.S. in winter months. It also brings stronger steering currents that can disrupt low-pressure systems coming off the coast of Africa that turn into hurricanes.

La Niña, on the other hand, usually means less disruption, more Atlantic storms, and deeper droughts in the southern U.S. But we’re finally putting the most recent La Niña behind us.

ENSO Influence on Atlantic and Pacific Hurricane Seasons

The continental United States and Caribbean Islands have a substantially decreased chance of experiencing a hurricane during El Niño and an increased chance of experiencing a hurricane during La Niña. These maps (by NOAA Climate.gov, based on originals by Gerry Bell) explain why.

*Typical **El Niño** effects on Pacific and Atlantic seasonal hurricane activity.*

Overall, El Niño contributes to more eastern and central Pacific hurricanes and fewer Atlantic hurricanes. Conversely, La Niña contributes to fewer eastern and central Pacific hurricanes and more Atlantic hurricanes – exactly the opposite.

*Typical **La Niña** effects on Pacific and Atlantic seasonal hurricane activity.*

Other Influences on Hurricane Formation: AMO

NOAA also says that other oscillations, such as the Atlantic Multi-Decadal Oscillation (AMO) also influence hurricane formation. The warm phase of the AMO is associated with warmer sea surface temperatures and high hurricane activity in the main development region of the Atlantic between Western Africa and the Caribbean.

“The hurricane activity in any given season often reflects a combination of the multi-decadal signals and ENSO,” says NOAA.

For More Information

For a fuller discussion of how El Niño and La Niña influence other aspects of weather worldwide, check out NOAA’s Climate.gov, especially the FAQ page.

Also, the Associated Press ran an interesting story this morning by Seth Borenstein. The headline: “La Nina, which worsens hurricanes and drought, is gone.”

Borenstein says NOAA gives El Niño a 60% chance of returning this fall. But there’s also a 5% chance that La Niña will return for an unprecedented fourth winter.

We should have more certainty in a few months.

Posted by Bob Rehak on 3/9/23

2018 Days since Hurricane Harvey

Strong Thunderstorms, Street Flooding, Tornados Possible Tomorrow

Update: 10/28/22 11am: Today’s reports indicate the highest severe storm risk is shifting SW of Houston and offshore. Experts now predict 1-2 inches of rain for the Houston area today. Areas offshore are already getting 2-4 inches per hour.

Tomorrow will likely bring strong thunderstorms. Rainfall rates could exceed the capacity of street drains leading to localized street flooding. And the severe weather may also spin up some tornados, according to Harris County’s meteorologist and the National Weather Service (NWS).

Heavy Rainfall

NWS predicts two to three inches of rain could fall on Friday, as warm, moist air pushing in from the Gulf collides with a cold front pushing in from the northwest. Jeff Lindner, Harris County meteorologist, predicts the worst period for us will be Friday afternoon.

Tornados Possible

The NWS Storm Prediction Center in Norman, Oklahoma, issued this warning for Friday . It shows a marginal risk of severe weather for the entire Houston area and a slightly higher risk for areas south and west of us.

Reasons for Concern

For the weather wonks reading this, Lindner cites an unusual convergence of storm systems at different levels of the atmosphere.

A trough will begin to move eastward toward Texas later today. Surface pressures will begin to fall this afternoon as low pressure develops ahead of the approaching mid-level low. Southeast winds will increase today, letting Gulf moisture quickly return to coastal Texas.

As the mid-level low approaches us, it will meet the northward-moving, moisture-laden warm front moving in from the Gulf.

Severe threats will be highest along the boundary. Tropical moisture will march quickly northward tonight on a 30-knot low level jet. Precipitable waters – the amount of moisture in a column of air – will equal 1.8 inches by Friday morning over much of the region.

As large-scale lift increases over the developing warm sector, showers and thunderstorms will develop from southwest to northeast across the region.

The cold front associated with the mid-level low will sweep west to east across southeast Texas on Friday afternoon, touching off more thunderstorms. The front will slow Friday night, so showers will linger over the area.

Severe Threat:

The surface low approaching from the northwest will meet the warm front coming from the opposite direction along a NW to SE axis on Friday. This warm front will extend from near San Antonio to near Freeport during the day and produce strong to severe thunderstorms. Low-level winds near the warm front will circle back toward the ESE and enhance low-level storm rotation.

Such collisions are notorious for tornado production, according to Lindner. Discrete cells may develop ahead of the line of storms approaching from the west. The location of the greatest severe risk will depend on where the warm front sets up Friday morning. Areas along and south of the front will have the highest risk.

If the warm front moves just a few miles farther north, it will increase risk to the Houston metro area. Kingwood was struck by tornados in a similar setup earlier this year.

Damaging winds will be the main threat. The worst of the storms should be over by 3-5 pm Friday, but lighter rains may linger well into the evening hours.

Heavy Rainfall:

Moisture will deepen Thursday into Friday. By Friday morning, a saturated air mass will be in place over the region. “Strong divergent lift coupled with low-level inflow will increase the potential for heavy rainfall along with cell training from southwest to northeast.”

Lindner describes himself as “aways wary of such setups.” They can help anchor and train convection.

The overall pattern favors supercell formation with both a tornado and heavy rainfall risk.
Jeff Lindner, Harris County Meteorologist

These storms could become significant rainfall producers – if they become sustained along the warm frontal boundary. The good news is that the ground is dry and can handle several inches of rainfall. “However, rainfall rates may exceed localized drainage capacities and result in some street flooding regardless of the dry ground conditions,” says Lindner.

Weekend:

Cloudiness should linger much of Saturday keeping temperatures in the 50’s under northerly winds. South of the cloud line temperatures will warm into the 70’s. Where that line will be Saturday is hard to determine. Clouds should erode Saturday night with mostly clear skies. Sunday will be mild.

Tropics:

The hurricane season has another month to go. It isn’t over yet! The National Hurricane Center now gives an area of low pressure moving WNW across the Caribbean a 50% chance of turning into a tropical depression in the next five days. No one is yet predicting what will happen if it does.

Posted by Bob Rehak on 10/27/22 based on information from Jeff Lindner, NWS, and NHC

1885 Days since Hurricane Harvey

NHC Gives 40% Chance of Formation to 91L Within 5 Days

Another tropical wave is moving into the Caribbean along the same track as Ian. As of Monday morning at 8 a.m., the National Hurricane Center gives it a 40% chance of developing within 5 days. Currently, the tropical wave is several hundred miles east of the Windward Islands and moving westward at 15-20mph. The NHC has designated this area of investigation as 91L.

*Atlantic tropical waves and directions.* *Invest 91L is orange.*

While Invest 91L looks fairly impressive on satellite images (see below), Jeff Lindner, Harris County meteorologist says, “There does not appear to be any closed low-level circulation yet. This wave should reach the eastern Caribbean Sea around mid-week and the western Caribbean by this weekend.”

*91L is the storm north of the Guyanas and Suriname on the north coast of South America.*

Says Lindner, “Conditions generally become favorable for development along the track of 91L, but when compared to Ian, model solutions are much more varied with development potential and also much more scattered. Some models take the storm into Central America, others predict it will track toward Puerto Rico and the Dominican Republic.

For now, watch and wait.

Orlene Moves Inland Over Mexico

In the meantime, the eastern Pacific is fairly active. NHC is tracking three storms. Two are moving northwest parallel to the Mexican coast as a third – Hurricane Orlene moves inland near Mazatlán.

Mid- and high-level moisture from Orlene will stream across our area later in the week. However, our air is so dry right now that precipitation aloft will likely not reach the ground.

Glancing Blow from Frontal Boundary Later in Week

Lindner also predicts, “Toward the end of this week, moisture may return to Texas from the Gulf of Mexico ahead of a front that will drop into the eastern U.S. The front should only strike a glancing blow to Texas. Most of it will head more southeast toward the Tennessee Valley. So rainfall potential for Houston will remain low. Our dry pattern will likely continue.”

The National Weather Service Storm Prediction Center sees little to no severe threat.

Posted by Bob Rehak on 10/3/2022 at 11:30 am

1861 Days since Hurricane Harvey

Slight Chance of Tropical Formation In Gulf This Weekend

The National Hurricane Center (NHC) issued a tropical weather outlook today that shows a 10% chance of tropical formation in the Gulf. This is your “heads up.” Hurricane season is ramping up.

NHC will provide an update on chances for development later this evening, but models show growing support that a tropical depression or weak tropical storm is possible along the middle or lower TX coast by Sunday. The system will then moving inland over south Texas late Sunday into Monday, according to Jeff Lindner, Harris County’s meteorologist.

Latest Satellite Imagery

Here’s what the Gulf looks like on satellite Friday evening. The system will track W to WSW over 85-90 degree waters toward the mid- or lower-Texas coast on Sunday.

Currently, disorganized showers and thunderstorms over the north-central Gulf of Mexico are associated with an area of low pressure centered just offshore of the southern coast of Louisiana. There’s no tropical formation yet. But that could change.

As of 2PM EDT today, NHC listed the formation chance through:

48 hours…low…10 percent.
5 days…low…10 percent.

Rainfall Potential

Regardless of development, locally heavy rains are possible along portions of the Texas coast through the weekend. For more information about the potential for heavy rainfall, please see the National Weather Service site and the Weather Prediction Center.

Highest rain chances in next few days for SE Texas are around mid-day Saturday.

Decent rain chances exist for the next three days, especially along the coastline south of I-10.

Jeff Lindner, Harris County’s meteorologist says, he expects most of the shower and thunderstorm development associated with this low pressure system to happen near the coast and offshore. He expects lesser chances inland to the north as high pressure and drier air begins to build southward from the northeast.

Forecasters use a measurement called PWS (Precipitable Waters) to predict amounts of rainfall. PWS measures the amount of water vapor in a column of air. This weekend with PWS of 2.2-2.3 inches and possible cell training, Lindner warns that a quick 2-3 inches of rainfall in less than an hour will be possible. Even though grounds are dry and should be able to handle the rainfall, some street flooding will be possible with those rates.

No River Flooding Expected

However, National Weather Service expects no significant river flooding in the next five days.

Tide Report

According to Lindner, tides are already elevated along the coast due to the full moon. Easterly and southeasterly low-level winds on the north side of the low may bump seas up a bit over the weekend and push tides a little higher. He expects water to be way up on the beaches at high tides over the weekend.

Monitor forecasts closely over the weekend for any changes.

Posted by Bob Rehak on 8/12/2022

1809 Days since Hurricane Harvey

Hurricane Records

Today, I discovered a fascinating 49-page document produced by the National Weather Service, the National Hurricane Center, NOAA and the National Climatic Data Center. It contains hurricane records going back to 1851. It covers the deadliest, costliest and most intense U.S. tropical cyclones and other frequently requested facts. Unfortunately, it only goes through 2010. But the wealth of information on the period it covers more than makes up for that.

Like the Baseball Encyclopedia for Weather Geeks

It’s like the Baseball Encyclopedia for tropical storms…a must read for weather geeks and anyone who wants to impress out-of-town friends. Texas plays a prominent role in this chronicle.

From Page 8. Mainland United States tropical cyclones causing 25 or more deaths, 1851-2010. The black numbers are the ranks of a given storm on Table 2 (e.g. 1 is the deadliest all-time – the Galveston Hurricane of 1900). The colors are the intensity of the tropical cyclone at its maximum impact on the United States.

A look at the lists reveals striking facts. For instance:

Fourteen out of the fifteen deadliest hurricanes ranked Category 3 or higher intensity
Large death tolls resulted largely from storm surge 10 feet or higher
A large portion of the damage in some of the costliest storms resulted from inland floods caused by torrential rains
One third of the 30 deadliest hurricanes ranked category 4 or higher
Only seven of the 30 deadliest hurricanes occurred between 1985 and 2010 while more than two thirds of the costliest hurricanes occurred during the same period.

A Look Behind the Facts

All costs are adjusted for inflation, so that’s not the major issue. Migration is. 1990 Census data showed that 85% of U.S. coastal residents from Texas to Maine had never experienced a direct hit by a major hurricane. But we have more risk now because more than 50 million people have moved to coastal areas since then.

The study warns, “If warnings are heeded and preparedness plans developed, the death toll can be minimized. However, large property losses are inevitable in the absence of a significant change of attitude, policy, or laws governing building practices (codes and location) near the ocean.”

Filled with Tables, Maps and Insight

One of the most interesting features: maps that show the tracks of record setting storms during the entire period and during each decade.

Amaze your friends with trivia, such as:

Average number of tropical cyclones per year AND how it has varied in different periods.
Years with the most and least hurricanes and landfalls.
Earliest and latest hurricane formations (hint: March 7 and December 31).
Longest- and shortest-lived hurricanes.
Lowest pressure in the Atlantic basin.
Most hurricanes occurring in Atlantic basin at one time.
Number of hurricanes in each month.
Hurricane strikes of various categories by state.
When hurricanes are most likely to strike different areas.
Average return periods for hurricanes in different areas.
Hurricane landfall CYCLES.

That last one really caught my eye.

Hurricanes tend to cluster in certain areas during certain decades!

Biggest Lesson Learned

The study concludes with another warning. “The largest loss of life can occur in the storm surge, so coastal residents should prepare to move away from the water until the hurricane has passed! Unless this message is clearly understood by coastal residents through a thorough and continuing preparedness effort, a future disastrous loss of life is inevitable.”

To read the full study, click here.

This is a genuine work of scholarship dished up in a way that makes it accessible to the general public. That takes some talent! Credits go to Eric Blake and Christopher Landsea of the NHC, and Ethan Gibney of the National Climatic Data Center.

Posted by Bob Rehak on 7/8/22 based on a study by NOAA, NWS and NCDC

1774 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.

*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

Texas Hurricane History

I came across a fascinating, though slightly dated study by David Roth of the National Weather Service called “Texas Hurricane History”. The 80-page document is filled with trivia that will let you astound friends and family.

Texas Hurricane History From 1527 to 2008

It starts with a section on climatology, then has a list of Texas hurricanes dating back to 1527. The list goes up through Ike in 2008.

Next, there’s a section on hurricane records. It shows dates, wind speeds, deaths, minimum central pressures, origins, tracks and more. Finally, there are numerous chapters devoted to hurricanes by century that contain historical narratives on each major storm.

The Last Indianola Hurricane: A Prequel to the Great Galveston Hurricane

Most people in Houston have heard the story of the Galveston hurricane of 1900. And there’s a lengthy discussion of it in Roth’s history. The storm changed the course of this region’s economic development.

But I had never before heard of the “Last Indianola Hurricane.” Long before Galveston, a Category 4 storm changed the history and economic development of another part of Texas by wiping out another of Texas’ major ports.

The city of Indianola was founded on the west shore of Matagorda Bay in 1844 by immigrants from Germany, Switzerland, and France. It quickly grew to handle the business west of there, but fell prey to frequent hurricanes including one in 1875 that killed 176 people.

*Image from Calhoun County Museum: Debris from the 1875 hurricane that hit Indianola, Texas. The town rebuilt after the storm only to destroyed 11 years later.*

On August 18-20th, 1886, Indianola suffered a fatal calamity in another hurricane. Says Roth, “Winds increased throughout the night of the 19th. Matagorda Bay began to invade the city by daylight on the 20th. The wind increased to 72 mph before the Signal Office building collapsed; the observer was killed by a falling timber during his attempt at escape. A lamp in the office burned down the building, along with more than a block of neighboring buildings on both sides of the street, despite the heavy rain. Although the storm was of shorter duration than the one in 1875, winds were considered higher. A storm surge of 15 feet inundated the region, covering the base of the Matagorda Island lighthouse with four feet of water. A large schooner was carried five miles inland.”

“The town was a universal wreck; not a house that was left standing was safe to dwell in,” says Roth. “Most people in town left for the greener pastures of Victoria and San Antonio.”

In this part of Texas, that’s a lesser known prequel to the Galveston hurricane of 1900 that killed more than 8,000 people. But the effect was the same. It led to the rapid growth of safer cities farther inland.

Amazing Facts from Texas Hurricane History

For those who think only recent hurricane have high winds, Roth points to Hurricane Celia that hit Aransas pass in 1970 with 180 mph winds.

And before Harvey, four storms dumped 40″ or more of rain on Texas (in 1921, 1978, 1979, 2001).

Roth’s Texas Hurricane History is a work of scholarship. It contains an eight-page bibliography containing hundreds of references to books and newspaper articles, some of which date back more than 125 years – long before the digital age made such research easy.

For future reference, I will also link Roth’s history to the Reports Page under the Major Storms tab.

As Roth says in his preface, “More hurricanes will strike Texas over the coming years. Learning what happened in past storms can help to prepare you for the future. If the past is ignored, mistakes made in previous storms are likely to occur again.”

Posted by Bob Rehak on 9/4/2021

1467 Days since Hurricane Harvey

Houston in Bullseye: NWS Predicting Another 4-6 Inches of Rain in Next 5 Days

The National Weather Service released this map around 7 a.m. Houston time this morning. It shows Houston in the bullseye with another 4 to 6 inches of rain predicted in the next five days. Jeff Lindner, Harris County Meteorologist, warns that flash flood watches may be needed by Friday into the weekend.

*Houston Area is in the Bullseye and could receive another 4-6 inches of rain in the next five days.*

Atmosphere Moisture Levels Support 1-3 Inches Per Hour Later Today

Yesterday’s active weather pushed down toward the coast overnight. The local air mass stabilized by Thursday morning. But afternoon heating and a rapid influx of Gulf moisture favor the development of numerous thunderstorms later today over the region.

Moisture levels in the atmosphere support heavy rainfall with hourly rainfall rates of 1-3 inches per hour possible under the strongest cells. Lindner notes that we saw this yesterday evening throughout the Lake Houston area.

Heaviest Rains Expected Friday

However, the main storm system will begin to move slowly into southwest and west TX on Friday. It will dominate local weather through the weekend, according to Lindner, as several disturbances rotate around around it and feed off the near-continuous stream of rich Gulf moisture over the area.

Expect widespread showers and thunderstorms Friday through the weekend with frequent rounds of heavy rainfall.
Jeff Lindner, Harris County meteorologist

Upper level winds will support cell training over the area this weekend. Flash flooding will be a concern.

Rainfall Amounts, Impacts

Additional rainfall amounts of 4-6 inches will be possible over the next 5 days. Much of this will fall during periods of heavy rainfall. Isolated totals could be significantly higher under any areas of sustained training. Hourly rainfall rates of 1-3 inches will be possible, which could support rapid street flooding.

Ground Still Saturated

Grounds are still saturated from heavy rainfall in May. And some watersheds are still elevated from the rainfall yesterday evening. Rainfall over the next several days will likely generate run-off into local watersheds resulting in rises. Any areas of sustained heavy rainfall will increase the threat for channel flooding given the delicate groundwater situation currently in the area.

Posted by Bob Rehak on June 3, 2021, based on info from the NWS and HCFCD

1074 Days since Hurricane Harvey

Flash Flood Watch, Flood Warning Extended

Flood Watch through 7 P.M. For Most of Region

The National Weather Service (NWS) has issued a flash flood watch for most of the Houston region. The watch will last through 7 P.M. this evening.

Flood Warning Through Saturday Morning For Smaller Areas

In addition, NWS has issued a flood warning for counties to the west and east of Houston. See map below.

NWS predicts minor flooding for East Fork San Jacinto near New Caney affecting Harris, Liberty and Montgomery Counties.

Precautions:

Persons with interests along these streams should keep alert to rising water and take all precautions to protect their property. Do not drive or walk into flooded areas the depth and water velocity could be too great for you to cross safely. Avoid any water covered roads and find an alternate route. Livestock and equipment should be removed from the flood plain immediately. Stay tuned to NOAA Weather radio or other news sources for further updates. Turn around, don`t drown when encountering flooded roads. Most flood deaths occur in vehicles. Additional information is available at www.weather.gov.

Today’s Forecast: More Heavy Rain Probable

According to Harris County Meteorologist Jeff Lindner, “…deep tropical moisture to the west will help create a series of upper level disturbances once again today. The result: scattered showers and thunderstorms that should begin with daytime heating. As a disturbance approaches the area this afternoon from the west, showers and thunderstorms will likely become slightly more organized.”

The air mass over the Lake Houston Area remains capable of heavy to excessive short term rainfall rates. Yesterday, 5-7 inches of rain fell over northeast Harris County in 4-5 hours. 8-12 inches fell over Austin County near Bellville.

Hourly rainfall rates of 2-3 inches per hour were common on Monday and the same air mass is in place today.

Rainfall today will likely average between 1-2 inches over the region, but isolated totals of 5-6 inches will be possible. Short range models indicate areas along and northwest of US 59 could be the prime location today for heavy rainfall. However, much of this will depend on:

Where storms develop
If and where any training develops
If any storms anchor in place.

Grounds are saturated from the recent rainfall. During the last 7 days, that rainfall has averaged 5-7 inches over much of the region with isolated totals of 10-14 inches.

Watersheds are already elevated this morning due to the recent rainfall and ongoing run-off over the area. Additional heavy rainfall will quickly run-off creating new rises.

*Bens Branch at Kingwood Drive around 6PM on 5/24/21 after a 4-inch rain. Additional rains today, if heavy, could force creeks like this even higher.*

Rapid onset flash flooding of streets and poor drainage areas will be the primary concern today, but should heavy rainfall impact already elevated and swollen watersheds some flooding would be possible.

We should get a break from the rain Thursday and Friday, but more rainfall could enter the picture by this weekend, driving up rain chances yet again.

It’s been a wet month and will get wetter.

River and Lake Report

From Harris County Flood Warning System at 6:20 AM, 5.25.21.

In the upper right at the highest red icon, Peach Creek at FM2090 is three feet out of its banks. This area has flooded three times this month.

The yellow icon below it and to the right is the East Fork at FM2090. It is still two feet within its banks, but additional rainfall today could cause flooding.

The red icon at the northeastern tip of Harris County is the East Fork at FM1485. It is out of its banks again for the third time this month.

Lake Conroe is up about a half foot and releasing almost 1600 Cubic Feet Per Second.

According to the Coastal Water Authority, Lake Houston is almost a foot and a half above normal and still releasing.

*From Coastal Water Authority at 5:30 am on 5/25/2021*

Posted by Bob Rehak at 6 a.m. 5.25.21 based on information from NWS and HCFCD

1365 Days since Hurricane Harvey

More Than Half the Rain This Year Has Fallen in May

According to the rain gage in my back yard, more than half the rain this year has fallen this month. I recorded:

Year to date = 24.98 inches
Month to date = 12.72 inches

That’s 51%.

If that’s not impressive enough for you, consider this.

11.19 of the 12.72 inches in May fell this week.
Bob’s backyard rain gage

The week isn’t even over for another 15 hours, and it’s still raining.

*Street flooding on West Lake Houston Parkway near Kingwood Drive on 5/17/21 after 5.5 inches of rain fell in about 2.5 hours.*

This May Compared to 30-Year Average for May

Compare this to the 30-year running average at Bush Intercontinental Airport – 5.09 inches. We’ve already gotten more than twice the average for the month, this week.

May is usually the third wettest month of the year after June (5.93 inches) and October (5.70 inches).

The record for May is 14.39 inches in 1970. That means we’re 1.39 inches short of the record. The NWS predicts another inch may fall today in the Lake Houston Area. And we have another 8 days left in the month with a substantial chance of rain every day through next Wednesday. So this could easily become the new record…at least according to Bob’s backyard gage. (The official one is at the big airport, of course.)

Below are the official stats. They also include norms and extremes for temperature, wind, cloudiness and more.

Posted by Bob Rehak on 5/22/2021 based on information from the National Weather Service

1362 Days since Hurricane Harvey

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