The threat of severe weather in South Texas can happen almost anytime during the year. It can range from severe thunderstorms with heavy rain, large hail, high winds, dangerous lightning, along with the possibility of tornadoes, to extreme heat and drought conditions. In addition during the winter months we can usually expect some icy conditions and the possibility of snow. While it doesn’t occur on a daily basis, we must always be prepared to deal with it whenever it does.
Here in the San Antonio area of South Texas we can and do receive a wide variety of severe weather based on several factors. The moisture from the Gulf of Mexico plays a major role. When cold fronts move into the area and mix with this moist atmosphere the results tend to produce showers and thunderstorms. Any of these storms moving in the area can become severe very quickly and this tends to occur in and around the Bexar County area. Unfortunately many frontal systems that move in from the West bring little rainfall to us here in Live Oak. Large cities tend to create heat islands and this can break up some storm fronts. In addition large cities tend to cap the atmosphere overhead and thus storms tend to miss us. As Live Oak is located on the Northeastern side of Bexar County we sometimes miss some severe weather as it tends to break up and weaken over the large city.
One important item to remember! On occasion storm systems can move into the area from the Northeast. While this is kind of rare, any large storm system moving into the area from the Northeast could bring severe weather to our City. This is especially true when it comes to tornadoes which we will discuss later on.
While severe weather occurs on a regular basis, it never really sneaks up on us thanks to the folks at the National Weather Service. The office serving the South Texas area is located at the New Braunfels Airport and it is known as the Austin/San Antonio office of the National Weather Service. The facility has state of the art NEXRAD radar and operates 24 hours a day, 365 days a year. They provide daily weather updates and issue an assortment of weather advisories, statements, and bulletins including weather watches and warnings, depending on conditions. Several other radar sites cover South Texas including one near Del Rio, Corpus Christi, and several other locations. In addition, the Storm Prediction Center in Norman, Oklahoma, monitors the weather across the nation and issues various statements regarding the possibility of severe weather.
All citizens should be familiar with the weather services statements and bulletins and fully understand what they mean. The most common are Watches and Warnings. They both pertain to a weather conditions but their meaning is very different.
Watches – A “Watch” of any kind simply means conditions are favorable for a certain type of weather to occur, over a certain area, and during a specific time frame. Generally speaking watches are issued based on atmospheric conditions when moisture is present and storms fronts are expected.
Warnings – A “Warning” on the other hand means that the condition is happening now. A Severe Thunderstorm Warning posted for Bexar County until a certain time means that a severe storm, based on high winds, hail, and rainfall is showing up on radar and is moving into the area. The most dangerous would be a tornado warning. These are issued when either an actual funnel cloud has been reported on the ground by a certified weather spotter or when radar indicates the possibility of a rotating storm cell which could indicate a tornado. Sometimes this indication is known as a “Hook Echo” on the radar. The hook so to speak is the actual funnel cloud however radar cannot tell if the funnel cloud is actually on the ground.
Severe weather can be dangerous and deadly too. One of the biggest problems around the area is flash flooding and there are many low water crossings that are located in San Antonio and Bexar County. Every year about 150 lives are lost due to flash flooding and the majority of these deaths occur at low water crossings. People continue to drive through low water crossings and are swept away by the rushing water.
Tornadoes also claim many lives each year as well. The San Antonio area is south of the famed “Tornado Alley” however every year we usually have at least one or two funnel clouds sighted in this area. As a reminder any thunderstorm can spawn a tornado with little or no warning. Generally speaking straight-line winds actually do more damage than tornadoes, and they also can occur during most thunderstorms.
Severe thunderstorms can occur anytime of the day or night however they occur most often in the late afternoon and into the early evening hours. Daytime heating combined with a lot of moist air from the Gulf and a frontal passage can trigger these storms on a regular basis, especially during the springtime from March – May. As such, the National Weather Service and the State of Texas promotes this as severe weather season and a proclamation is issued at the end of February by the Governor and our Mayor.
Lightning Safety Fact Sheet
Severe Weather Awareness Fact Sheet
CoCoRaHS, the Community, Collaboration, Rain, Hail, and Snow network:
The National Weather Service (NWS) continues to look for additional folks to become members of their CoCoRaHS network.
This program was started back in the late 1990s by the National Weather Service in Colorado and it continues to grow. The network now has volunteers in all 50 states and hopes to have 20,000 members by the end of the year. Their goal is to have weather observers across the nation who report rain, hail, and snow amounts on a daily basis along with other data using the internet or by telephone.
At the present time there are 94 active stations in San Antonio/Bexar County, and we have 2 in the City of Live Oak.
You can join the network by simply going to their web site and signing up or to get additional information regarding the program. Signing up is free, however in order to establish a monitoring site in your backyard, you must purchase a special rain gauge, similar to the type actually used by the weather service. This is necessary to insure the accuracy of the program as not all store bought gauges are the same. The cost is nominal and it can ordered on line or by telephone.
For additional information you can visit the Austin/San Antonio office of the National Weather Service at https://www.weather.gov/ewx/ or you can go directly to the CoCoRaHS web site at www.cocorahs.org On the web site for the Austin/San Antonio office scroll down to the bottom of the opening page and you will see the icon at the bottom of the page on the right hand side.
You can also contact the Live Oak Office of Emergency Management at 653-9140, Extension 2379 for additional information on this program.
Hurricane season begins on June 1st and runs through November 30th each year. At the present time, the State of Texas ranks 2nd in the nation for hurricanes that have some impact on the state. Florida ranks number 1 in case you are wondering who has top honors in that category. That time frame isn’t always the case as some storms have formed in May and sometimes hurricanes continue to form in December.
While a hurricane making landfall along the Texas coastline is not going to have a direct impact on the San Antonio area, things could actually get pretty intense here under the right circumstances. Being approximately 150 miles from the coast the storm surge is not going to affect us, however depending on the size of the storm (Category 1, 2, 3, 4, or 5) and the point where it makes landfall, along with the storms forward speed we could experience some severe weather conditions in Bexar County. The worst part of a hurricane making landfall is the so called Northeast Quadrant. This is where the most intense wind is located and where the best chance is for the formation of tornadoes. As a reminder, once a hurricane makes landfall it can spawn many tornadoes as it moves inland.
In 1988 Hurricane Gilbert made landfall along the Texas Coast and moved inland. It came in between Corpus Christi and Brownsville and we were on the Northeast side of the storm. We had very heavy rains in San Antonio and several tornadoes touched down in Bexar County and within San Antonio. One hit the former Kelly AFB causing heavy damage and another hit the medical center area and heavily damaged an apartment complex and the Texas Medical Center itself.
In the event a major hurricane (Category 3 or higher) makes landfall along the coast of Texas near Corpus Christi and it comes in with enough forward speed, the affects could reach all the way to Bexar County and the City of Live Oak. In addition to heavy rainfall, we could experience sustained winds reaching hurricane speed – 74 MPH, with gusts reaching 100 MPH. While this would be a very rare occurrence it could happen and this could cause a lot of damage to homes and businesses, specifically roof damage.