Here is where the lakes and the forecast stand on Sunday evening, September 27. There are no flood watches, flood warnings or flash flood warnings in effect for Harris, Montgomery or Liberty counties. One air quality alert is active: the Texas Commission on Environmental Quality has declared an Ozone Action Day for the Houston, Galveston and Brazoria area for Monday, September 28.
Lake levels at a glance
| Lake | Level | Percent full | Reading |
|---|---|---|---|
| Lake Houston | 42.18 feet | 98.7 percent | 5:30 p.m. Central, Sunday, September 27 |
| Lake Conroe | 199.60 feet | 93.5 percent | Daily value, Sunday, September 27 |
The level figures come from two different kinds of reading. Lake Houston’s elevation is an intraday gauge reading taken every 15 minutes. Both percent full figures, and the Lake Conroe elevation, are once daily values published by the state.
Lake Houston
The USGS gauge at Lk Houston nr Sheldon, TX, site number 08072000, read 42.18 feet at 5:30 p.m. Central on Sunday, September 27.
Across the past 48 hours the gauge moved between 42.18 feet and 42.29 feet, a spread of just over one tenth of a foot across 190 readings. Both ends of that range were set on Sunday. The high came at 11:45 a.m. and the low at 3:15 p.m., and the lake has held at or just above that low through the evening reading. The 42.18 foot figure is the lowest reading in the 48 hour window, and it is nine hundredths of a foot below the 42.25 feet reported in Sunday morning’s post.
The Texas Water Development Board’s daily value for Lake Houston is 42.23 feet and 98.7 percent full for the same date. That is five hundredths of a foot above the evening gauge reading, which is the normal gap between a once daily figure and an intraday one taken later in the day rather than a disagreement between the two agencies.
The lake sits within its normal operating band. Nothing in Sunday’s data indicates a flood condition.
Lake Conroe
The Texas Water Development Board put Lake Conroe at 199.60 feet and 93.5 percent full in its daily value for Sunday, September 27. That is two hundredths of a foot below Saturday’s 199.62 feet, with percent full unchanged. The reservoir has declined a little each day for more than a week.
Lake Conroe belongs in a Lake Houston forecast because San Jacinto River Authority releases from Lake Conroe flow down the West Fork of the San Jacinto River into Lake Houston. What happens upstream in Montgomery County is part of the flooding picture in Kingwood, Humble and Atascocita, which is why this page carries both lakes rather than one.
The forecast
Tonight: Partly cloudy, with a low around 74 degrees. Southeast wind 0 to 5 mph. Chance of precipitation 5 percent. No heat index value was published for this period.
Monday: Mostly sunny. High near 94 degrees, with temperatures falling to around 90 in the afternoon. East wind 0 to 10 mph. Chance of precipitation 10 percent. No heat index value was published for this period.
Monday night: Mostly clear, with a low around 73 degrees. Southeast wind 0 to 10 mph. Chance of precipitation 0 percent.
Active alerts
No flood watches, flood warnings or flash flood warnings are active for Harris, Montgomery or Liberty counties.
One alert matched those three counties. The National Weather Service Houston/Galveston office issued an Air Quality Alert at 5:31 p.m. Central on Sunday, September 27, carrying a Texas Commission on Environmental Quality Ozone Action Day for the Houston, Galveston and Brazoria area for Monday, September 28. It covers inland and coastal Harris County and runs through 8 p.m. Monday. TCEQ says atmospheric conditions are expected to favor high ozone levels, and suggests sharing a ride, conserving energy and avoiding drive through lanes. Nothing is active for Montgomery or Liberty counties.
This replaces the Ozone Action Day that covered Sunday, which expires at 8 p.m. Sunday evening.
Sources
Lake Houston elevation from the U.S. Geological Survey gauge at Lake Houston near Sheldon. Percent full for both lakes, and the Lake Conroe elevation, from the Texas Water Development Board reservoir pages for Lake Conroe and Lake Houston. Forecast and alerts from the National Weather Service Houston/Galveston office. Gauge readings are provisional and subject to revision by the USGS. Texas Water Development Board daily values are also sometimes restated after publication.
