...2018 Spring Flood Outlook for Southeast Texas and Southwest
and Central Louisiana...
...Above Average Flood Potential on the Sabine and Neches Rivers
in Southeast Texas and on the Red, Calcasieu, Mermentau and
Vermilion Rivers in Central and Southwest Louisiana...
This outlook considers antecedent rainfall, snowpack, soil
moisture, streamflow and water supply conditions compared to
climatology, combined with longer-term 90-day climate outlook
forecasts for temperatures and precipitation across the forecast
area.
The primary factor in the development of significant river
flooding over most of the region is the occurrence of excessive
rainfall in relatively short periods of time, even for areas
where drought conditions persist or have developed.
...Outlook for southeast Texas including the Neches and Sabine
river basins...
Potential for spring flooding in this area is ABOVE AVERAGE
at this time.
Above normal rainfall has fallen across portions of the Neches and
Sabine River Basins during the past few weeks. Similar to last
year, recent rain events have lead to increased soil moisture
content across southeast Texas. Streamflow conditions on the
Neches and Sabine River are above normal. Area reservoirs are near
conservation levels. Percent of conservation storage capacity is
given below:
3/1
B.A. Steinhagen Lake 91%
Sam Rayburn Reservoir 100%
Toledo Bend Reservoir 100%
...Outlook for the Atchafalaya River...
Until the past couple of weeks, the flood season was uneventful
on the Ohio and Mississippi Rivers, but recent heavy rainfall has
led to significant increases in streamflows. This is expected to
impact the Atchafalaya River over the next few weeks as this
water makes its way downstream. Streamflows are well above normal
and the river is expected to rise through mid to late March, with
minor to moderate flooding expected on portions of the
Atchafalaya River.
The percent of normal streamflow is given below:
2/28
Atchafalaya River Simmesport LA 205%
Based on existing soil moisture, streamflow conditions, and normal
spring rainfall patterns, an ABOVE AVERAGE flood potential is
expected along the lower Mississippi and the Atchafalaya Rivers.
The magnitude of future crests will depend on the frequency,
intensity, and extent of spring rains, along with the amount and
extent of any upstream accumulation of snow and resultant
snowmelt.
...Outlook for the Lower Red Basin...
Streamflows and soil moisture are well above seasonal averages.
Minor to moderate flooding is occurring on portions of the Red
River, with minor flooding occurring and expected to continue on
the Red River at Alexandria.
Percent of available reservoir flood control storage for upstream
reservoirs is given below:
2/28
Cooper Res. TX 0%
Texarkana Res. TX 75%
Lake O` Pines TX 75%
Based on existing soil moisture, streamflows, and normal spring
rainfall patterns; an ABOVE AVERAGE flood potential is expected
over the lower Red River Valley.
...Outlook for the Calcasieu/Mermentau and Vermilion Basins in
southwest Louisiana...
Soil moisture content is well above normal across the area.
Streamflows are running well above normal on the Calcasieu River,
with slightly above normal streamflows on the Mermentau River and
near normal streamflows on the Vermilion River. Moderate to major
flooding is occurring or expected at several locations on the
Calcasieu River. Flooding on the Mermentau and Vermilion Basins
will be dependent on the intensity and extent of spring rains.
Observed daily streamflows as a percent of median are given below.
2/28 3/2
Calcasieu River Glenmora LA 2255% 1341%
Calcasieu River Kinder LA 1103% 990%
Based on existing soil moisture, streamflows, and normal spring
rainfall patterns; an ABOVE AVERAGE flood potential is expected
over the Mermentau, Calcasieu and Vermilion Basins.
...Extended Temperature and Precipitation Outlook...
The 8-14 Day Outlook issued by the NWS Climate Prediction Center
indicates chances of near normal temperatures and precipitation
across central and southwest Louisiana and southeast Texas.
The 30 Day Outlook indicates chances of above normal temperatures
and precipitation. Meanwhile, the 90 Day Outlook indicates
chances of above normal temperatures, with chances of below normal
precipitation.
The U.S. Drought Outlook indicates no drought development is
expected. Elevated soil moisture in basins across the area may
result in substantial runoff from any heavy spring rains.
Typically, river flooding is increasingly probable during the
spring months in this region, where convective storms can quickly
produce rapid runoff causing flash-flood and mainstem flood
conditions. Slow vegetation growth combined with the possibility
of near normal precipitation could enhance the potential for
spring flooding across in this region.