Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 271711
1211 PM CDT WED MAY 27 2015

                     VALID MAY 27 THROUGH JUNE 1


                  ...METEOROLOGICAL DISCUSSION...
An upper level disturbance moved over North Texas yesterday causing
some additional heavy rainfall and severe weather to impact portions
of North and Southeast Texas. Total rainfall amounts of 3-4 inches
were reported across Southeast Texas during the early morning hours.
As a result, this heavy rainfall caused some additional rises across
the San Jacinto and Brazos River systems. Currently, the activity
associated with the upper level disturbance is moving off towards
the east. The heaviest precipitation has moved offshore and is not
significantly impacting any of the coastal basins at this time.

For the remainder of the day, scattered showers and thunderstorms
are expected for a good portion of the WGRFC area, due to the very
unstable environment in place. However the main area for any
organized activity is expected across North and Central Texas
during the late afternoon and evening hours. Rainfall amounts of
0.50 to 1.00 inch are expected for areas along and north of I-20,
with some higher isolated amounts possible.

By tomorrow morning a new upper level disturbance is forecast to
approach our region from the west. Showers and thunderstorms are
expected to initially develop over eastern New Mexico and far
west Texas by tomorrow morning. This rain will then move further
northeast and cover the northwest half of Texas during the day
tomorrow into Friday. Some locally heavy rainfall is forecast over
northwest Texas during this time frame. The first disturbance is
forecast to move northeast of our region by Friday night.
Thereafter, minor upper air disturbances are forecast to cross
north Texas Saturday into Sunday. Additional rainfall is forecast,
especially over the western parts of north Texas, and the WGRFC
will continue to monitor this storm and update as needed.

                    ...PRECIPITATION FORECAST...
For Today into Thursday morning, Mean Areal Precipitation (MAP)
amounts of up to 1.00 inch are forecast for portions of Northeast
and East Texas. Lesser amounts are forecast for areas mainly along
and west of I-35.

For Thursday into Friday morning, MAP amounts of up to 1.00 inch
are forecast for portions of Northwest and West Texas....mainly
for areas along and west of I-35.

For Friday into Saturday morning, MAP amounts of up to 1.00 inch
are forecast for areas along and north of I-20.

For Saturday into Monday morning, MAP amounts of 0.25 to 0.50 inch
are forecast for most of the WGRFC area...excluding the Texas

Drought conditions continue to improve across most of the WGRFC
area. Recent precipitation events have brought drought relief
to many parts of Texas.  In Texas, only about 15% of the state
is experiencing moderate or worse drought, and extreme to
exceptional drought conditions are no longer being observed.
In New Mexico, a little over a third of the state is experiencing
moderate or worse drought (37%), and they also are free from extreme
or exceptional drought conditions. Many of the lakes in Texas
have levels which have risen due to recent rainfall, and some lakes
are full and are releasing water. The rainfall expected over the
next five days over especially the northern half of Texas will be
heavy enough to produce significant runoff, and minor runoff is
expected over the remainder of Texas. Elsewhere over the WGRFC
area no significant runoff is anticipated.

                     ...HYDROLOGIC DISCUSSION...
...Guadalupe Basin...
...Major Flooding...
The recent flood wave generated by very heavy, localized rainfall
around Luling area has moved downstream; now moving through
Gonzales (GNLT2) within moderate flood. This flood wave is
following the heels of the Wimberley flood wave that passed
earlier this week, bringing another rise near major flood.
Downstream at Cuero (CUET2), the high flows from Peach and
Sandies Creeks join which will add to duration and possibly
the crest height. Both these flood waves have caused major
damage along its path of the Blanco and San Marcos River mainstem,
and now moving along the Guadalupe mainstem. These combined waves
are expected to cause major flooding as it moves downstream along
the mainstem through Cuero (CUET2), Victoria (VICT2), and
Bloomington (DUPT2) to the coastal outlet. This event comes in the
wake of an earlier flood wave still moving further downstream; now
cresting through Bloomington (DUPT2).

...Nueces Basin...
...Major Flooding...
Inflows into Choke Canyon Reservoir are on the increase. The Frio
River near Derby (DBYT2) has crested within moderate flood level.
This will cause a rise downstream at Tilden (TIDT2) in to minor
flood late in the week. Choke Canyon is well below the top of the
conservation pool at this time and is increasing only slowly.
On the Nueces River, upstream points at Asherton (ASRT2) and
Cotulla (COTT2) have crested and will remain near steady to slowly
falling. Water is now moving downstream to Tilden (TILT2), which
will be rising into major flood over the next few days.
Three Rivers (THET2) will be rising into moderate flood late in the
week. Inflows into Lake Corpus Christi will once again be on the
increase this week due to these rises. Releases are up slightly to
4120 cfs, which will lead to near steady levels at Bluntzer (CBVT2)
and Calallen (CAAT2). Depending on how much inflow comes into the
reservoir, renewed increases in release are possible at some point
later in the week.

...San Jacinto Basin...
...Major Flooding...
The San Jacinto River basin received additional heavy rainfall
overnight. The West Fork of the San Jacinto river near
Porter (PTET2) is currently in moderate flood category and is
forecast to rise into major flood category. The West Fork near
Humble is in moderate flood category. Peach Creek near Splendora
is forecast to rise into major flood category.

...Colorado Basin...
...Major Flooding...
Heavy rain has fallen over the last 48 hours mainly over the middle
and lower Colorado River Basin.  River stages upstream of La Grange
(LGRT2) have already crested and fallen below criteria. Downstream,
the rivers continue to rise along the mainstem Colorado and its
tributaries.  Some of these locations are forecast to crest at
major flood levels, in particular La Grange and Wharton (WHAT2).

...Trinity Basin...
...Major Flooding...
Heavy rainfall across the entire Trinity River drainage has caused
widespread bankfull, minor, and moderate flood flow conditions.
The Trinity River at Trinidad (TDDT2) is forecast to hit major
flood stage later today.  Downstream near Long Lake (LOLT2) the
river is expected to rise to major flood levels in the next day or
two. At Padera Lake, on the Mountain Creek drainage, the dam is
closely being monitored.  Flood control reservoirs continue to store
flood waters minimizing downstream flood conditions.

...Neches Basin...
...Moderate Flooding...
The Neches River system remains in elevated flow levels with
several locations currently in flood.  The Neches River near
Alto (ATOT2) is at moderate levels.  Nearly every forecast point
within the Neches River system is above flood stage or forecast to
rise above flood stage. Moderate flooding is expected on the lower
Neches River at Weiss Bluff (WBFT2) and Beaumont (BEAT2) as well as
on Pine Island Bayou near Sour Lake (SOLT2). Inflows into B.A.
Steinhagen Lake are on the increase. Therefore event higher flows
than currently forecast are possible downstream at
Town Bluff (TBFT2) and Evadale (EVDT2).

...Brazos Basin...
...Moderate Flooding...
Heavy, localized rainfall (3 to 4 inches) occurred over the last
24 hours in (1) the Possum Kingdom Lake area and (2) further
downstream around Hempstead and Richmond. More widespread lesser
rainfall amounts also occurred between these two locations.
Moderate flooding is occurring or is forecast to occur along
parts of the mainstem Brazos, areas of the Navasota River, the
lower Little River, and a small area on the Leon River. Minor
flooding is also occurring at various locations along the mainstem
Brazos and tributaries from the Possum Kingdom region dowstream
to the Texas Gulf Coast.

...Sabine Basin...
...Moderate Flooding...
Heavy overnight rainfall has caused sufficient runoff to
generate minor and expected moderate flood levels within the
headwaters, Cowleech Fork (GNVT2), South Fork (QLAT2) and
Lake Fork (QTMT2), and along the mainstem Sabine from Greenville
to Toldeo Bend. Toldeo Bend continues to pass inflows with current
releases at 28kcfs; not expected to increase next 24hrs. Moderate
flooding continues on the lower Sabine River Basin through Bon Wier
(BWRT2) and Deweyville (DWYT2) as Toledo Bend Reservoir continues
to pass large inflows.

...San Antonio Basin...
...Moderate Flooding...
Near Falls City, Cibolo Creek (FCTT2) and the San Antonio River
(FACT2) are below flood stage and falling. The San Antonio River
at Goliad (GLIT2) is on the rise and expected to crest in
moderate flood levels later this week.

...San Bernard Basin...
...Moderate Flooding...
Heavy rainfall two nights ago has caused elevated flows on the
San Bernard River. At Boling (BOLT2) and Sweeny (SWYT2) moderate
flooding is occurring or forecast.

...Lavaca-Navidad Basin...
...Minor Flooding...
Heavy rain has fallen over the last 48 hours over the upper and
middle Lavaca and Navidad rivers. Several locations are forecas
to crest at minor flood levels.

...Rio Grande Basin...
...Higher Flow Non-Flood Forecasts...
Releases out of Marte Gomez Reservoir in Mexico are driving a
rise on the Rio Grande near San Benito and Ramirez (SBNT2).
This rise will continue downstream to Brownsville and Matamoros.

...Remainder of WGRFC Basins...
Currently, most rivers are have ongoing flooding conditions and
remain very sensitive to further rainfall. Soil conditions remain
very saturated and any further rainfall will only exacerbate the
ongoing flooding.

The following URLs (all lower case) provide additional graphical
information on current and forecast hydrologic conditions, past and
future precipitation, and drought and climate forecasts.  This
information is provided by a variety of National Weather Service,
NOAA, and private sector entities.

For specific information on river conditions, refer to the AHPS
pages from the local NWS offices at:

The Flood Potential Outlook can be viewed on our webpage at:

The West Gulf River Forecast Center is now on Facebook:

National Precipitation Analysis:

The forecast rainfall amounts (QPF) can be viewed on our webpage at:

The US Drought Assessment:

The latest on Reservoir Information for Texas:



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