Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 211700
1100 AM CST TUE FEB 21 2017



                   ...METEOROLOGICAL DISCUSSION...

A large elongated trough of low pressure is centered over east Texas
this morning, and as part of that trough a closed low pressure system
formed west of Shreveport LA last night.  Widespread rain occurred
over the eastern half of Texas the past 24 hours as the trough
progressed eastward, and most of the rain moved east into Louisiana
last night. The heaviest rainfall the past 24 hours was northwest
of the Houston area where Riverside TX got 2.60 inches. The upper
low will continue to move east over Louisiana today and into
Mississippi tonight.  Some residual showers and thunderstorms
developed near the upper low over east Texas early this morning, and
this rain is moving into southwestern Louisiana now. All the rain
will move east of our region by late today.

A ridge of high pressure is forecast to build over Texas this
afternoon which will bring dry weather conditions to most of the
WGRFC area by tonight.  The ridge will continue to bring dry weather
into Thursday.  The only chance for precipitation will be over
southwestern Colorado.

A weak storm system will be moving quickly out of Utah Thursday
morning and across northern New Mexico and southern Colorado during
the day Thursday.  This disturbance may spread some light rain and
snow into the higher elevations of northwestern New Mexico and
southwest Colorado late Wednesday night into Thursday, but is not
forecast to impact the remainder of the WGRFC area.  As this low
moves over the central plains a cold front will progress southward
across Texas Thursday night into Friday. However, the atmosphere will
be so dry the front will pass without producing any rainfall.

On Friday a strong zonal flow of air is forecast to develop across
the WGRFC area.  This zonal flow is very dry, thus no rainfall is
forecast from Friday through Saturday into Sunday.

                    ...PRECIPITATION FORECAST...
For Today into Wednesday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 inch are forecast for extreme eastern Texas into
Louisiana.  MAP amounts of less than 0.25 of an inch are forecast
over east Texas and Louisiana.

For Wednesday into Thursday morning, no significant MAP amounts are
forecast for the WGRFC area.  MAP amounts of less than 0.25 of an
inch are forecast over southwestern Colorado.

For Thursday into Friday morning, no significant MAP amounts are
forecast for the WGRFC area.  MAP amounts of less than 0.25 of an
inch are forecast over northern New Mexico into southern Colorado.

For Friday into Sunday morning, no significant MAP amounts are
forecast for the WGRFC area.

Rainfall from the past 48 hours and from last week has no doubt
improved the soil moisture conditions across much of Texas. The
last U.S. Drought Monitor for Texas showed the area considered to be
abnormally dry was at 12%.  Also, 4% of Texas was experiencing
moderate drought conditions and 1% was in severe drought. In New
Mexico the drought monitor shows around 12% of the state experiencing
abnormally dry conditions, with 2% remaining in moderate drought. The
rainfall forecast the next five days will not produce new or
additional runoff over the WGRFC area.

                     ...HYDROLOGIC DISCUSSION...
...Lavaca-Navidad Basin...
...Minor Flooding...
Many of the sites did respond to the rainfall, but amounts stayed too
light to generate any significant flooding.  Expect out of bank flow
but no impacts for the area.

...Guadalupe Basin...
...Minor Flooding...
Widespread light rain with locally heavy amounts occurred over parts
of the Guadalupe River Basin.  The lower Guadalupe River at DuPont
(DUPT2) is forecast to crest above flood stage.  The remainder of
the Guadalupe is expected to remain below flood criteria.

...Neches Basin...
...Minor Flooding...
Most locations along the river continue to slowly rise after
yesterday`s rain event. The only location over flood stage today is
the mainstem Neches near Diboll. The river should start falling later
this week.

...Sabine Basin...
...Minor Flooding...
Minor flooding continues today on Rabbit Creek and the mainstem of the
Sabine River has risen in response to the moderate rainfall event this
last weekend. No significant impacts are expected at this time. Side
channels should recover back to baseflow before the next rain event
which is not expected until early next week. Reservoirs are still
relatively full.

...San Jacinto Basin...
...Higher Flow Non-Flood Forecasts...
Local rainfall of around 2 inches did cause some responses, but no
flooding is expected.

...San Bernard Basin...
...Higher Flow Non-Flood Forecasts...
San Bernard did respond to the local runoff, but the amounts were not
high enough to generate any major rises.  East Bernard may reach minor
but all points should stay below minor flood.

...Trinity Basin...
...Higher Flow Non-Flood Forecasts...
Last weekends rainfall generated above average inflows into Lake
Livingston.  Expect Lake Livingston to pass these inflows downstream
where above bank stages may occur late week at Livingston (LVDT2) and
Moss Bluff (MBFT2).

...Brazos Basin...
...Higher Flow Non-Flood Forecasts...
In the upper portion of the Brazos Basin, heavy rains above Possum
Kingdom Reservoir has increased inflows to the lake and the dam has
started to release water. No impacts are expected from this release
since the amount is relatively routine, though they may need to
maintain releases for a few days this time. On the lower end of the
river, the area near Sommerville has higher then normal flows and the
mainstem is running above normal from Hempstead to Richmond. All
these flows should return to normal before the next rain event early
next week.

...San Antonio Basin...
...Higher Flow Non-Flood Forecasts...
Widespread light rain with locally heavy amounts recently occurred over
parts of the San Antonio River Basin.  River levels located in the
upper part of the river basin have crested and are now falling.  For
the middle and lower part, the San Antonio River and its tributaries
continue to rise.  These locations are forecast to crest below flood
stage.  River levels will remain at higher than normal flow levels.

...Remainder of WGRFC Basins...
Most of Texas saw some beneficial rain this weekend which will keep
soils saturated for a bit, but with no heavy rain in the forecast no
flooding is expected in the forecast period.

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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