Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 041718
1118 AM CST SUN DEC 4 2016



                  ...METEOROLOGICAL DISCUSSION...

Low pressure is forecast to move northeastward toward southwest
Texas by tomorrow morning allowing significant rainfall to continue,
impacting portions southeast and east Texas the most, through Monday
afternoon, with widespread lighter amounts elsewhere.

Storm total rainfall amounts for this event are expected to approach
13.00 inches in far southeast Texas. As of this morning, there have
been reports of 5.00 to 8.00 inches with local amounts of over 10.00
inches in southeastern Texas, with another 2.00 to 3.00 inches
expected into Monday. With this much rainfall, widespread minor
flooding has been reported...and will continue, with some isolated
moderate flooding. However, widespread moderate and major flooding is
not expected.

By tomorrow night and Tuesday morning, the upper level low will begin
to weaken and move to the northeast across Texas. This will put an
end to the rainfall across the WGRFC area.

After a relatively dry day Tuesday, a strong cold front is forecast
to move across Texas on Wednesday.  This front may create some
showers and thunderstorms along and ahead of the front, but due to
the speed of these storms heavy rainfall is not expected.  High
pressure will move over most of the WGRFC area on Thursday so most of
the precipitation will end and cold weather will set in.

                    ...PRECIPITATION FORECAST...
For Today into Monday morning, Mean Areal Precipitation (MAP)
amounts of  amounts of 1.50 to 2.00 inches are forecast for the
middle and upper Texas Gulf coast into east central Texas and west
central Louisiana.  Lesser amounts of less than 0.25 of an inch are
forecast for most of the WGRFC area except for New Mexico, Colorado,
and northwest Texas.

For Monday into Tuesday morning, MAP amounts of 1.00 to 1.50 inch
are forecast over extreme southeast Texas and much of southwestern

For Tuesday into Wednesday morning, no significant MAP amounts are
forecast for the WGRFC area.

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

The rainfall early in November helped to improve (slightly) the
ongoing drought conditions across the WGRFC area. The rainfall
which is ongoing will no doubt bring additional drought relief. In
Texas, the areas considered to be abnormally dry is at 34%. Also,
14% of Texas is experiencing moderate drought conditions and 3% is
in severe drought, primarily over extreme east Texas. In New Mexico,
around 54% of the state is experiencing abnormally dry conditions,
with 5% remaining in moderate drought. The heaviest rainfall the
next 5 days will fall over east and southeast Texas, which also
happens to be the driest part of Texas.

                     ...HYDROLOGIC DISCUSSION...
...Guadalupe Basin...
...Minor Flooding...
Heavy rains in the Guadalupe River basin over the past 48 hours have
caused minor rises along portions of the Guadalupe. An additional
1-3 inches of rain is possible through Monday, which could worsen
flooding in the area. Several sites in the middle and lower part of
the basin have reached or are forecast to reach action stage, and
the Guadalupe River at du Pont Plant near Bloomington (DUPT2) is
expected to reach minor flood levels by the middle of the week due
to routed flows.

...Neches Basin...
...Minor Flooding...
Rainfall over the last 24 hours has caused overbank to minor levels
of flooding across the lower Neches basin.  If additional rainfall
occurs it will aggravate the existing flooding.

...San Antonio Basin...
...Moderate Flooding...
Heavy rainfall overnight in the San Antonio area has caused creeks
to swell rapidly.  Salado Creek and the San Antonio mainstem in and
around San Antonio city reached moderate to major flood levels in
the past 24 hours.  Elmendorf (ELMT2) on the mainstem has crested
above moderate flood levels.  Cibolo Creek at Sutherland  Springs
(SUPT2) and near Falls City (FCTT2) are also expected to rise into
moderate flood levels today.

...San Jacinto Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rainfall has caused some minor runoff events in the San
Jacinto basin.  Most notably Lake Creek at Sendera Road (FCWT2) near
the Conroe area is above action stage but is expected to crest with
the next couple of days with a double crest still within action

...San Bernard Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rain over the past 48 hours will cause San Bernard River near
East Bernard (EBBT2) to reach action stage early this week.
Additional rainfall is expected through Monday, so additional rises
are possible.

...Lavaca-Navidad Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rains over central and southeast Texas have caused some minor
runoff responses to creek and rivers in the area. The West Mustang
Creek near Ganado (GNDT2) is expected to reach action stage in the
next day or so.

...Brazos Basin...
...Higher Flow Non-Flood Forecasts...
With moderate rains in portions of the Brazos, Davidson Creek near
Lyons (LYNT2) will crest slightly above action stage this evening.

...Remainder of WGRFC Basins...
Widespread rainfall has been falling over central, southeast and far
east Texas. So far the rainfall has been beneficial to the portions
of Texas that were beginning to suffer from drought conditions.
Some bankfull to moderate flooding has been occurring from the past
two day rainfall totals. Additional rains are anticipated this
evening into Monday and may expand the number of locations in minor
flood criteria.  No additional moderate flooding is expected at this
time,  but any headwater areas receiving amounts beyond 3 to 5
additional inches could be affected.

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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