Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 261550
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1049 AM CDT FRI AUG 26 2016

                  VALID AUGUST 26 THROUGH AUGUST 31

...HEAVY RAINS EXPECTED ALONG THE TEXAS COAST THIS WEEKEND...

                  ...METEOROLOGICAL DISCUSSION...

A cluster of showers and thunderstorms developed early this morning
from Candelaria down to Presidio, producing some minor flooding
across the basin. This activity has decreased in intensity the past
hour or so, however precipitation is expected to continue throughout
the day. Abundant moisture from the Pacific, is expected to continue
moving across the Rio Grande Valley through this weekend. As a
result, higher than normal flows and/or minor flooding is possible.

Elsewhere, showers and thunderstorms associated with an easterly
wave will impact portions of the southeast Texas coast through the
weekend. Some scattered showers have already developed along the
upper Texas coast this morning, however the main activity is
offshore for now. One thing to note, there is a considerable
amount of moisture flowing in from the Gulf of Mexico, and this
should continue for the next few days. Therefore, the threat is
high for very heavy rainfall, flash flooding and minor flooding to
occur over the coastal areas this weekend. Rainfall amounts of 4-6
inches (isolated amounts up to 8 inches) are possible along the
coastal areas of Texas and Louisiana, mainly Saturday through
Monday.

By early next week, a ridge of high pressure will build back
westward once again and deliver mostly dry conditions to most
of Texas...excluding the Texas coast. Although a ridge of high
pressure is forecast to dominate the area next week, there is
still a lot of uncertainty on the development (if any) of an
easterly wave over the Gulf of Mexico and a tropical wave
moving through the Caribbean Sea. We will continue to monitor
the forecast models over the weekend and update accordingly.

                    ...PRECIPITATION FORECAST...
For Today into Saturday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 to 0.50 inch are forecast for portions of Southeast,
East Texas and the West Texas.

For Saturday into Sunday morning, MAP amounts of up to 1.00 inch
are forecast for the coastal areas of Texas and Louisiana. Lesser
amounts are forecast for West Texas.

For Sunday into Monday morning, MAP amounts of up to 1.00 inch
are forecast for the coastal area of Texas and Louisiana.

For Monday into Wednesday morning, MAP amounts of up to 1.00 inch
are forecast for the coastal area of Texas and Louisiana, Deep
South Texas.

After the widespread rain the past seven days over parts of New
Mexico and Texas, drought conditions have eased somewhat. The U.S.
Drought Monitor has categorized Texas as 29% abnormally dry, with
less than 1% in severe drought. Over New Mexico, 88% of the state is
abnormally dry, and 24% remains in the moderate drought category.
The showers and thunderstorms forecast this week will keep more
serious drought conditions from developing over the WGRFC region,
while many sections continue drought-free.  Since topsoil has become
moister, some runoff is possible where the heaviest rain is
forecast. However, as the weather dries out some this week most of
the runoff will be insignificant across the majority of the WGRFC
area.

                     ...HYDROLOGIC DISCUSSION...
...Guadalupe Basin...
...Moderate Flooding...
Lower end of the Guadalupe River continues to move flood waters to
the  Gulf. The Guadalupe at Victoria (VICT2) continues to fall
rapidly and Bloomington (DUPT2) has crested but will remain above
flood stage for several more days.

...San Antonio Basin...
...Moderate Flooding...
The flood wave generated near the San Antonio area has finally
passed the last forecast point on the river system and flooding
should come to a close over the weekend. New rises are possible,
though, as rain returns to the region later this weekend.

...Rio Grande Basin...
...Minor Flooding...
Heavy localized rains overnight have generated several waves of
water causing a few locations to rise above flood stage. The first
wave from the Rio Conchos is affecting the Presidio area and
another wave from Terlingua Creek has entered the mainstem near
Castolon and is heading for the Big Bend region. Only monir flooding
is expected at this time. Reservoirs on the Mexican side of the
river continue to slowly fill from all the recent rainfall activity.

...Trinity Basin...
...Minor Flooding...
Out of bank to minor flooding continues in the upper West Fork of
the Trinity River from releases from Bridgeport, but should be
coming to a close in a day or so as the lake reduces releases.

...Brazos Basin...
...Higher Flow Non-Flood Forecasts...
All locations continue to recede as flood waves move into reservoirs
or into the Gulf. New rises are possible as precipitation returns to
the area later this weekend.

...Nueces Basin...
...Higher Flow Non-Flood Forecasts...
Flooding has ended on the Nueces River at Three Rivers (THET2) and
all locations below Tilden are falling. Smaller waves are working
their way down the mainstem of the Nueces and will cause higher than
normal flow through the area over the next few days. Additional
rises likely with precipitation returning to the region over the
weekend.

...Remainder of WGRFC Basins...
Soils are back to being fairly saturated over large areas of the
WGRFC region. With additional rainfall expected over the weekend,
new rises are expected in many of our river systems over the next 5
days.


              ...SUPPLEMENTARY GRAPHICAL INFORMATION...
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:
http://water.weather.gov/ahps/

The Flood Potential Outlook can be viewed on our webpage at:
http://www.srh.noaa.gov/wgrfc/?n=wgrfcfop

The West Gulf River Forecast Center is now on Facebook:
http://www.facebook.com/US.NationalWeatherService.WGRFC.gov

National Precipitation Analysis:
http://water.weather.gov/precip/

The forecast rainfall amounts (QPF) can be viewed on our webpage at:
http://www.srh.noaa.gov/wgrfc/?n=wgrfcqpfpage

The US Drought Assessment:
http://www.cpc.ncep.noaa.gov/products/Drought

The latest on Reservoir Information for Texas:
http://www.waterdatafortexas.org/reservoirs/statewide

MCCANTS


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