Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 301643
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1143 AM CDT SAT APR 30 2016

                    VALID APRIL 30 THROUGH MAY 5

...AN ACTIVE WEATHER PATTERN WILL CONTINUE INTO EARLY NEXT WEEK
BEFORE A DRYING TREND BEGINS BY THE MIDDLE OF THE WEEK...

                  ...METEOROLOGICAL DISCUSSION...
A series of weather producers will continue to affect the WGRFC area
into the first part of next week. This will result in periods of
showers and thunderstorms, as well as some periods of snowfall in the
higher elevations of New Mexico and Colorado.

The first system is located over northwest Kansas this morning. This
low brought precipitation to much of New Mexico and Colorado the
past 24 hours.  Further east, a dryline became active across central
Texas. Numerous showers and thunderstorms developed across west
Texas Friday morning which increased Friday afternoon over central
Texas, then moved across east Texas and western Louisiana Friday
night into early this morning.  The heaviest rain occurred over east
Texas where Marshall received 8.00 to over 9.00 inches. Palestine TX
received just under 8.00 inches and Paris TX got 7.50 inches.  The
upper level low will lift northeast into southern Nebraska by this
evening and most of the showers and thunderstorms will move east of
our region.  Mostly dry conditions are expected this afternoon and
evening.

Meanwhile, a new low pressure system will be digging over Arizona on
Sunday morning.  This low will spread additional precipitation over
New Mexico and Colorado starting tonight, with showers and
thunderstorms spreading into west Texas Sunday afternoon into
Monday.  Also, a cold front is forecast to move into southeast Texas
and will stall.  This may result in additional scattered showers and
thunderstorms near the Gulf coast later Sunday, especially from
roughly Houston and Lake Charles into southern and central
Louisiana.  The main system will begin to weaken and will shift
quickly east by Monday, and as the final trough moves across Texas
there will be some residual rainfall over the southeastern half of
Texas and western Louisiana Monday into Tuesday morning.

Drier conditions will finally return to the region later Tuesday
and Wednesday into Thursday morning as a ridge of high pressure
develops over the Rocky Mountains.

                    ...PRECIPITATION FORECAST...
For Today into Sunday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 of an inch or more are forecast over southeast Texas
into Louisiana, as well as southern Colorado into northwest and
north central New Mexico. The heaviest rain, with MAP amounts of 2.00
inches, are forecast along the lower Sabine River into southwest
Louisiana.  MAP amounts of less than 0.25 of an inch are forecast
over the southeast quarter of Texas, the northern two thirds of New
Mexico and most of Colorado.

For Sunday into Monday morning, MAP amounts of 0.25 of an inch or
more are forecast from southwest Texas across central and east
Texas into Louisiana, as well as over much of southern Colorado and
the northern third of New Mexico. The heaviest rain, with MAP amounts
of 1.00 inch, are forecast for southeastern Texas into southern
Louisiana.  MAP amounts of less than 0.25 of an inch are forecast
over most of Texas and Louisiana, the northeastern three quarters of
New Mexico and Colorado.

For Monday into Tuesday morning, MAP amounts of 0.25 of an inch or
more are forecast over roughly the southeast half of Texas,
Louisiana, as well as over a few spots over northern New Mexico into
southwestern Colorado. The heaviest rain, with MAP amounts of 1.00
inch, are forecast for the upper Texas Gulf coastline into southern
Louisiana.  MAP amounts of less than 0.25 of an inch are forecast
over a good part of Texas and Louisiana, the northwest half of
New Mexico and western Colorado.

For Tuesday into Thursday morning, MAP amounts of 0.25 of an inch or
more are forecast over a few spots over southern Colorado and
northeastern New Mexico.  MAP amounts of 0.25 to 1.00 inch are
forecast over the Gulf of Mexico southeast of Brownsville TX.  MAP
amounts of less than 0.25 of an inch are forecast over southeast and
deep south Texas into southern Louisiana, over a good part of New
Mexico and Colorado, and western Texas.

Soil moisture has rebounded this week as an active weather pattern
has produced abundant rain.  Soils are now very moist across a
good part of the state, especially the eastern portions. Texas is now
categorized as being 13% abnormally dry, with 2% in the moderate
drought category. These dry areas are confined to the Texas panhandle
and the far western portions of the state, with the remainder of the
state free of drought. Over New Mexico, almost the entire state
remains in the abnormally dry category, and 44% is in moderate
drought. The rainfall which is forecast over the next 5 days will
produce additional runoff into the rivers over the southeastern
third of Texas and western Louisiana.  Significant runoff can be
expected because those areas have saturated soils.  Elsewhere, only
minor amounts of runoff are expected.

                     ...HYDROLOGIC DISCUSSION...
...Trinity Basin...
...Major Flooding...
Heavy rainfall occurred over the last 24 hours over the lower Trinity
River Basin.  Both Cedar Creek Reservoir and Lake Livingston are
currently passing inflow from upstream runoff.  These releases are
generating moderate flood levels on the mainstem Trinity River at
Trinidad (TDDT2) and Long Lake (LOLT2).  The Trinity River at Liberty
(LBYT2) is forecast to rise into major flood levels by the middle of
next week.

For the upper Trinity, water supply reservoirs are passing inflows to
maintain their conservation pools.  Flood control reservoirs are also
evacuating their flood pools.  This is keeping the mainstem of the
Trinity and its tributaries well above normal.

...Neches Basin...
...Major Flooding...
Rainfall observed overnight in the upper half of the Neches basin has
pushed numerous forecast points into minor and moderate flood stage.
The most significant precipitation occurred near Palestine where 7+
inches was observed and is driving one forecast point to Major flood
stage. Neches River near Alto is forecast to crest at Major flood
stage mid-week due to routed flow from upper basin runoff. As of
Saturday AM, the lower half of the basin was still receiving
precipitation. Observed precipitation and QPF is driving several of
the points on the lower end of the basin to minor flood stage.

...Sabine Basin...
...Major Flooding...
Widespread heavy rain fell across the upper Sabine over the past 24
hours, which has led to several major flood forecasts. Lake Fork Creek
at Quitman and Rabbit Creek at Kilgore reached major flood stage this
morning, and Sabine River at Gladewater is expected to reach major
flood levels early next week due to the locally heavy rainfall and
routed flows. Sabine River at Longview and Beckville are expected to
climb into moderate flood from the routed flow, but points beyond
that along the mainstem river should only reach minor flood or
action stage, including sites downstream of Toledo Bend.

...Brazos Basin...
...Minor Flooding...
Higher than normal flows continue on the lower Brazos River due to
last weeks heavy rainfall, and the additional rainfall that occurred
over the past 24 hours. Navasota River at Easterly (EAST2) and near
Normangee (NGET2) are the only sites in this basin that are forecast
to go into minor flood from the recent rainfall. The other 6 sites on
the lower end of the Brazos river basin will only reach action stage.

...San Jacinto Basin...
...Higher Flow Non-Flood Forecasts...
The three sites within the San Jacinto basin that were expected to
climb into action stage yesterday have been dropped because the
rainfall amounts did not materialize.

...San Bernard Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rain that fell over the past 24 hours has slowed the recession
within action stage for SWYT2, but other points along the San Bernard
River basin appear to remain below criteria.

...Colorado Basin...
...Higher Flow Non-Flood Forecasts...
Colorado River at Wharton (WHAT2) remains in action stage but is slowly
falling. The widespread rainfall that fell over the past 24 hours has
had little effect on the Colorado River basin.

...Remainder of WGRFC Basins...
Unsettled weather is in the forecast for at least the next 4 days.
Location and amounts of rainfall will be critical in determining river
response, but the heaviest rainfall is expected on Monday.

              ...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

STORY

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