Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 011635
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1135 AM CDT SUN MAY 1 2016

                      VALID MAY 1 THROUGH MAY 6

...AN ACTIVE WEATHER PATTERN WILL CONTINUE ANOTHER TWO DAYS BEFORE A
DRYING TREND BEGINS BY THE MIDDLE OF THE WEEK...

                  ...METEOROLOGICAL DISCUSSION...
Another weather producer is beginning to affect the WGRFC area this
morning and will continue into the first part of the week. This will
result in another round of showers and thunderstorms, as well as some
periods of snowfall in the higher elevations of New Mexico and
Colorado.

The system which brought rain the past few days is located over
Nebraska this morning. This low brought precipitation to east Texas
and western Louisiana Saturday morning before moving east.  Then
new showers and thunderstorms developed Saturday night along the
middle and upper Texas Gulf coast along a cold front. These
thunderstorms continue from near Orange TX into southern Louisiana
now.  The heaviest rain the past 24 hours occurred over extreme
southeast Texas into southern Louisiana where the region from Lake
Charles to Oberlin LA received 5.00 to over 7.00 inches. In Texas
Beaumont received around 2.50 inches.  Mostly dry conditions occurred
Saturday afternoon and night over the remainder of Texas.

Meanwhile, a new low pressure system has developed over Arizona.
This low has already spread additional precipitation over New Mexico
and Colorado.  Additional showers and thunderstorms will be spreading
from southwest Texas and the panhandle this afternoon into central
Texas tonight. Also, the cold front is forecast to stall today over
southeast Texas.  This may result in additional scattered showers and
thunderstorms near the Gulf coast today into Monday, especially
from roughly Houston and Lake Charles into southern Louisiana.  The
Arizona storm system will begin to weaken and will shift quickly east
by Monday, and a trough will move across Texas.  As this occurs there
will be some residual rainfall over the southeastern half of Texas
and western Louisiana Monday into early Tuesday morning.  A final
upper air disturbance is forecast to move across Oklahoma and north
Texas Tuesday night and Wednesday morning, but with little or no
precipitation.

Drier conditions will finally return to the region Wednesday through
Thursday as a ridge of high pressure develops over the Rocky
Mountains and moves eastward over Texas.

By Friday morning a new low pressure system will be developing over
southern California.  Ahead of this low, moisture is forecast to
begin flowing northward.  This may result in some precipitation over
parts of New Mexico and Colorado by Friday morning.

                    ...PRECIPITATION FORECAST...
For Today into Monday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 of an inch or more are forecast over southeast
Texas into Louisiana, as well as over much of southern Colorado,
northeast New Mexico, and southwest Texas. The heaviest rain, with
MAP amounts of 2.00 inches, are forecast for southern Louisiana
from the lower Sabine River eastward. MAP amounts of less than 0.25
of an inch are forecast over most of the remaining sections of the
WGRFC area.

For Monday into Tuesday morning, MAP amounts of 0.25 of an inch or
more are forecast over roughly the southeast half of Texas, most of
Louisiana, as well as over a few spots over southwestern Colorado.
The heaviest rain, with MAP amounts of 1.00 inch, are forecast for
the lower Sabine River eastward into southern Louisiana.  MAP amounts
of less than 0.25 of an inch are forecast over the southeast two
thirds of Texas and Louisiana, the northwest half of New Mexico and
western Colorado.

For Tuesday into Wednesday morning, no significant MAP amounts are
forecast for the WGRFC area.  MAP amounts of less than 0.25 of an
inch are forecast over deep south Texas, over a good part of New
Mexico and southern Colorado, and western Texas.

For Wednesday 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 the northeast half of New Mexico and Colorado,
and far western Texas.

Soil moisture has rebounded this past 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 significant additional runoff into the rivers over
southeastern Texas and western Louisiana because those areas
have saturated soils.  Elsewhere, only minor amounts of runoff are
expected.

                     ...HYDROLOGIC DISCUSSION...
...Trinity Basin...
...Major Flooding...
Heavy rainfall recently occurred over the middle and 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).  Downstream, 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...
Recent rainfall in the upper half of the Neches River Basin has  pushed
numerous forecast points into minor and moderate flood stage.  The most
significant precipitation occurred near Palestine where 7+ inches was
observed.  This is driving the Neches River near Alto with a forecast
to crest at major flood stage later this week.  Heavy rainfall has also
been occurring this morning over the lower Neches near Beaumont. This
rainfall is beginning to move east of the area.

...Sabine Basin...
...Major Flooding...
Widespread heavy rain fell across the upper Sabine over the past day
and a half, which has led to several major flood forecasts. Lake Fork
Creek at Quitman and Rabbit Creek at Kilgore crested in major flood
yesterday but have both fallen below major flood levels as of this
morning. The 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.

...San Jacinto Basin...
...Moderate Flooding...
Heavy rains over the past day and a half caused Peach Creek at
Splendora to quickly climb into moderate flood early this morning.
Several other sites have or will reach action stage from this rainfall
as well.

...Brazos Basin...
...Minor Flooding...
Higher than normal flows continue on the lower Brazos River due to
recent heavy rainfall,. 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.

...San Bernard Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rain that fell recently has slowed the recession within action
stage for Sweeny (SWYT2) but should be below action stage later
today.

...Colorado Basin...
...Higher Flow Non-Flood Forecasts...
Colorado River at Wharton (WHAT2) remains in action stage and in
recession.

...Remainder of WGRFC Basins...
Unsettled weather is expected over the next 2 days.
Location and amounts of rainfall will be critical in determining
river response, but the heaviest rainfall is expected on Monday
over southeastern portions of Texas.

              ...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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