Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 271807
107 PM CDT FRI MAY 27 2016

                     VALID MAY 27 THROUGH JUNE 1


                  ...METEOROLOGICAL DISCUSSION...
An upper level low pressure system is located over eastern Colorado
this morning.  Upper air disturbances ahead of this low brought
widespread showers and thunderstorms to most of Texas, and these
thunderstorms will continue into the beginning of the Memorial Day
Holiday Weekend. Low level moisture and instability remains
plentiful, resulting in locally very heavy rainfall. Parts of
central, south central and southeast Texas received in excess of 4.00
inches of rain the past 24 hours, with amounts of over 10 inches from
Lake Somerville through Brenham to The Woodlands.  A maximum rainfall
of 19 inches occurred near Brenham.  As the upper low moves out of
Colorado into Kansas this afternoon and tonight, drier air will move
into Texas from the west.  The last of the thunderstorms now over
east Texas will move east into Louisiana tonight. Localized flooding
rainfall is forecast for today for the eastern third of Texas before

The region should get a break from the rainfall for most of Saturday.
But yet another storm system will be setting up to bring more rain
into WGRFC`s area later in the weekend into early next week.  By
Saturday night the next low pressure system will be forming south of
San Francisco CA.  Moisture well out ahead of this low will move up
the Rio Grande, and this moisture will combine with an upper air
disturbance to produce some rain over southwest Texas and northern
Mexico.  This disturbance will spread up into north Texas Sunday,
bringing a chance for light precipitation.

By Monday morning the upper low will move into Arizona.  This will
result in the dryline becoming active again in western Texas later on
Sunday into Monday. Then this low will weaken by Tuesday over western
New Mexico, but portions of northern and western Texas areas could
continue to see pockets of rainfall, especially along and near the
Red River where the strongest thunderstorms are expected.

The upper air disturbance is forecast to move over the Texas
panhandle Wednesday.  Therefore more rainfall is possible over Texas
Wednesday into Thursday.

                    ...PRECIPITATION FORECAST...
For Today into Saturday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 inch or more are forecast for northern and eastern
Texas into western Louisiana.  The heaviest rain, with MAP amounts
of 2.00 inches, are forecast for east central and extreme northeast
Texas and northwest Louisiana.  MAP amounts of less than 0.25 inch
are forecast for southern Colorado, northern New Mexico, and the
eastern two thirds of Texas.

For Saturday into Sunday morning, MAP amounts of 0.25 to 0.50 inch
are forecast for west and southwestern Texas.  MAP amounts of less
than 0.25 inch are forecast for southern Colorado, northern and
eastern New Mexico, most of Texas, and western Louisiana.

For Sunday into Monday morning, MAP amounts of 0.25 to 0.50 inch
are forecast for western and northern Texas.  MAP amounts of less
than 0.25 inch are forecast for southern Colorado, the northeastern
two thirds of New Mexico, and most of Texas.

For Monday into Wednesday morning, MAP amounts of 0.25 inch or more
are forecast for most of Texas.  The heaviest rain, with MAP
amounts of 2.00 inches, are forecast for the Red River valley around
Childress.  MAP amounts of less than 0.25 inch are forecast for
most of the WGRFC area of responsibility.

Soils continue to be  moist across the majority Texas, especially
the eastern half. Only 3% of Texas is categorized as abnormally dry,
with no moderate or greater drought noted. Over New Mexico, 83%
of the state is abnormally dry, and 37% remains in the moderate
drought category.  With soils being so wet, runoff is expected from
the forecast rainfall over northern and eastern Texas.  Over the
remainder of the WGRFC area little runoff will occur.

                     ...HYDROLOGIC DISCUSSION...
...Colorado Basin...
...Major Flooding...
Pockets of heavy rainfall produced widespread rises and river flooding
downstream of the Austin area.  Major Flooding is expected from Bastrop
to Wharton.  Any rainfall over the next several days will produce

...Trinity Basin...
...Major Flooding...
Heavy rainfall has fallen over the last 24 hours over the lower Trinity
River Basin, especially around Lake Livingston.  Bedias Creek near
Madisonville (MDST2) is rising rapidly and is at major flood levels.
Madisonville is forecast to crest around 27 feet this evening.  Lake
Livingston is also rising due to local inflow in addition to upstream
routed water from Bedias Creek and the mainstem Trinity.  Lake
Livingston is currently increasing their releases to pass this inflow.

Downstream, the lower Trinity and tributaries are currently rising due
to heavy rainfall along with releases from Lake Livingston.  The
Trinity River at Liberty (LBYT2) is currently forecast to crest 29 to
29.5 feet (major flood level) early next week.

For the upper and middle Trinity, higher than normal flows along with
minor flood levels are occurring at several locations.

...Brazos Basin...
...Major Flooding...
Heavy overnight rainfall across much of the Brazos River system has
generated higher, bankfull and minor flood flows within area
tributaries and moderate to major flood conditions along the mainstem.
Persistent overnight rainfall with intensities of 1 to 2.5 inches per
hour with accumulated totals of 8 to 12 plus inches widespread with
localized amounts up to 16 inches.

As a result, the Brazos mainstem from Washington through Hempstead
(HPDT2) and Richmond (RMOT2) to Rosharon (ROST2) is or will
experience moderate and major flood levels through the weekend into
early next week.

...Guadalupe Basin...
...Moderate Flooding...
Widespread rainfall during the previous 24 hours will cause minor
flooding at a few forecast points. Victoria (VICT2) will is
forecast to crest in the minor flood category early next week. Also
Bloomington  (DUPT2) will fluctuate at moderate flood levels from
this additional rainfall. Minor flooding is also forecast for
Plum Creek at Luling (LULT2) until later this weekend.

...Neches Basin...
...Minor Flooding...
Widespread rainfall during the previous 24 hours has caused minor
flooding at 8 forecast points. Three additional locations are tracking
to crest at action stage. The highest concentration of precipitation
fell across the western edge of the basin. Widespread areas of 3-4
inches fell across the eastern basin with a with maximum value of 6
inches recorded on the border of the ROKT2 and DIBT2 basins.

The forecast points in the Neches basin are slow responding and will
crest in the next two to three days. The current forecasts are still
QPF driven with an average of 0.5 inches of additional precipitation
over the course of Friday afternoon; however, the majority of
precipitation driving the forecast is observed and will materialize and
route downstream over the next week. The current releases from Rayburn
were cut back from 13,300 cfs to 8,600 cfs. Releases from Dam B have
been held steady at 15,800 cfs. USACE will be regulating the river to a
target flow of 20,000 cfs at Evadale.

...San Jacinto Basin...
...Higher Flow Non-Flood Forecasts...
Heavy rainfall occurred in the San Jacinto basin overnight.  Widespread
moderate to major flooding is forecast across the basin and additional
rainfall is forecast.

...Remainder of WGRFC Basins...
The remaining river systems across the WGRFC area remain relatively wet,
especially the eastern half of Texas, and additional rainfall
expected within the next 5 days will likely generate river responses
which could lead to more river action level and flood level flows.

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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