Hydrometeorological Discussion
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AGUS74 KFWR 191614
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1114 AM CDT SUN APR 19 2015

                   VALID APRIL 19 THROUGH APRIL 24

...HEAVY RAINFALL HAS ENDED, BUT SOME RAINFALL IS EXPECTED TO
CONTINUE OVER MOST OF THE WGRFC AREA THE NEXT FIVE DAYS...

                  ...METEOROLOGICAL DISCUSSION...
A large low pressure system moved from central Colorado to western
Kansas the past 24 hours.  As the dry line swept east, and as upper
air disturbances moved across Texas, showers and thunderstorms
developed the past 24 hours over the southeast two thirds of Texas and
western Louisiana.  Also, rain and high elevation snow was reported
over portions of southern Colorado and northern New Mexico.  The
heaviest rainfall the past 24 hours was scattered across the state
in small regions, with Rockport TX getting around 2.50 inches.  Over
the next 24 hours, the upper low will weaken and move eastward into
Missouri by late tonight.  During this time period the dry line could
fire up some thunderstorms over east Texas and western Louisiana, but
the heaviest rainfall will occur northeast of the WGRFC area.
Otherwise, drier air will continue to move in from the west, leading
to little in the way of rainfall this afternoon and tonight over most
of our region.

By Monday a ridge of high pressure system will form over
western Oregon. This will put the northern parts of the WGRFC area in
a northwesterly upper air flow. While no major storms are forecast to
move through this flow, a minor storm may produce light precipitation
over northern New Mexico and southern Colorado late tonight into
Monday.  Over the south, an upper air disturbance will move eastward
from Mexico which will move across south Texas Monday into Tuesday
morning.  This disturbance will bring some rain to south Texas,
especially the lower Rio Grande valley. At this point, heavy rainfall
is not expected during this period.

By Wednesday a new low pressure system is forecast to develop off the
California coast.  This will again put the WGRFC region in a
southwesterly upper air flow, which will increase the atmospheric
moisture.  As this low moves slowly eastward later this week there
could be a few periods of showers and thunderstorms Wednesday into
Friday morning over Texas. At this point central Texas is the
most likely location for measurable rainfall, with the best chances
during the afternoon and evening hours. Again, it does not appear that
heavy rainfall will fall.

                    ...PRECIPITATION FORECAST...
For Today into Monday morning, Mean Areal Precipitation (MAP) amounts
of 0.25 inch are forecast for extreme northeast Texas.  Also,  MAP
amounts of 0.25 inch are forecast near the Colorado/New Mexico border.
Lighter amounts of MAP are forecast over the southeastern third of
Texas, most of Louisiana, southern Colorado, and parts of central and
northern New Mexico.

For Monday into Tuesday morning, MAP amounts of 0.25 to 0.50 inch are
forecast for southern Texas, mainly south of a line from Eagle Pass to
south of Corpus Christi.  The heaviest rain will be south of McAllen
TX over northeast Mexico. Lighter amounts of MAP are forecast for the
southern third of Texas, a good part of Colorado, the northeast third
of New Mexico, and the Texas panhandle.

For Tuesday into Wednesday morning, MAP amounts of 0.25 inch are
forecast for parts of central Texas southwest of the DFW metroplex.
MAP amounts of 0.25 of an inch are also forecast over northeast
Mexico.  Lighter amounts of MAP are forecast for much of the WGRFC
region...except for western Louisiana, far west Texas and the southern
two thirds of New Mexico.

For Wednesday into Friday morning, MAP amounts of 0.25 inch or more
are forecast for a good part of northern and central Texas into
northern Louisiana. MAP amounts of 0.25 of an inch are also forecast
across southern Colorado. The heaviest rain, with MAP amounts of
1.00 inch, are forecast north of the WGRFC area over central Oklahoma.
Lighter amounts of MAP are forecast for much of the WGRFC
region...except for far west Texas and the southern two thirds of
New Mexico.

Moderate or worse drought conditions continue across parts of New
Mexico and Texas. In Texas, about a third of the state is experiencing
moderate or worse drought (35%), and about 15% has extreme to
exceptional drought conditions. In New Mexico, about two thirds of the
state is experiencing moderate or worse drought (62%). Lake levels in
the extreme drought areas of Texas are at or near historical lows for
this time of year. Recent precipitation events have brought drought
relief to parts of far west Texas, Deep South Texas and roughly the
southeast third of the state. The rainfall expected over the next five
days over the WGRFC area could produce some minor runoff over south
Texas where soils are moist from recent rainfall. However, no
significant runoff is expected over the northern or western parts of
the WGRFC area.

                     ...HYDROLOGIC DISCUSSION...
...Lavaca-Navidad Basin...
...Moderate Flooding...
Very heavy rains over the entire basin have generated excess runoff
pushing many points into minor flood stage.  The Navidad River at
Strane Park near Edna (LSNT2) and the Tres Palacios River near
Midfield (MTPT2) reached moderate flood stage and are at or near
crest. We will continue monitoring closely for any changes.

...San Bernard Basin...
...Moderate Flooding...
The 5 to 8 inches of rainfall over both Boling basin and Sweeney
have caused both to reach moderate flooding.  Boling has crested
and will begin to fall but stay above moderate for the next couple
of days.  Sweeney with only one observation a day is on the high
end of the moderate scale, but model suggests it is also near its
crest in the next day or so.

...Guadalupe Basin...
...Moderate Flooding...
The major flood at Coleto Creek has receded and Coleto Creek
Reservoir has reduced its releases.  Local rainfall over the past
24 hours caused some action stage rises along San Marcos Creek as
well as the Guadalupe River at Gonzales.  Sandies Creek near
Westhoff has significant water making its way down from the upper
portions of the basin that will cause a rise into minor flood later
today.  Victoria has crested but will rise again to a similar crest
height from routed flow in a few days.

...Nueces Basin...
...Moderate Flooding...
Local heavy rainfall near the Gulf Coast caused the Aransas River
near Skidmore (SKMT2) to rise into moderate flood levels with a
crest near 16 feet overnight. Runoff is also causing the Nueces at
Bluntzer (CBVT2) to rise with a crest near action stage this
evening.

...Neches Basin...
...Minor Flooding...
Localized rainfall brought Mud Creek near Jacksonville back up near
action stage.  Otherwise, no significant changes in the ongoing
flood forecast with widespread minor flooding conditions.
Steinhagen has decided to stay at the 17,000 cfs release for the
time being, keeping Evadale well below 20,000 cfs.  Sour lake looks
to have crested and will begin its slow fall.

...Sabine Basin...
...Minor Flooding...
New rainfall overnight with the fast moving storm to the north
pushed Quinlan back into action stage.  Mineola upper basin water
looks to finally be arriving, however very slowly.  Deweyville
remains unchanged in minor flood below Toledo Bend.

...Colorado Basin...
...Higher Flow Non-Flood Forecasts...
Rainfall over the lower Colorado River Basin has caused a rise at
Wharton (WHAT2) into bankfull levels and should crest this evening
and begin to fall.

...Brazos Basin...
...Higher Flow Non-Flood Forecasts...
Localized heavy rainfall on already elevated river levels pushed a
couple of points into action stage overnight.  Davidson Creek near
Lyons (LYNT2) has risen above bankfull and is expected to crest this
afternoon then fall.  Navasota River near Normangee (NGET2)
continues slow rise as runoff continues. It will remain above
bankfull into next week.  The Brazos at Richmond (RMOT2) has risen
above bankfull and is  expected to remain high for a few days.

...San Antonio Basin...
...Higher Flow Non-Flood Forecasts...
The San Antonio River  at Goliad (GLIT2) has risen  above action
stage and expected to crest near 24 feet late this evening.

...Remainder of WGRFC Basins...
The rest of basins in the area are fairly dry, missing out on much
of the recent beneficial rainfall over the past week.
No significant flooding is expected outside of the areas with
ongoing flooding.

              ...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

STORY

$$




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