Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 201624
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1123 AM CDT SAT SEP 20 2014

               VALID SEPTEMBER 20 THROUGH SEPTEMBER 25

...WIDESPREAD RAIN EXPECTED THE NEXT FEW DAYS, WITH SIGNIFICANT
RAINFALL FORECAST OVER PORTIONS OF NEW MEXICO AND WEST TEXAS...

                   ...METEOROLOGICAL DISCUSSION...

Weak upper air disturbances, combined with an old frontal boundary,
have kept scattered to numerous showers ongoing across most of the
WGRFC area the past few days. In general, upper level disturbances
combined with abundant atmospheric moisture favor continued
thunderstorms and showers through the weekend, with a gradual
decrease in the precipitation early next week.

The other focus for rainfall has been and continues to be with the
remnants of Hurricane Odile slowly moving along the Texas/New Mexico
border.  Over the next several days, the remnants of Odile are
expected to move slowly northeast into the Texas panhandle then drop
southward toward the Permian Basin by Sunday morning. With all the
moisture in place over the area, the widespread rain will
continue over southeastern New Mexico into west Texas and the Texas
panhandle through today. Flash flooding will continue to remain the
greatest concern, along with developing minor and possible moderate
flooding on the Pecos River during the next two days. Rainfall
is also expected into early next week, especially over west central
and southwest Texas, depending upon the future track of Odile`s
remnants. Since these remnants should be weakening over west Texas
Sunday, mainly light to moderate rain is expected over this part of
Texas and southeast New Mexico.  We will continue to monitor the
progress of this storm.

By Monday a weak cold front is forecast to move into northern and
eastern Texas. At this point significant rainfall is not expected
with the frontal boundary as the remnants of Odile eventually weaken
further over west Texas.  Behind the front, drier air will be ushered
in, so rainfall will decrease further across Texas by Wednesday
morning.

                    ...PRECIPITATION FORECAST...

For Today into Sunday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 to 1.00 inch are forecast to fall over southeastern
New Mexico and far west Texas with the heaviest amounts possible
north of I-20 from Odessa to Lubbock and eastward toward Stamford,
Texas.

For Sunday into Monday morning, MAP amounts of 0.25 to 1.00 inch are
forecast for most of New Mexico with the heaviest amounts over the
Pecos River basin to points south of Red Bluff Dam along the I-20
corridor in far west Texas.

For Monday into Tuesday morning, MAP amounts of 0.25 to 0.50 of an
inch are forecast for an area in the upper Rio Grande valley from
Alamogordo north to Albuquerque.

For Tuesday into Thursday morning, no significant MAP amounts are
forecast for the WGRFC area.

Drought persists but is slowly improving over Texas and New Mexico.
Statewide, New Mexico has no areas of exceptional drought, while less
than 2% of Texas remains in exceptional drought. Severe drought
conditions are impacting less than 40% of New Mexico and 35% of
Texas.  No doubt the rainfall forecast the next 5 days will
further alleviate some of the ongoing drought. Runoff is expected
across far west Texas, as well as over southeastern New Mexico for
the few days.  Runoff leading to significant mainstem river flooding
may occur on the Pecos River in addition to flash flooding in
southeast New Mexico and west Texas.  No significant runoff is
expected over north central and northeast Texas for the forecast
period.

                     ...HYDROLOGIC DISCUSSION...
...Rio Grande Basin...
...Minor Flooding...
The largest concern in the Rio Grande basin continues to be potential
flows from the Rio Conchos out of northern Mexico into the Rio Grande
at Presidio.  Current forecasts are for minor flood levels at Presido
downstream of the International Bridge (PRST2) at the weir (PRDT2).
Flows in the Rio Conchos have been stable with little change since
Friday afternoon.  No significant rainfall is forecast in the Rio
Conchos basin for the next few days.  WGRFC will continue to monitor
the Rio Grande river conditions and adjust forecasts accordingly.

...San Jacinto Basin...
Heavy rains over portions of the San Jacinto brought tributaries to
slightly above bankfull levels yesterday but all are now subsiding
and have fallen below action criteria levels at this time.

...Pecos Basin...
...Bankfull and above...
The large flows in the tributaries above Brantley Reservoir continue
to recede.  Brantley reservoir has adequate storage available such
that it will not be making releases to contribute to existing
downstream flooding.  Downstream, the current level in Lake Avalon is
near conservation pool and continues to rise however no significant
spillway flows are expected. Downstream of Avalon to Red Bluff
reservoir, the Pecos River has fallen to below NWS action stage
criteria but not necessarily below bankfull.  Red Bluff reservoir
continues to rise. The current pool height was 2825.08 as of 15:15Z
9/20/2014 (assumed NGVD29).  The Red Bluff spillway elevation is
2826.7 NGVD29.  With no significant additional rainfall considered,
WGRFC does not expect Red Bluff reservoir to make a significant
downstream flow contribution to the existing overbank flow conditions
between Red Bluff reservoir and Pecos, Texas.  Stage/flow data for
that section of the Pecos River is limited.

...Remainder of WGRFC Basins...
Rainfall has continued across many parts of WGRFC with soil states
nearing saturation for most areas with exception of the northeast
Texas basins.  These wet areas of the WGRFC will likely again see
precipitation in some form of intensity today, but the current
forecast displays no rises beyond minor flooding at this time.


              ...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

CAZIER


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