Hydrometeorological Discussion
Issued by NWS West Gulf RFC

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AGUS74 KFWR 201617
HMDFWR
HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX
1016 AM CST THU NOV 20 2014

                VALID NOVEMBER 20 THROUGH NOVEMBER 25

...SIGNIFICANT RAINFALL IS EXPECTED FOR THE EASTERN HALF OF TEXAS
THIS WEEKEND...

                   ...METEOROLOGICAL DISCUSSION...
Confidence continues to increase for a widespread (beneficial)
precipitation event this weekend.  Low level southerly winds are
transporting gulf moisture northward, with surface dewpoints in the
low to mid 60s along the coast, low 50s to just south of the DFW
Metroplex.  Higher dewpoints are a good indication of low level
moisture, but the mid and upper levels of the atmosphere remain dry
as precipitable water (PW) values are running 50% to 75% of normal.
This should change over the next 48 hours.

An active southern branch of the jet stream will bring a strong
Pacific system onshore today, and will dive southeast across the
Desert Southwest through early Saturday.  The upper level flow will
become more favorable for the transport of deeper mid level moisture,
which will help set the stage for showers and thunderstorms.  With
abundant moisture and significant large scale lift (courtesy of the
previously mentioned Pacific system), widespread showers and
thunderstorms should form later Friday, becoming more organized
Saturday.  Severe weather is also expected Saturday.

At this time, rainfall amounts could exceed 2 to 3 inches in some
areas.  Locally heavy rainfall could produce areas of runoff.  Due to
the localized nature, widespread river flooding is not expected.

Later this weekend, after the strong Pacific storm system has exited
the area, drier weather will return for the start of next week.

                    ...PRECIPITATION FORECAST...
For Today into Friday morning, Mean Areal Precipitation (MAP)
amounts of 0.25 inch or less are forecast for the Texas Coast and
East Texas.

For Friday into Saturday morning, MAP amounts of pf 0.50 to 1 inch
are forecast for the Red River Basin and for portions of the Big
Country.  MAP amounts of 0.25 inch or less are forecast for the
remainder of Texas.

For Saturday into Sunday morning, MAP amounts of 1 to 1.50 inches are
forecast for a large portion of Texas, generally east of a line from
Wichita Falls to Austin to Corpus Christi.  MAP amounts of 0.25 to
0.50 inch are forecast for the area east of a line from Childress to
San Angelo to Brownsville.  Lighter MAP amounts are expected across
the remainder of Texas.

For Sunday into Tuesday morning, MAP amounts of 0.25 to 0.50 inch are
forecast for Southern Colorado.  Lighter MAP amounts are forecast for
Northern New Mexico.

Moderate or worse drought conditions continue to be observed over
parts of New Mexico and Texas.  In Texas, about half the state is
experiencing moderate or worse drought (44%) and 10% has extreme to
exceptional drought. In New Mexico, nearly two thirds of the state is
experiencing moderate or worse drought (63%) and 2% has extreme to
exceptional drought. Significant rainfall is expected this weekend
and should be heavy enough to produce runoff in some areas, mainly
over the eastern 2/3 of Texas.  Mainstem river flooding is not
expected.

                     ...HYDROLOGIC DISCUSSION...
...WGRFC Basins...
Rivers will remain below flood criteria the next couple of days.
However, significant precipitation is forecast across portions of North
and East Texas this weekend. As a result, some higher than normal flows
and/or minor flooding is possible across the upper Trinity and Sabine
River systems the next five days.

              ...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

WALLER


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