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621 AGUS74 KFWR 231644 HMDFWR HYDROMETEOROLOGICAL DISCUSSION NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX 1144 AM CDT THU APR 23 2015 VALID APRIL 23 THROUGH APRIL 28 ...THE PARADE OF STORM SYSTEMS WILL CONTINUE OVER MUCH OF THE WGRFC AREA THE NEXT FIVE DAYS... ...METEOROLOGICAL DISCUSSION... An upper air disturbance moved eastward from Mexico across south Texas the past 24 hours. This disturbance interacted with a northward moving warm front to bring some showers and thunderstorms to south Texas. Rainfall amounts were locally heavy in this region the past 24 hours, with amounts in the 2.00 to 3.00 inch range. Over the northern parts of the WGRFC area, atmospheric moisture increased ahead of a developing low pressure system to our southwest. Showers and thunderstorms developed ahead of the dry line over northwest Texas, and these storms moved eastward across north Texas overnight. Also, showers and thunderstorms developed across central Texas where an outflow boundary had set up (which had moved southward from Oklahoma earlier Wednesday). Locally heavy rain also fell over this part of Texas, with the area around Waco receiving 2.75 to 3.50 inches. This rain has temporarily diminished this morning. This morning a low pressure system was located over southern California. Our region continues to be under a southwesterly upper air flow which will keep our weather unsettled through late Friday. Ahead of this low, showers and thunderstorms are forecast to develop east of the dry line. At this point the area which appears to be most favorable for locally heavy rainfall is over southwest Texas around Eagle Pass and Bracketville as an upper air disturbance approaches. Some of these thunderstorms should move northeast across central and perhaps north Texas tonight. Then on Friday the California low will finally begin to move eastward. As this occurs there will likely be a few periods of showers and thunderstorms over a good part of Texas and Louisiana. Locally heavy rains may occur over portions of northeast Texas and northern Louisiana with the stronger thunderstorms. By Friday night the low pressure system will move over Kansas, with dry air moving into Texas from the west. This will cause the rainfall to diminish late Friday night and Saturday over most of the area except for Texas Gulf coastal region. A weak ridge of high pressure will bring dry weather for most of the region for Saturday into Sunday morning. By Sunday a new low pressure system is forecast to develop and move toward the four corners region. This will bring mixed precipitation over northern New Mexico and southern Colorado Sunday and Monday. And over Texas there will be another chance for showers and thunderstorms later Sunday, but will be more likely over east Texas and Louisiana on Monday. By Monday night a closed low pressure system is forecast to be over Oklahoma. Some wrap-around rainfall is possible across northern Texas late Monday into Tuesday. ...PRECIPITATION FORECAST... For Today into Friday morning, Mean Areal Precipitation (MAP) amounts of 0.25 inch or more are forecast from southwest into central and north Texas. The heaviest rain, with MAP amounts of 1.00 inch, are forecast over south Texas near Eagle Pass. Lighter amounts of MAP are forecast for much of the WGRFC region...except for far west Texas and the southeast half of New Mexico. For Friday into Saturday morning, MAP amounts of 0.25 inch or more are forecast for roughly the southeastern half of Texas into most of Louisiana. The heaviest rain, with MAP amounts of 2.00 inches, are forecast over extreme northeast Texas and northern Louisiana. Lighter amounts of MAP are forecast for much of the WGRFC region...except for west Texas and the southern two thirds of New Mexico. For Saturday into Sunday morning, MAP amounts of 0.25 inch or more are forecast for extreme southeast Texas along and near the middle and upper Texas Gulf coast into southern Louisiana. MAP amounts of 0.25 of an inch are also forecast across southwestern Colorado. Lighter amounts of MAP are forecast for the southeast third of Texas, most of Louisiana, most of Colorado, and the northwest third of New Mexico. For Sunday into Tuesday morning, MAP amounts of 0.25 inch or more are forecast for the northeast half of Texas, Louisiana, northeast New Mexico, and over most of Colorado. The heaviest rain, with MAP amounts of 2.00 inches, are forecast over central Louisiana just east of Toledo Bend Lake. Lighter amounts of MAP are forecast for much of the WGRFC region...except for southwest Texas and southern 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 9% has extreme to exceptional drought conditions. In New Mexico, a little over half of the state is experiencing moderate or worse drought (58%). 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, 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 runoff over east central and northeast Texas where the heaviest rainfall is forecast. No significant runoff is expected over the remainder of the WGRFC area. ...HYDROLOGIC DISCUSSION... ...San Bernard Basin... ...Moderate Flooding... The initial Flood Wave has crested at all sites along the San Bernard and in recession. The San Bernard near Boling (BOLT2) is still at moderate flood levels and slowly receding. Downstream near Sweeny (SWYT2) the river is slightly above minor flood stage but slowly receding. ...Guadalupe Basin... ...Moderate Flooding... The Guadalupe River at Victoria is still in recession and should be below bankfull this evening. At Du Pont Plant near Bloomington (DUPT2) the river will remain above moderate flood levels for another day or so then begin to recede. ...Neches Basin... ...Minor Flooding... Most of the Neches River Basin is extremely saturated due to recent rainfall. Lake Palestine is also 1.5 ft above normal. As a result, minor flooding is occurring at several locations across the entire basin. These conditions are expected to continue for the next several days. River level recessions will be slow at most of these locations. ...Sabine Basin... ...Minor Flooding... Cowleech Fork Sabine River at Greenville (GNVT2) is experiencing a rapid rise due to heavy rains but is expected to crest this afternoon and fall. The South Fork Sabine River near Quinlan (QLAT) is also expected to crest around minor flood stage this evening or tomorrow morning. The Sabine River at Mineola (MLAT2) has crested and is in slow recession. Further downstream, Deweyville near Ruliff (DWYT2) on the Sabine has crested but will remain at minor flood levels for a few more days then fall below criteria. ...San Antonio Basin... ...Higher Flow Non-Flood Forecasts... heavy rainfall from a thunderstorm over the lower portions of the basin caused Cibolo creek near Falls City (FCTT2) to experience a flashy rise above action stage but has now fallen below this criteria. On the mainstem at Goliad (GLIT2) locally heavy rains will push the site into action stage today with a crest near 17 feet. ...Brazos Basin... ...Higher Flow Non-Flood Forecasts... The Navasota River near Normangee (NGET2) is currently at higher than normal flow levels. The river at this location is currently falling but is expected to remain above criteria levels for the next several days. The remainder of the entire Brazos River system are below criteria levels. ...Trinity Basin... ...Higher Flow Non-Flood Forecasts... heavy rains yesterday have caused a rapid rise on the East Fork Trinity River at McKinney (MCKT2). It is expected to crest slightly below minor flood levels this morning then fall rapidly. The Trinity River at Moss Bluff (MBFT2) is expected to have a flat crest fluctuating around action stage with little change through the forecast period. ...Nueces Basin... The Nueces River near Tilden (TILT2) has crested and will continue to fall slowly over the next few days. ...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 rivers which already are experiencing 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 $$