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590 AGUS74 KFWR 271613 HMDFWR HYDROMETEOROLOGICAL DISCUSSION NATIONAL WEATHER SERVICE...WEST GULF RFC...FORT WORTH TX 1112 AM CDT SAT AUG 27 2016 VALID AUGUST 27 THROUGH SEPTEMBER 1 ...HEAVY RAINS EXPECTED ALONG THE TEXAS COAST THIS WEEKEND... ...METEOROLOGICAL DISCUSSION... Showers and thunderstorms will continue to impact the upper Texas and Louisiana coast this weekend, as an area of low pressure slowly moves across the Gulf of Mexico. Some scattered showers were noted on radar this morning over Southern Louisiana, however the main activity is offshore for now. One thing to note, there is a considerable amount of moisture flowing in from the Gulf of Mexico, and this should continue for the next few days. Therefore, the threat is high for very heavy rainfall, flash flooding and minor flooding to occur over the coastal areas this weekend. Rainfall amounts of 4-6 inches (isolated amounts up to 8 inches) are possible along the coastal areas of Texas and Louisiana, mainly today through Monday. Elsewhere, the activity over the Rio Grande has temporarily decreased, however precipitation chances are expected to increase through the weekend. Rainfall amounts of 1-2 inches are possible, which may result in higher than normal flows and/or minor flooding. By early next week, a ridge of high pressure will build back westward once again and deliver mostly dry conditions to most of Texas...excluding the Texas coast. Although a ridge of high pressure is forecast to dominate the area next week, there is still a lot of uncertainty on the development (if any) of an area of low pressure over the Gulf of Mexico and a Tropical Wave moving through the Caribbean Sea. We will continue to monitor the forecast models over the weekend and update accordingly. ...PRECIPITATION FORECAST... For Today into Sunday morning, Mean Areal Precipitation (MAP) amounts of up to 1.00 inch are forecast for portions of the upper Texas and Louisiana coasts. Lesser amounts are forecast for portions of southern new Mexico and West Texas. For Sunday into Monday morning, MAP amounts of up to 1.00 inch are forecast for portions of the upper Texas and Louisiana coasts. Lesser amounts are forecast for portions of southern new Mexico and West Texas. For Monday into Tuesday morning, MAP amounts of up to 1.00 inch are forecast for portions of the upper Texas and Louisiana coasts. Lesser amounts are forecast for portions of southern new Mexico and West Texas. For Tuesday into Thursday morning, MAP amounts of 0.25 to 0.50 inch are forecast for portions of the southeast Texas coast, Deep South Texas and New Mexico. After the widespread rain the past seven days over parts of New Mexico and Texas, drought conditions have eased somewhat. The U.S. Drought Monitor has categorized Texas as 29% abnormally dry, with less than 1% in severe drought. Over New Mexico, 88% of the state is abnormally dry, and 24% remains in the moderate drought category. The showers and thunderstorms forecast this week will keep more serious drought conditions from developing over the WGRFC region, while many sections continue drought-free. Since topsoil has become moister, some runoff is possible where the heaviest rain is forecast. However, as the weather dries out some this week most of the runoff will be insignificant across the majority of the WGRFC area. ...HYDROLOGIC DISCUSSION... ...Guadalupe Basin... ...Moderate Flooding... Lower end of the Guadalupe River continues to move flood waters to the Gulf. The last point along the river with a forecast is at Bloomington (DUPT2) which has crested but will remain above moderate flood stage for a few more hours and above flood stage for several more days. ...Rio Grande Basin... ...Higher Flow Non-Flood Forecasts... Heavy localized rains earlier this week have generated several waves of water causing a few locations to rise above criteria levels. The first wave from the Rio Conchos has arrived in Castalon which is cresting near flood stage today. Another wave from Terlingua creek has arrived at Boquillas Ranger station where the river has crested and is falling below criteria levels this morning. Reservoirs on the Mexican side of the river continue to slowly fill from all the recent rainfall activity. ...Nueces Basin... ...Higher Flow Non-Flood Forecasts... Runoff from rain that fell a few days ago continues to flow down the mainstem of the Nueces River and the Frio River. No flooding is expected at this time, but higher than normal flow will continue through the area over the next few days. Additional rises likely with precipitation returning to the region over the next few days. ...Remainder of WGRFC Basins... Soils are back to being fairly saturated over large areas of the WGRFC region. All other rivers are recovering from the last rain event and many locations are still well above normal flow for this tim eof year. With additional rainfall expected over the weekend, new rises are expected in many of our river systems during the next 5 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: 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: MCCANTS $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.