ZCZC MIATCPAT4 ALL TTAA00 KNHC DDHHMM BULLETIN Hurricane Harvey Advisory Number 20 NWS National Hurricane Center Miami FL AL092017 400 AM CDT Fri Aug 25 2017 ...HURRICANE HARVEY DANGEROUSLY APPROACHING THE TEXAS COAST... SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...25.9N 95.4W ABOUT 180 MI...290 KM SE OF CORPUS CHRISTI TEXAS ABOUT 185 MI...295 KM SSE OF PORT OCONNOR TEXAS MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H PRESENT MOVEMENT...NW OR 320 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...967 MB...28.56 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Port Mansfield to High Island Texas A Storm Surge Watch is in effect for... * South of Port Mansfield Texas to the Mouth of the Rio Grande A Hurricane Warning is in effect for... * Port Mansfield to Sargent Texas A Tropical Storm Warning is in effect for... * North of Sargent to High Island Texas * South of Port Mansfield Texas to the Mouth of the Rio Grande A Hurricane Watch is in effect for... * South of Port Mansfield Texas to the Mouth of the Rio Grande A Tropical Storm Watch is in effect for... * South of the Mouth of the Rio Grande to Boca de Catan Mexico A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, in this case within the next 12 to 24 hours. Preparations to protect life and property should be rushed to completion. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. A Hurricane Watch means that hurricane conditions are possible within the watch area. In addition, interests in southwestern Louisiana should continue to monitor the progress of this system. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside the United States, please monitor products issued by your national meteorological service. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 400 AM CDT (0900 UTC), the eye of Hurricane Harvey was located near latitude 25.9 North, longitude 95.4 West. Harvey is moving toward the northwest near 9 mph (15 km/h), and this general motion is expected to continue during the next couple of days. On the forecast track, Harvey will make landfall on the middle Texas coast tonight or early Saturday. Harvey is then likely to meander near or just inland of the middle Texas coast through the weekend. Maximum sustained winds are near 105 mph (165 km/h) with higher gusts. Some strengthening is possible, and Harvey is expected to become a major hurricane before it reaches the middle Texas coast. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km). The minimum central pressure reported by NOAA and Air Force planes was 967 mb (28.56 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Harvey is expected to produce total rain accumulations of 15 to 25 inches and isolated maximum amounts of 35 inches over the middle and upper Texas coast through next Wednesday. During the same time period Harvey is expected to produce total rain accumulations of 7 to 15 inches in far south Texas and the Texas Hill Country eastward through central and southwest Louisiana, with accumulations of up to 7 inches extending into other parts of Texas and the lower Mississippi Valley. Rainfall from Harvey will cause devastating and life-threatening flooding. STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water is expected to reach the following heights above ground if the peak surge occurs at the time of high tide... N Entrance Padre Island Natl Seashore to Sargent...6 to 12 ft Sargent to Jamaica Beach...5 to 8 ft Port Mansfield to N Entrance Padre Island Natl Seashore...5 to 7 ft Jamaica Beach to High Island...2 to 4 ft Mouth of the Rio Grande to Port Mansfield...2 to 4 ft High Island to Morgan City...1 to 3 ft The deepest water will occur along the immediate coast near and to the northeast of the landfall location, where the surge will be accompanied by large and destructive waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. WIND: Hurricane conditions are likely within the hurricane warning area late Friday and Friday night, with tropical storm conditions expected to first reach the coast in the hurricane warning area later this morning. These conditions are likely to persist into Saturday in portions of the hurricane and tropical storm warning area. SURF: Swells generated by Harvey will begin to affect the Texas, Louisiana, and northeast Mexico coasts later this morning. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. TORNADOES: Isolated tornadoes are possible across portions of the middle and upper Texas coast on Friday. NEXT ADVISORY ------------- Next intermediate advisory at 700 AM CDT. Next complete advisory at 1000 AM CDT. $$ Forecaster Avila NNNN