| Track: http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/?cone Hurricane Harvey Advisory Number 22 NWS National Hurricane Center Miami FL AL092017 400 PM CDT Fri Aug 25 2017 ...MAJOR HURRICANE HARVEY BEARING DOWN ON THE TEXAS COAST... ...CATASTROPHIC FLOODING EXPECTED DUE TO HEAVY RAINFALL AND STORM SURGE... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...27.5N 96.5W ABOUT 60 MI...95 KM ESE OF CORPUS CHRISTI TEXAS ABOUT 60 MI...100 KM S OF PORT OCONNOR TEXAS MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H PRESENT MOVEMENT...NW OR 325 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Tropical Storm Warning has been discontinued south of Port Mansfield, Texas. The Storm Surge Watch has been discontinued south of Port Mansfield, Texas. The government of Mexico has discontinued the Tropical Storm Watch north of Boca de Catan. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Port Mansfield to High Island Texas 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 A Storm Surge Warning means there is a danger of life-threatening inundation from rising water moving inland from the coastline 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. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, in this case within the next few hours. Preparations to protect life and property should already be complete. Interests in southwestern Louisiana should continue to monitor the progress of this system. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 400 PM CDT (2100 UTC), the eye of Hurricane Harvey was located by aircraft reconnaissance aircraft and NOAA Doppler radar near latitude 27.5 North, longitude 96.5 West. Harvey is moving toward the northwest near 10 mph (17 km/h), but its forward speed is expected to decrease significantly 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. Data from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds have increased to near 125 mph (205 km/h) with higher gusts. Harvey is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some additional strengthening is possible before Harvey makes landfall overnight. Weakening is then expected over the weekend while the center moves inland over Texas. Hurricane-force winds extend outward up to 35 miles (55 km) from the center, and tropical-storm-force winds extend outward up to 140 miles (220 km). A station at Aransas Pass, Texas, recently reported a sustained wind 56 mph and a gust to 71 mph. The minimum central pressure based on aircraft reconnaissance data is 941 mb (27.79 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Harvey is expected to produce total rain accumulations of 15 to 30 inches and isolated maximum amounts of 40 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 5 to 15 inches in far south Texas and the Texas Hill Country over through southwest and central Louisiana. Rainfall of this magnitude will cause catastrophic 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...3 to 5 ft Jamaica Beach to High Island...2 to 4 ft Mouth of the Rio Grande to Port Mansfield...1 to 3 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: Tropical storm conditions are occurring in portions of the hurricane and tropical storm warning areas, and hurricane conditions are expected to begin within the hurricane warning area in the next few hours. Tropical storm conditions are likely to persist along portions of the coast through at least Sunday. SURF: Swells generated by Harvey are affecting the Texas, Louisiana, and northeast Mexico coasts. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. TORNADOES: A few tornadoes are possible through Saturday near the middle and upper Texas coast into far southwestern Louisiana. NEXT ADVISORY ------------- Next intermediate advisory at 700 PM CDT. Next complete advisory at 1000 PM CDT. $$ Forecaster Berg Hurricane Harvey Discussion Number 22 NWS National Hurricane Center Miami FL AL092017 400 PM CDT Fri Aug 25 2017 Despite its concentric eyewall structure, Harvey's winds have increased during the day. NOAA and Air Force Reserve Hurricane Hunter planes have measured maximum flight-level winds of 129 kt and SFMR winds to 102 kt. Based on these data, Harvey's maximum surface winds are estimated to be 110 kt. Harvey's central pressure has also continued to fall, and the latest estimate based on dropsonde data is 941 mb. Harvey still has not slowed down, and the initial estimate is 325/9 kt. Based on the forecast track, Harvey is expected to make landfall along the middle Texas coast tonight. After that, the track models insist that the hurricane will slow down considerably during the next 24 hours, and it is likely to move very little between 36 and 120 hours. In fact, there has been a somewhat notable change in the guidance, with very few of the models showing Harvey lifting out toward the northeast by the end of the 5-day forecast period. As a result, the NHC track forecast has been pulled back a bit and keeps Harvey near or just inland of the Texas coast through the middle of next week. This slow motion only exacerbates the heavy rainfall and flooding threat across southern and southeastern Texas. Harvey may continue to strengthen during the 6-12 hours it has before landfall, but regardless it is expected to make landfall at major hurricane strength. Gradual weakening is anticipated after the center moves inland, but Harvey's slow motion will keep a significant portion of its circulation over water, which may slow the weakening rate. As a result, the NHC intensity forecast leans closer to the global model guidance instead of the statistical- dynamical guidance, which seems to weaken Harvey too fast. Harvey could maintain tropical storm strength for the entire 5-day forecast period due to its proximity to the northwestern Gulf of Mexico. Key Messages: 1. Harvey will make landfall tonight, bringing life-threatening storm surge, rainfall, and wind hazards to portions of the Texas coast. Tropical-storm-force winds have moved onshore in portions of the warning areas and conditions will continue to deteriorate as the eye of Harvey approaches the middle Texas coast tonight. 2. A Storm Surge Warning is in effect for much of the Texas coast. Life-threatening storm surge flooding could reach heights of 6 to 12 feet above ground level at the coast between the north entrance of the Padre Island National Seashore and Sargent. For a depiction of areas at risk, see the Storm Surge Watch/Warning Graphic at hurricanes.gov. Due to the slow motion of Harvey and a prolonged period of onshore flow, water levels will remain elevated for several days. 3. Catastrophic and life-threatening flooding is expected across the middle and upper Texas coast from heavy rainfall of 15 to 30 inches, with isolated amounts as high as 40 inches, through Wednesday. Please refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 27.5N 96.5W 110 KT 125 MPH 12H 26/0600Z 28.2N 97.0W 100 KT 115 MPH...INLAND 24H 26/1800Z 28.8N 97.5W 75 KT 85 MPH...INLAND 36H 27/0600Z 28.9N 97.8W 60 KT 70 MPH...INLAND 48H 27/1800Z 28.6N 97.8W 50 KT 60 MPH...INLAND 72H 28/1800Z 28.1N 96.9W 40 KT 45 MPH...INLAND 96H 29/1800Z 28.5N 96.0W 40 KT 45 MPH...OVER WATER 120H 30/1800Z 29.5N 95.5W 35 KT 40 MPH...INLAND $$ Forecaster Berg |