Current Watches and Warnings A Hurricane Warning is in effect from Port Mansfield to Matagorda, Texas A Warning is in effect from north of Matagorda to High Island, Texas; south of Port Mansfield, Texas to the mouth of the Rio Grande A Hurricane Watch is in effect from south of Port Mansfield, Texas to the mouth of the Rio Grande A Watch is in effect from south of the mouth of the Rio Grande to Boca de Catan, Mexico A Surge Warning is in effect from Port Mansfield to San Luis Pass, Texas A Surge Watch is in effect from south of Port Mansfield, Texas to the mouth of the Rio Grande; north of San Luis Pass to High Island, Texas Current Details from the National Hurricane Center (NHC) COORDINATES: 24.0 north, 93.3 west LOCATION: 365 miles (590 kilometers) southeast of Corpus Christi, Texas MOVEMENT: north-northwest at 10 mph (17 kph) WINDS: 65 mph (100 kph) with gusts to 75 mph (120 mph) RADIUS OF TROPICAL STORM-FORCE WINDS: 90 miles (150 kilometers) MINIMUM CENTRAL PRESSURE: 982 millibars SAFFIR-SIMPSON SCALE RANKING*: 24-HOUR LANDFALL POTENTIAL: NONE 24-HOUR SIGNIFICANT INSURED LOSS POTENTIAL: LOW Latest Satellite Picture Source: NOAA Risk. Reinsurance. Human Resources.
Discussion Harvey, located approximately 365 miles (590 kilometers) southeast of Corpus Christi, Texas, is currently tracking north-northwest at 10 mph (17 kph). Data from an Air Force Hurricane Hunter aircraft indicates that Harvey is quickly strengthening, and the cyclone's structure has improved markedly with the plane now reporting a closed eye feature. The flight-level and surface-adjusted winds support the NHC setting an intensity of 65 mph (100 kph), but one of the more notable measurements is the central pressure, which has fallen to 982 millibars. With a pressure this low, it is likely that the winds will respond and increase further, and Harvey is likely not far from becoming a hurricane. With Harvey now strengthening at a faster rate than indicated in previous advisories, the NHC intensity forecast has become quite concerning. Water vapor images indicate that the cyclone's outflow is expanding, which suggests a low wind shear environment, and Harvey will be moving over a warm eddy of high oceanic heat content in the western Gulf of Mexico in about 24 hours. As a result of these conditions, several intensity models are now explicit in showing Harvey reaching major hurricane intensity. Even more concerning is that the SHIPS Rapid Intensification indices are incredibly high. As an example, the guidance is indicating a 70 percent chance of Harvey's winds increasing by 50 mph (85 kph) in the next 36 hours. Based on this guidance, the NHC official intensity forecast now calls for Harvey to reach major hurricane strength by 36 hours, before it reaches the middle Texas coast. Aircraft fixes indicate that Harvey has turned toward the north-northwest. A mid-level ridge of high pressure centered near Florida and the eastern Gulf of Mexico should force Harvey toward the northwest later today, with that trajectory continuing for the next couple of days. By 48 hours, the cyclone appears to get sandwiched between the same mid-level high over the Gulf of Mexico and a larger high over the Intermountain West. This is likely to cause Harvey to slow down considerably during its approach toward the Texas coast and then potentially stall just inland on days 3 through 5. Mainly based on an adjustment of the initial position, the NHC forecast track has been nudged northeastward on this cycle, but it still lies relatively close to the multi-model consensus. It is critical that users not focus on the exact forecast track of Harvey, since cycle-to-cycle adjustments are likely. All locations within the hurricane and storm surge warning areas should be preparing for the possibility of major hurricane-force winds and life-threatening storm surge. Cat Alert: Harvey 2
Key Messages from the National Hurricane Center 1. Harvey has intensified quickly this morning, and is now forecast to be a major hurricane at landfall, bringing life-threatening storm surge, rainfall, and wind hazards to portions of the Texas coast. Preparations to protect life and property should be completed by tonight, as tropical-storm-force winds will first arrive in the hurricane and storm surge warning areas on Friday. 2. A Surge Warning is in effect for much of the Texas coast. Life-threatening storm surge flooding could reach heights of 6 to 10 feet above ground level at the coast between the north entrance of the Padre Island National Seashore and Sargent. 3. Life-threatening flooding is expected across much of the Texas coast from heavy rainfall of 12 to 20 inches, with isolated amounts as high as 30 inches, from Friday through early next week. 4. The Potential Surge Flooding Map is available on the NHC website (and found below in this report). This product depicts a reasonable worst-case scenario the amount of inundation that has a 10 percent chance of being exceeded at each individual location. This map best represents the flooding potential in those locations within the watch and warning areas. Additional Information from the National Hurricane Center RAINFALL: Harvey is expected to produce total rain accumulations of 12 to 20 inches and isolated maximum amounts of 30 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 12 inches in far south Texas and the Texas Hill Country to central Louisiana, with accumulations of less than 5 inches extending into other parts of Texas and the lower Mississippi Valley. Rainfall from Harvey may cause 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: North Entrance Padre Island National Seashore to Sargent, Texas: 6 to 10 feet Sargent to San Luis Pass, Texas: 5 to 7 feet Port Mansfield to North Entrance Padre Island National Seashore, Texas: 5 to 7 feet San Luis Pass to High Island, Texas: 2 to 4 feet Mouth of the Rio Grande to Port Mansfield, Texas: 2 to 4 feet High Island, Texas to Morgan City, Louisiana: 1 to 3 feet 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. WIND: Hurricane conditions are likely within the Hurricane Warning area late Friday or Friday night, with tropical storm conditions expected to first reach the coast in the Hurricane Warning area Friday. SURF: Swells generated by Harvey are likely to affect the Texas, Louisiana, and northeast Mexico coasts by Friday. Cat Alert: Harvey 3
National Hurricane Center Forecast Cat Alert: Harvey 4
Most Likely Arrival Time of -Force Winds Cat Alert: Harvey 5
National Hurricane Center (NHC): Wind Speed Probabilities -Force Wind Probabilities ( 40 mph (65 kph)) Cat Alert: Harvey 6
Wind Probabilities ( 60 mph (95 kph)) Cat Alert: Harvey 7
Hurricane-Force Wind Probabilities ( 75 mph (120 kph)) Cat Alert: Harvey 8
NHC: Surge Inundation Graphic Cat Alert: Harvey 9
NHC: Surge Watch/Warning Graphic Cat Alert: Harvey 10
Weather Prediction Center: Rainfall Potential Cat Alert: Harvey 11
Current Spaghetti Model Output Data Source: NHC/ Atlantic Additional Information and Update Schedule Wind intensity forecasts and forecast track information can be found via the National Hurricane Center at www.nhc.noaa.gov NEXT CAT ALERT: Thursday afternoon after 4:00 PM CDT (21:00 UTC). Cat Alert: Harvey 12
* Intensity Classifications for Global Basins WIND SPEED KTS 1 MPH 1 KPH 1 30 35 55 NE Pacific, Atlantic National Hurricane Center (NHC) Depression NW Pacific Joint Typhoon Warning Center (JTWC) Depression BASINS AND MONITORING BUREAU NW Pacific Japan Meteorological Agency (JMA) Depression SW Pacific Fiji Meteorological Service (FMS) Depression Australia Bureau Of Meteorology (BOM) Low SW Indian Meteo-France (MF) Depression North Indian India Meteorological Department (IMD) Deep Depression 35 40 65 40 45 75 45 50 85 50 60 95 55 65 100 60 70 110 Cat. 1 Cat. 2 Cat. 1 Cat. 2 Moderate Cyclonic Cyclonic 65 75 120 70 80 130 75 85 140 80 90 150 Cat. 1 Hurricane Cat. 3 Cat. 3 85 100 160 90 105 170 95 110 175 100 115 185 105 120 195 110 125 205 Cat. 2 Hurricane Cat. 3 Major Hurricane Typhoon Typhoon Cat. 4 Cat. 4 Intense Very Cyclonic 115 130 210 120 140 220 125 145 230 130 150 240 135 155 250 Cat. 4 Major Hurricane 140 160 260 Cat. 5 Major >140 >160 >260 Hurricane Super Typhoon Cat. 5 Cat. 5 Very Intense Super Cyclonic Cat Alert: Harvey 13
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