| Track: http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/?cone#contents "The flood threat is spreading farther east into Louisiana. Additional rainfall amounts of 15 to 25 inches are expected in southwestern Louisiana, with rainfall amounts of 5 to 15 inches expected in south-central Louisiana and 5 to 10 inches in southeastern Louisiana." Tropical Storm Harvey Discussion Number 34...Corrected NWS National Hurricane Center Miami FL AL092017 400 PM CDT Mon Aug 28 2017 Corrected initial intensity in first paragraph Radar and surface data show that the center of Harvey remains near or just off the Texas coast south of Matagorda. The associated convection has increased in intensity and coverage in a cluster extending from just north of the center northeastward into the Houston metropolitan area. Surface observations indicate that the central pressure is around 997 mb, and there are recent reports of sustained tropical-storm-force winds about 50-60 n mi southwest of the center. Based on these, the initial intensity is increased to 40 kt. Very heavy rains and life-threatening flash flooding continue over southeastern Texas and southwestern Louisiana. There have been reports of 2-day rainfall totals of close to 35 inches in the Greater Houston area. With the additional rains that are expected over the next several days, rainfall totals could reach 50 inches in some locations, which would be historic for the area. While Harvey continues to produce widespread heavy rain, the convective structure is not well organized in terms of being a tropical cyclone. In addition, a dry slot is seen in water vapor imagery over the southern and southeastern parts of the circulation, and the intensity guidance is not showing much additional development as Harvey crosses the northwestern Gulf of Mexico. The intensity forecast reflects these issues by showing little change in strength before landfall. Weakening and eventual decay into a remnant low are expected after landfall. The center has drifted erratically eastward since the last advisory, although a longer-term motion is 110/3. Harvey is currently between the subtropical ridge over the Gulf of Mexico and a large deep-layer ridge over the western United States, with a large trough in the westerlies weakening the Gulf ridge just enough to allow an east-southeastward motion. The large-scale models suggest that the westerlies should erode the western ridge to some extent during the forecast period, which should allow Harvey to turn north-northeastward under the greater influence of the Gulf ridge. The track guidance has changed little since the previous advisory except to show a faster motion from 96-120 h. The new forecast track remains close to that of the previous track, except for an increased forward speed by 120 h. Key Messages: 1. Ongoing catastrophic and life-threatening flooding will continue across southeastern Texas. Additional rainfall accumulations of 15 to 25 inches are expected across the upper Texas coast, with isolated storm totals as high as 50 inches. Please heed the advice of local officials. Do not attempt to travel if you are in a safe place, and do not drive into flooded roadways. Refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard. A summary of rainfall totals compiled by the Weather Prediction Center can be found at: www.wpc.ncep.noaa.gov/discussions/nfdscc1.html 2. The flood threat is spreading farther east into Louisiana. Additional rainfall amounts of 15 to 25 inches are expected in southwestern Louisiana, with rainfall amounts of 5 to 15 inches expected in south-central Louisiana and 5 to 10 inches in southeastern Louisiana. Please heed the advice of local officials and refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard in these areas. 3. While Tropical Storm Warnings have been extended eastward along the coast of Louisiana and a Storm Surge Watch has been issued, the impacts of winds and storm surge are expected to be secondary compared to that of the rains. FORECAST POSITIONS AND MAX WINDS INIT 28/2100Z 28.5N 95.7W 40 KT 45 MPH 12H 29/0600Z 28.4N 95.5W 40 KT 45 MPH 24H 29/1800Z 28.6N 95.0W 40 KT 45 MPH 36H 30/0600Z 29.2N 94.5W 40 KT 45 MPH 48H 30/1800Z 30.3N 94.1W 35 KT 40 MPH...INLAND 72H 31/1800Z 32.5N 93.0W 30 KT 35 MPH...INLAND 96H 01/1800Z 34.5N 91.5W 25 KT 30 MPH...INLAND 120H 02/1800Z 37.0N 89.0W 20 KT 25 MPH...POST-TROP/INLAND $$ Forecaster Beven Tropical Storm Harvey Advisory Number 34 NWS National Hurricane Center Miami FL AL092017 400 PM CDT Mon Aug 28 2017 ...SURFACE OBSERVATIONS SHOW THAT HARVEY HAS 45 MPH WINDS... ...LIFE-THREATENING FLOODING CONTINUES OVER SOUTHEASTERN TEXAS... ...DO NOT ATTEMPT TO TRAVEL IN THE AFFECTED AREAS IF YOU ARE IN A SAFE PLACE AND DO NOT DRIVE INTO FLOODED ROADWAYS... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...28.5N 95.7W ABOUT 45 MI...70 KM E OF PORT OCONNOR TEXAS ABOUT 145 MI...235 KM SW OF PORT ARTHUR TEXAS MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...ESE OR 110 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Tropical Storm Warning has been extended east of Cameron, Louisiana, to Intracoastal City, Louisiana. A Storm Surge Watch has been issued from Port Bolivar, Texas, to Morgan City, Louisiana. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Mesquite Bay to Intracoastal City A Storm Surge Watch is in effect for... * Port Bolivar to Morgan City Catastrophic and life-threatening flooding continues in southeastern Texas. Please see warnings and other products issued by your local National Weather Service office for additional information on this life-threatening situation. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. 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. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. Interests elsewhere along the middle and upper Texas coast and in southern Louisiana should continue to monitor the progress of Harvey. 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 center of Tropical Storm Harvey was located near latitude 28.5 North, longitude 95.7 West. Harvey is moving toward the east-southeast near 3 mph (6 km/h), and a slow motion toward the southeast is expected through tonight. A gradual turn toward the northeast and a continued slow forward speed are expected Tuesday and Tuesday night. On the forecast track, the center of Harvey is expected to be just offshore of the middle and upper coasts of Texas through Tuesday night, then move inland over the northwestern Gulf coast on Wednesday. Maximum sustained winds are near 45 mph (75 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours. Tropical-storm-force winds extend outward up to 175 miles (280 km) from the center. The National Ocean Service automated station at the Matagorda Bay entrance recently reported sustained winds of 46 mph (74 km/h) and a wind gust of 57 mph (92 km/h). The minimum central pressure estimated from surface observations along the Texas coast is 997 mb (29.44 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Harvey is expected to produce additional rainfall accumulations of 10 to 20 inches through Thursday over parts of the upper Texas coast into southwestern Louisiana. Isolated storm totals may reach 50 inches over the upper Texas coast, including the Houston/Galveston metropolitan area. These rains are currently producing catastrophic and life-threatening flooding over large portions of southeastern Texas. DO NOT ATTEMPT TO TRAVEL IN THE AFFECTED AREA IF YOU ARE IN A SAFE PLACE. DO NOT DRIVE INTO FLOODED ROADWAYS. Please see warnings and products issued by your local National Weather Service office for additional information on this life-threatening situation. Elsewhere, Harvey is expected to produce total rain accumulations of 5 to 15 inches farther south into the middle Texas coast and farther east across south-central Louisiana. Rainfall amounts of 5 to 10 inches are expected in southeast Louisiana. A list of rainfall observations compiled by the NOAA Weather Prediction Center can be found at: www.wpc.ncep.noaa.gov/discussions/nfdscc1.html 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... Port Aransas to Morgan City including Galveston Bay...1 to 3 ft The deepest water will occur along the immediate coast near the area of onshore winds. 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 rain bands well to the east of the center of Harvey, and along the coast to the southwest of the center. Tropical storm conditions are likely to persist within the warning area during the next couple of days. SURF: Swells generated by Harvey are affecting the coasts of Texas and Louisiana. 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 Tuesday across southern Louisiana and extreme southeast Texas. NEXT ADVISORY ------------- Next intermediate advisory at 700 PM CDT. Next complete advisory at 1000 PM CDT. $$ Forecaster Beven |