| Track: https://www.nhc.noaa.gov/refresh/graphics_at2+shtml/?cone#contents Tropical Storm Beta Discussion Number 6 NWS National Hurricane Center Miami FL AL222020 1000 PM CDT Fri Sep 18 2020 An Air Force Reserve Hurricane Hunter aircraft investigating Beta this evening found that the center has re-formed or been tugged northeastward by bursts of strong convection. While flying through that convection, the plane measured a peak flight-level wind of 57 kt at 10,000 feet before descending to 2500 feet. To the northwest of the center, the SFMR instrument on the plane measured a solid area of 46-48 kt, and there have been multiple ship reports in the region of 40-45 kt. Based on all these data, Beta's initial intensity is estimated to be 50 kt. The plane reported an extrapolated minimum pressure of 996 mb on the last pass through the center, which also corresponds to a typical 50-kt tropical storm. The aircraft fixes indicate that Beta is moving north-northeastward, or 030/10 kt. This motion is expected to continue for the next 12 hours or so, but as mid-level ridging develops over the Southern Plains on Saturday, Beta should begin to slow down and turn westward. A slow motion in the direction of the Texas coast should continue through day 3, with a shortwave trough possibly causing the cyclone to recurve and move northeastward near or along the Texas coast on days 4 and 5. While there remains a large amount of spread among the track models, they all agree on this general scenario and indicate that Beta is likely to move very slowly as it makes its closest approach to the Texas coast. The initial position fixed by the plane necessitated a northward shift in the NHC official forecast compared to the previous forecast for the first 3 days, but it comes back in line with the previous prediction on days 4 and 5. Beta has been able to strengthen despite being affected by strong southwesterly shear. The shear could begin to relax over the next few days, particularly by day 2 and 3, which could allow for some further strengthening. The SHIPS guidance remains the most aggressive of the intensity models, and the NHC intensity forecast leans heavily toward those solutions given Beta's recent intensification trend (which SHIPS seemed to handle better). Beta is forecast to steadily strengthen and become a hurricane in a couple of days as it approaches the Texas coast. Some weakening is forecast on days 4 and 5 due to another increase in southwesterly shear and possible land interaction. Key Messages: 1. There is an increasing risk of heavy rainfall and flooding along the northwest Gulf Coast Sunday through at least the middle of next week as Beta is forecast to move slowly toward and along or offshore of the coast through that time. For additional information, see products from your local National Weather Service office. 2. Life-threatening storm surge and hurricane-force winds are possible along portions of the Texas coast early next week, with tropical storm conditions possible by late this weekend. Storm Surge and Hurricane watches are in effect, and residents in these areas should ensure they have their hurricane plan in place and follow advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 25.5N 92.3W 50 KT 60 MPH 12H 19/1200Z 26.3N 92.2W 55 KT 65 MPH 24H 20/0000Z 26.8N 92.8W 60 KT 70 MPH 36H 20/1200Z 26.8N 93.7W 65 KT 75 MPH 48H 21/0000Z 27.0N 94.6W 70 KT 80 MPH 60H 21/1200Z 27.4N 95.5W 70 KT 80 MPH 72H 22/0000Z 27.8N 96.0W 70 KT 80 MPH 96H 23/0000Z 28.4N 95.8W 65 KT 75 MPH 120H 24/0000Z 29.4N 94.1W 55 KT 65 MPH $$ Forecaster Berg Tropical Storm Beta Advisory Number 6 NWS National Hurricane Center Miami FL AL222020 1000 PM CDT Fri Sep 18 2020 ...AIR FORCE RESERVE HURRICANE HUNTERS FIND BETA STRONGER... ...STORM SURGE AND HURRICANE WATCHES ISSUED FOR A PORTION OF THE TEXAS COAST... SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...25.5N 92.3W ABOUT 305 MI...495 KM E OF MOUTH OF THE RIO GRANDE ABOUT 315 MI...510 KM SW OF THE MOUTH OF THE MISSISSIPPI RIVER MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...NNE OR 30 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Storm Surge Watch has been issued from Port Mansfield, TX to High Island, TX including Baffin Bay, Corpus Christi Bay, Copano Bay, Aransas Bay, San Antonio Bay, Matagorda Bay, and Galveston Bay. A Hurricane Watch has been issued from Port Aransas, TX to High Island, TX. A Tropical Storm Watch has been issued from south of Port Aransas to the Mouth of the Rio Grande and east of High Island to Morgan City LA. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Watch is in effect for... * Port Mansfield, TX to High Island, TX including Baffin Bay, Corpus Christi Bay, Copano Bay, Aransas Bay, San Antonio Bay, Matagorda Bay, and Galveston Bay A Hurricane Watch is in effect for... * Port Aransas Texas to High Island Texas A Tropical Storm Watch is in effect for... * South of Port Aransas Texas to the Mouth of the Rio Grande * East of High Island Texas to Morgan City Louisiana 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. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. 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 OUTLOOK ---------------------- At 1000 PM CDT (0300 UTC), the center of Tropical Storm Beta was located near latitude 25.5 North, longitude 92.3 West. Beta is moving toward the north-northeast near 12 mph (19 km/h). A slow westward motion is expected to begin late Saturday, with a slow northwestward motion forecast to begin late Sunday and continue through late Monday. On the forecast track, the center of Beta will slowly approach the Texas coast into early next week. Data from the Air Force Hurricane Hunter aircraft indicate that maximum sustained winds have increased to near 60 mph (95 km/h) with higher gusts. Additional strengthening is forecast, and Beta is expected to become a hurricane on Sunday. Tropical-storm-force winds extend outward up to 175 miles (280 km) from the center. The estimated minimum central pressure is 996 mb (29.42 inches). HAZARDS AFFECTING LAND ---------------------- 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 could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Port Mansfield, TX to High Island, TX including Baffin Bay, Corpus Christi Bay, Copano Bay, Aransas Bay, San Antonio Bay, Matagorda Bay, and Galveston Bay...2-4 ft Mouth of the Rio Grande to Port Mansfield, TX...1-3 ft High Island, TX to Morgan City, LA including Sabine Lake, Calcasieu Lake, and Vermilion Bay...1-3 ft The deepest water will occur along the immediate coast in areas of onshore winds, 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 possible within the hurricane watch area by late Monday or Monday night, with tropical storm conditions possible by late Sunday. Tropical storm conditions are possible within the tropical storm watch area along the upper Texas and southwestern Louisiana coast as early as late Saturday. Tropical storm conditions are possible within the tropical storm watch area along the south Texas coast late Sunday. RAINFALL: There is an increasing risk of heavy rainfall and flooding along the northwest Gulf Coast Sunday through at least the middle of next week as Beta is forecast to move slowly toward and along or offshore of the coast through that time. For additional information, see products from your local National Weather Service office. SURF: Swells are expected to increase and reach the coast of Texas and the Gulf Coast of Mexico over the weekend, generated by a combination of Beta and a cold front entering the northern Gulf of Mexico. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 100 AM CDT. Next complete advisory at 400 AM CDT. $$ Forecaster Berg Satellite: https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL222020 https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al222020 NASA IR: https://weather.msfc.nasa.gov/cgi-bin/get-abi?satellite=GOESEastconusband13&lat=26&lon=-93&type=Animation&numframes=20&width=600&height=600&zoom=1&quality=55&map=standard&mapcolor=white&palette=ir2.pal |