500 AM HST WED AUG 31 2016 ...MADELINE WEAKENS AS IT DRAWS CLOSER TO HAWAII... ...STILL A CATEGORY ONE HURRICANE... SUMMARY OF 500 AM HST...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...18.9N 153.1W ABOUT 140 MI...230 KM ESE OF HILO HAWAII ABOUT 355 MI...565 KM ESE OF HONOLULU HAWAII MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H PRESENT MOVEMENT...W OR 260 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...988 MB...29.18 INCHES
At 500 AM HST (1500 UTC), the center of Hurricane Madeline was located near latitude 18.9 North, longitude 153.1 West. Madeline is moving toward the west near 14 mph (22 km/h) and this general motion is expected to continue for the next couple of days. On the forecast track, the center of Madeline will pass dangerously close to the Big Island later today. Maximum sustained winds are near 80 mph (130 km/h) with higher gusts. Steady weakening is forecast during the next 48 hours, and Madeline is forecast to weaken to a tropical storm tonight or Thursday. Hurricane-force winds extend outward up to 10 miles (20 km) from the center and tropical-storm-force winds extend outward up to 125 miles
Latest satellite imagery shows that Madeline is weakening in the presence of increasing shear, with conventional and microwave imagery no longer detecting an eye. Hurricane hunters with the 53rd Weather Reconnaissance Squadron spent a good portion of the evening flying through the cyclone, and found that it was weaker than anticipated, and tilted with height. The aircraft was also unable to find an eye, with maximum flight level winds near 80 kt. Satellite-based subjective Dvorak current intensity estimates were 5.0/90 kt, while data-T values ranged from 4.0/65 kt to 5.0/90 kt. The initial intensity for this advisory has been lowered to 80 kt, and this is likely generous based on the majority of the aircraft data.The initial motion estimate for this advisory is 260/10 kt. The steering flow is being provided by a building mid-level ridge to the north and northwest of the cyclone, which will impart a motion just south of due west over the next 24 to 36 hours. After this time, the ridge is expected to slide eastward, and a weakened Madeline is expected to move toward the west-northwest in the low- to mid-level trade wind flow. On the forecast track, the center of Madeline will pass dangerously close to the Big Island (Hawaii County) late Wednesday into Thursday, where a Hurricane Warning remains in place. The updated track forecast is very close to the previous as the bulk of the guidance suite continues to show run-to-run consistency, and lies close to the TVCN multi-model consensus. Madeline has rapidly weakened over the past 24 hours, and a steady weakening trend dominates the forecast, even as Madeline moves over warmer water. Vertical wind shear provided by a high-level trough to the north and northwest of the cyclone is expected to cause steady weakening as it imparts a debilitating northerly flow aloft and severely hampers outflow. While the updated intensity forecast is more aggressive in weakening Madeline than the previous forecast, it lies on the higher end of the intensity guidance. If current trends continue, then subsequent forecast packages may need to accelerate the weakening trend, especially given that the latest ECMWF guidance indicates dissipation by day 3 while the GFS and HWRF indicate degeneration to a remnant low on days 4 and 5. FORECAST POSITIONS AND MAX WINDS INIT 31/0900Z 19.2N 151.5W 80 KT 90 MPH 12H 31/1800Z 19.0N 153.0W 75 KT 85 MPH 24H 01/0600Z 18.7N 155.4W 70 KT 80 MPH 36H 01/1800Z 18.5N 157.4W 60 KT 70 MPH 48H 02/0600Z 18.6N 159.6W 55 KT 65 MPH 72H 03/0600Z 18.8N 165.2W 50 KT 60 MPH 96H 04/0600Z 19.2N 169.9W 45 KT 50 MPH 120H 05/0600Z 20.0N 174.0W 40 KT 45 MPH