Ana has been maintaining a persistent central dense overcast overnight and through the morning. Microwave data from 1435 and 1744 UTC showed that the active deep convection was displaced south of the LLCC which is indicative of shear impinging on the system. However...the latest visible and infrared images show an expanding and more symmetric outflow which suggests that the shear is easing and the system is becoming better organized. The latest subjective Dvorak intensity estimates came in at 55 kt from phfo and jtwc...and 65 kt from SAB. Based on a blend of these estimates...the initial intensity will be maintained at 60 kt. Considering the vigorous nature of the deep convection...Ana may be close to becoming a hurricane. The initial movement is 270/8kt with a deep layer ridge north of the cyclone providing the westward steering current. In the next 12 to 24 hrs...the orientation of the ridge will shift and produce a northwestward steering flow which is expected to bring Ana toward the main Hawaiian islands. The latest objective aids have become tightly clustered...even beyond 72 hours and the consensus track has remained largely unchanged. Thus...the current track is consistent with the previous forecast package except for a very small increase in speed. The track takes the center of Ana just south of The Big Island of Hawaii then northwest near Kauai and Oahu. The forward motion slows late Friday and into Saturday as the steering currents weaken due to the passage of a low pressure system north of the Hawaiian islands. The NOAA Gulfstream IV is scheduled to begin sampling the environment around Ana later today. The data from these flights should help improve subsequent model guidance. Despite the vertical shear currently affecting Ana...intensity guidance continues to show an intensification of Ana...though not quite as strong as earlier packages. HWRF and GFDL are the most aggressive while SHIPS indicates Ana will become a hurricane in 24 to 36 hours. With sufficiently warm SSTs and oceanic heat content...the forecast package leans toward the HWRF solution and calls for Ana to become a hurricane later today or tonight. A peak intensity forecast of 80 kt is expected early Friday. This is consistent with the previous package and is above the latest intensity consensus. SHIPS calls for increasing vertical shear to start weakening Ana late Friday or Saturday. Interests in the main Hawaiian islands should continue to monitor the future progress of Ana. A Hurricane Watch may be required for portions of the island chain later today or tonight. Forecast positions and Max winds init 15/2100z 14.3n 147.4w 60 kt 70 mph 12h 16/0600z 14.6n 148.7w 65 kt 75 mph 24h 16/1800z 15.1n 150.4w 70 kt 80 mph 36h 17/0600z 15.9n 152.1w 75 kt 85 mph 48h 17/1800z 17.0n 153.7w 80 kt 90 mph 72h 18/1800z 19.4n 156.4w 75 kt 85 mph 96h 19/1800z 21.0n 158.0w 65 kt 75 mph 120h 20/1800z 22.5n 159.5w 60 kt 70 mph $$ forecaster kodama icons.wunderground/data/images/cp201402_5day.gif
Posted on: Thu, 16 Oct 2014 02:27:49 +0000
Trending Topics
Recently Viewed Topics
© 2015