Subtropical Storm Ernesto Discussion Number 2
Wiki-Hurricanes Forecast Center
5:00 PM AST Wed Aug 15 2018
Ernesto is beginning its lengthy transition to a tropical cyclone this afternoon. Satellite imagery indicates that convection is bubbly across the entirety of the its circulation, as opposed to being focused in one quadrant like last night. This should allow the storm-scale environment to moisten and become more supportive of convection. Exceptionally cold upper-air temperatures near -57C should provide ample instability for that convection to develop and allow Ernesto to become a warm core tomorrow. The initial intensity is held at 35kt in agreement with ST2.5/35kt from TAFB, but some intensification is expected over the next 24 hours as Ernesto remains over marginally warm ocean temperatures and in a low wind shear environment. Degeneration to a post-tropical cyclone is expected in about 36 hours before it merges with a frontal system around 3 days from now.
Ernesto is moving toward the north but should execute a turn toward the north-northeast in a few hours as a mid-level trough approaches from the west. It should continue on this path for the remainder of the forecast period before merging with the frontal system.
INIT 15/2100Z 35 KT 40 MPH...SUBTROPICAL STORM
12H 16/0600Z 40 KT 45 MPH
24H 16/1800Z 45 KT 50 MPH...TROPICAL STORM
36H 17/0600Z 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 17/1800Z 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 18/1800Z...MERGED WITH FRONTAL SYSTEM