Tropical Storm John Discussion Number 15
Wiki-Hurricanes Forecast Center
3:00 AM MDT Thu Aug 9 2018
John continues to weaken this morning, with a bundle of moderate convection over the center of its sprawling low-level circulation. A 0514z ASCAT pass indicated a sole 50kt wind barb to the north of the center. Given the low bias of the instrument, the initial intensity has been decreased to 55kt, directly in line with the latest estimate from UW-CIMSS ADT. Continued weakening is expected over colder water and in dry air, and John should degenerate to a remnant low within 48 hours. Dissipation is expected around day 5.
The track forecast remains pretty easy. John is moving northwest on the southwestern edge of a mid-level ridge. This motion should continue for the next 2 to 3 days. Thereafter, as John becomes a shallow area of low pressure, it should turn west under the influence of low-level flow before stalling out at the end of the period in a light steering regime.
MAXIMUM WINDS FORECAST
INIT 09/0900Z 55 KT 65 MPH
12H 09/1800Z 50 KT 60 MPH
24H 10/0600Z 45 KT 50 MPH
36H 10/1800Z 40 KT 45 MPH
48H 11/0600Z 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 12/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 13/0600Z 15 KT 20 MPH...POST-TROP/REMNT LOW