Hurricane John Discussion Number 13

Wiki-Hurricanes Forecast Center

2:00 PM PDT Wed Aug 8 2018

Hurricane John appears slightly more formidable this afternoon as it blows off some convective crust from the early morning diurnal rush, though the system remains generally ragged in appearance. As a result of some cloud shedding, a subsident area near the center of circulation has emerged in the past few hours and gives the apperance of an eye. However, the convective pattern around this eye feature does not really suggest too much in the way of strengthening has taken place. Microwave data from AMSU-B at 1700Z showed a partial eyewall open to the south. Long rainband tendrils remain present, particularly to John's southeast towards the direction of Socorro Island. SAB continued to estimate a T4.5/77kt intensity while TAFB remained lower at T4.0/65kt. John's structure is an enigma to automated intensity estimates, which have varied quite dramatically and thus are not considered for this advisory. With the overall organization remaining largely unchanged, the initial intensity remains at 70 kt.

John continues to track towards the northwest, and over time will gradually curve towards the west with the mid-level high-pressure area over the Western United States expands. John will be crossing a sharp sea surface temperature gradient later today with oceanic surface temperatures falling from near 28°C to near 24-23°C tonight. With lapse rates also decreasing, this should lead to a gradual decrease of convective activity out to dissipation. Intensity forecast values have been reevaluated based on new model data but the overall picture remains the same.


INIT 08/1200Z 70 KT 80 MPH

12H 09/0000Z 65 KT 75 MPH

24H 09/1200Z 55 KT 60 MPH

36H 10/0000Z 45 KT 50 MPH

48H 10/1200Z 35 KT 40 MPH

72H 11/1200Z 30 KT 35 MPH

96H 12/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW

120H 13/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW

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