ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM

Tropical Storm John Discussion Number  18
NWS National Hurricane Center Miami FL       EP122018
800 PM PDT Thu Aug 09 2018

John continues to slowly weaken as the storm moves over 22 degrees C
waters well west of the Baja California Peninsula. Although cloud
tops have become progressively warmer over the past 12 hours,
satellite imagery indicates that the storm still has a well-defined
structure, with tight banding around the system center and an
eye-like feature. Based off the decrease in convection, the initial
intensity has been lowered to 50 kt. This is in agreement with an
average of Dvorak CI estimates from TAFB and SAB. Given the good
structure of the storm this evening, John will likely maintain
tropical storm intensity through most of Friday. After that time,
progressively cooler SSTs and stable air should cause convection
to dissipate sufficiently enough for John to be considered a remnant
low. Once it becomes a remnant low, the cyclone will gradually spin
down until it dissipates early next week.

After a leftward jog in the track earlier today, the tropical storm
has resumed a motion of 300/12 kt. This track is expected to
continue for the next couple of days with a gradual decrease in
forward speed. Thereafter, the left-biased GFS, which had been
calling for an interaction between the remnants of John and Tropical
Storm Kristy to the southwest, has now backed off that solution in
the 18Z run. This has resulted in a rightward shift in many of the
consensus models. With this shift in guidance, the forecast track
has also been adjusted slightly to the right, very close to the
latest TVCN solution, which has the remnant low of John drifting
northwest then north later this weekend into early next week.

Swells associated with John continue to affect portions of
the coast of the Baja California peninsula and are beginning to
reach portions of the southern California coast. These swells could
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 25.5N 119.6W   50 KT  60 MPH
 12H  10/1200Z 26.3N 121.0W   40 KT  45 MPH
 24H  11/0000Z 27.2N 122.7W   35 KT  40 MPH
 36H  11/1200Z 27.7N 124.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  12/0000Z 28.4N 124.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  13/0000Z 29.9N 125.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  14/0000Z...DISSIPATED

$$
Forecaster Cangialosi/Latto

NNNN