000
WTPZ42 KNHC 121436
TCDEP2

Tropical Storm Jova Discussion Number   3
NWS National Hurricane Center Miami FL       EP122017
900 AM MDT Sat Aug 12 2017

First-light visible imagery from the experimental GOES-16 satellite
revealed that the circulation of Jova is very disorganized.  The
cyclone is strongly sheared from the northeast due to an upper-level
high centered over northwestern Mexico.  Since the convective
organization hasn't changed significantly since the last advisory,
the intensity has been held at 35 kt based on earlier ASCAT data.

There is no indication that the 20-25 kt of northeasterly shear
currently affecting the tropical storm will decrease enough to
allow for any intensification during the next day or so.  After
about 24 h, Jova will move into an environment of lower SSTs and
drier mid- to upper-level air, which should contribute to gradual
weakening.  The GFS, ECMWF, and HWRF models suggest that deep
convection will cease in about 48 h, so the forecast shows Jova
becoming a remnant low at that time.

The center was relocated to the north by about 30 n mi based on the
first-light visible imagery.  As a result, the NHC forecast track
has been shifted northward, especially for the first 48 h.  Aside
from the initial position uncertainty, there is fairly good
agreement among the models that a mid-level ridge extending from
northern Mexico across most of the tropical eastern North Pacific
will cause Jova to turn westward within the next 12-24 hours.  Jova
should then continue moving steadily westward along the southern
periphery of the ridge until eventual dissipation around or just
after 96 h.  The official forecast is basically an average of the
GFS and ECMWF models, which only differ in how quickly Jova
initially turns toward the west.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 20.1N 111.2W   35 KT  40 MPH
 12H  13/0000Z 20.3N 113.2W   35 KT  40 MPH
 24H  13/1200Z 20.5N 115.8W   35 KT  40 MPH
 36H  14/0000Z 20.6N 118.4W   30 KT  35 MPH
 48H  14/1200Z 20.7N 120.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  15/1200Z 20.7N 125.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  16/1200Z 20.0N 130.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  17/1200Z...DISSIPATED

$$
Forecaster Zelinsky