Official Discussion issued by the National Hurricane Center

Franklin (AL072017) DATA RELEASED: 8/7/2017 3:00:00 AM UTC

Copy of official data

Tropical Storm Franklin Discussion Number   2
NWS National Hurricane Center Miami FL       AL072017
1100 PM EDT Sun Aug 06 2017

Last-light visible satellite pictures from GOES-13 and GOES-16
indicated that the low-level circulation of the disturbance had
become better defined and was located near the southwestern edge of
the main convective mass.  NOAA Buoy 42057, located about 90 n mi
northeast of the center, has reported peak 1-minute winds around 35
kt during the past few hours and a gust to 43 kt.  Because the
system has developed a closed circulation and well-defined center,
it is now classified as a tropical storm.  Franklin becomes the
sixth tropical storm of the 2017 Atlantic hurricane season.

The upper-level outflow is beginning to expand over the western
portion of the circulation, indicating that the shear over the
system is decreasing.  The global models are predicting that
Franklin will remain in a low-shear environment during the next
several days, and the only limiting factor for intensification
appears to be land interaction.  Additional strengthening is
expected before the cyclone reaches the Yucatan peninsula in about
24 hours.  After the system moves over the Bay of Campeche, warm
waters and favorable upper-level winds should allow for
restrengthening, and although not explicitly indicated in the
official forecast, Franklin could become a hurricane before it makes
final landfall in mainland Mexico.  The NHC forecast is closest to
the higher SHIPS guidance at 24 hours, and is near the intensity
consensus and HCCA models after that time.

The initial motion estimate is 295/11.  Franklin is forecast to
move west-northwestward during the next several days to the south
of a mid-level ridge that should remain in place over the northern
Gulf of Mexico.  The track model guidance has trended slightly
southward after 48 hours, and the new NHC track forecast has been
adjusted in that direction.  The NHC forecast remains near the
consensus of the GFS and ECMWF models.


FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 16.4N  83.0W   35 KT  40 MPH
12H  07/1200Z 17.4N  84.9W   40 KT  45 MPH
24H  08/0000Z 18.5N  87.1W   50 KT  60 MPH
36H  08/1200Z 19.5N  89.3W   35 KT  40 MPH...INLAND
48H  09/0000Z 20.2N  91.3W   40 KT  45 MPH...OVER WATER
72H  10/0000Z 20.9N  95.2W   60 KT  70 MPH
96H  11/0000Z 21.0N  99.5W   35 KT  40 MPH...INLAND
120H  12/0000Z...DISSIPATED

$$
Forecaster Brown