Tropical Storm Franklin Discussion Number   4
NWS National Hurricane Center Miami FL       AL072017
1000 AM CDT Mon Aug 07 2017

Visible and microwave satellite imagery shows that Franklin's cloud
pattern is becoming better organized with banding features starting
to appear. Inner-core convection is not very abundant over the
southwest quadrant and the center is still estimated to be located
near the southwest edge of the main cloud mass.  Given the increase
in organization after the 12Z Dvorak intensity estimate of 45 kt
from TAFB, the advisory intensity is set to 50 kt.  An Air Force
Hurricane Hunter aircraft is scheduled to investigate Franklin this
afternoon and should provide a better estimate of the strength of
the storm.  The upper-level environment is becoming increasingly
conducive for intensification, with anticyclonic outflow becoming
established over the tropical cyclone during the next couple of
days. Franklin could become a hurricane before its first landfall,
but interaction with the Yucatan Peninsula will cause some weakening
on Tuesday.  Thereafter, Franklin will be moving over SSTs near 30
deg C, which of course favors strengthening.  A complicating factor
at days 2 and 3 could be some northerly shear associated with an
upper-level ridge over northeastern Mexico, as indicated by the
global models.  Nonetheless Franklin should be near or at hurricane
intensity by the time it makes landfall in mainland Mexico.  The
official intensity forecast is a little above the model consensus.

The initial motion continues to be west-northwestward or 300/12 kt.
Little changes have been made to the track forecast from previous
advisories.  The steering environment remains fairly simple, and is
dominated by a zonally-oriented ridge that should cause a
west-northwestward to westward motion for the next several days.
The official track forecast is close to the dynamical model
consensus TVCN and leans slightly toward the ECMWF at the end of
the period.

FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 17.7N  85.1W   50 KT  60 MPH
12H  08/0000Z 18.5N  86.8W   60 KT  70 MPH
24H  08/1200Z 19.5N  88.9W   40 KT  45 MPH...INLAND
36H  09/0000Z 20.1N  91.1W   45 KT  50 MPH...OVER WATER
48H  09/1200Z 20.5N  93.3W   60 KT  70 MPH...OVER WATER
72H  10/1200Z 20.8N  97.8W   60 KT  70 MPH...INLAND
96H  11/1200Z...DISSIPATED

$$
Forecaster Pasch