000
WTNT42 KNHC 070245
TCDAT2

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

Buenas tardes. En las últimas imágenes por satélite, en la visible, diría que se está formando ya el ojo...

000
WTNT42 KNHC 080241
TCDAT2

Tropical Storm Franklin Discussion Number   6
NWS National Hurricane Center Miami FL       AL072017
1000 PM CDT Mon Aug 07 2017

Satellite images and radar data from Belize show that Franklin has
an expansive and nearly symmetric circulation.  However, recent
microwave data indicate that the cyclone does not have a
well-defined inner core, which is characterized by an elliptical
ring of convection that is open on the northwest side.  In addition,
cloud tops are not very cold near the center, and the deepest
convection is located in a band well to the east of the center over
the Caribbean Sea.  Earlier Hurricane Hunter aircraft data indicated
that maximum winds were near 50 kt, and since the satellite
presentation has not improved since then, that will remain
Franklin's initial intensity.

Franklin appears to have turned west-northwestward and sped up just
a bit with an initial motion of 300/12 kt.  A mid-tropospheric
ridge extending across the northern and central Gulf of Mexico
should force Franklin west-northwestward and westward across
the Yucatan peninsula and into the Bay of Campeche during the next
day or two, which is handled well by the numerical models.  After
36 hours, there is some latitudinal spread in the track guidance,
likely related to how Franklin's circulation interacts with the
mountainous terrain of Mexico.  Since tropical cyclones in the
western Bay of Campeche historically have tended to turn a little
southward prior to landfall, the updated NHC track forecast is a
little south of the previous forecast, leaning in the direction of
the HFIP Corrected Consensus and the GFS.

Given Franklin's structure and limited time before landfall, the
cyclone is unlikely to strengthen before the center reaches land.
Weakening is anticipated while Franklin takes about 18 hours to
cross the Yucatan peninsula, but the storm should then begin to
restrengthen once it reaches the warm waters of the Bay of Campeche
tomorrow evening.  It does appear that northerly shear may begin to
increase in about 36 hours, but it does not look strong enough to
prevent intensification.  Continuing the pattern of following the
HFIP Corrected Consensus and the ICON intensity consensus, the
official forecast shows Franklin reaching hurricane intensity in
about 48 hours, and then making landfall on the coast of mainland
Mexico as a hurricane between 48 and 72 hours.  Despite what is
explicitly indicated in the forecast, Franklin's low-level center
is likely to dissipate near the mountains of Mexico, with the
mid-level remnants continuing westward across central Mexico.

Based on the updated forecast, the government of Mexico has
discontinued the Hurricane Watch for the east coast of the Yucatan
peninsula but has issued a new Hurricane Watch for parts of the
state of Veracruz in mainland Mexico.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 19.1N  87.3W   50 KT  60 MPH
 12H  08/1200Z 19.7N  88.9W   40 KT  45 MPH...INLAND
 24H  09/0000Z 20.2N  91.1W   45 KT  50 MPH...OVER WATER
 36H  09/1200Z 20.5N  93.1W   55 KT  65 MPH
 48H  10/0000Z 20.6N  95.2W   65 KT  75 MPH
 72H  11/0000Z 20.0N 100.4W   30 KT  35 MPH...INLAND
 96H  12/0000Z...DISSIPATED

$$
Forecaster Berg