000
WTPZ43 KNHC 130852
TCDEP3

Tropical Storm Kiko Discussion Number   4
NWS National Hurricane Center Miami FL       EP132019
300 AM MDT Fri Sep 13 2019

Kiko's convective pattern has still not gotten any better
organized.  There's a small patch of convection near the estimated
center, with another larger cluster much farther south.  For the
most part, however, the circulation consists of a broken low- and
mid-level cloud deck with a few embedded showers.  Subjective Dvorak
estimates from TAFB and SAB are T2.0/30 kt, while objective numbers
are only slightly higher.  The initial intensity is being held at 35
kt, but it's entirely possible that Kiko may not be producing
tropical-storm-force winds at this time.

The GOES-17 air mass product shows that Kiko is surrounded by some
of the driest air over the entire tropical eastern Pacific, which
could be contributing to the system's convective struggles.  And
going forward, it appears that the thermodynamic environment could
be less than ideal for significant strengthening, with SHIPS model
diagnostics showing environmental stability to be the biggest
negative factor.  That being said, vertical shear is expected to be
less than 10 kt for at least the next 3 days, so strengthening is
likely if the dry air can be mixed out of the circulation.  The new
NHC forecast continues to show Kiko reaching hurricane strength in
about 48 hours, although the peak intensity has been tempered a bit
based on the latest guidance.  The official forecast is close to a
blend of the Florida State Superensemble and the HFIP Corrected
Consensus aids.

Kiko is moving west-northwestward, or 295/9 kt, to the south of a
mid-level ridge which extends along the U.S./Mexico border.  This
motion should continue for the next 3 days, and the track models
are in good agreement on this solution.  After day 3, there is
a bifurcation of the models, with the GFS, HMON, COAMPS-TC, and
Canadian turning Kiko northwestward or northward into a break in
the ridge, and the ECMWF, UKMET, HWRF, and the consensus aids
maintaining a west-northwestward or even westward heading on days 4
and 5.  Due to this divergence, the updated forecast shows a
slightly slower motion toward the end of the forecast period, but
the track itself is very similar to the previous forecast, lying
near the northern boundary of the southern camp of models.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0900Z 16.8N 113.5W   35 KT  40 MPH
 12H  13/1800Z 17.1N 114.9W   40 KT  45 MPH
 24H  14/0600Z 17.5N 116.6W   50 KT  60 MPH
 36H  14/1800Z 17.9N 118.3W   60 KT  70 MPH
 48H  15/0600Z 18.4N 120.0W   65 KT  75 MPH
 72H  16/0600Z 19.4N 123.1W   65 KT  75 MPH
 96H  17/0600Z 20.5N 125.5W   45 KT  50 MPH
120H  18/0600Z 21.0N 127.5W   35 KT  40 MPH

$$
Forecaster Berg