Official Discussion issued by the National Hurricane Center

Kirk (AL122018) DATA RELEASED: 9/22/2018 5:00:00 PM UTC

Copy of official data

Tropical Storm Kirk Discussion Number   2
NWS National Hurricane Center Miami FL       AL122018
500 PM AST Sat Sep 22 2018

The convection associated with Kirk is currently disorganized, with
the majority of it in a cluster to the west of the center.  Most of
the subjective and objective satellite intensity estimates are in
the 30-35 kt range, so the initial intensity remains 35 kt for this

The forecast track takes Kirk over SSTs around 27C for the next 36
h or so with generally low shear, which appears favorable for
gradual strengthening.  However, there is a possibility that
entrainment of dry air from an area of African dust present to
the north of Kirk may allow less intensification than currently
forecast. From 36-72 h, there is some divergence in the intensity
guidance between the SHIPS and LGEM models, which forecast
strengthening into a hurricane, and the dynamical models, which
forecast little additional strengthening.  The intensity forecast
leans toward the dynamical models during that period.  After 72 h,
Kirk should encounter increasing westerly shear and gradually
weaken.  The intensity forecast, which is unchanged from the
previous forecast, lies a little above the intensity consensus IVCN.

The initial motion is now 290/13.  The subtropical ridge to the
north of the storm should steer Kirk quickly westward for the next
72 h or so, with forward speeds reaching 20-25 kt.  Later in the
forecast period, Kirk should turn west-northwestward with a
decrease in forward speed as it nears a developing weakness in the
ridge near and to the east of the Lesser Antilles.  The new
forecast track, which is closest to the HCCA consensus model, is
shifted a little to the north of the previous track.  However, it
continues to lie on the south side of the guidance envelope.


INIT  22/2100Z  8.6N  24.8W   35 KT  40 MPH
12H  23/0600Z  9.1N  27.1W   40 KT  45 MPH
24H  23/1800Z  9.5N  31.2W   45 KT  50 MPH
36H  24/0600Z  9.7N  35.7W   50 KT  60 MPH
48H  24/1800Z  9.8N  40.2W   50 KT  60 MPH
72H  25/1800Z 10.5N  48.0W   50 KT  60 MPH
96H  26/1800Z 11.5N  54.0W   45 KT  50 MPH
120H  27/1800Z 13.0N  59.0W   40 KT  45 MPH

Forecaster Beven