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Tropical Storm Hector Discussion Number 3
NWS National Hurricane Center Miami FL EP102018
200 AM PDT Wed Aug 01 2018
Hector is still somewhat disorganized, with a majority of its deep
convection displaced to the south and west of its surface center. In
fact, a recent AMSU pass around 0515 UTC indicated that the center
of Hector was nearly exposed on the northeast side of a small curved
band. Dvorak classifications from TAFB and SAB have not changed
since the last advisory and the ASCAT instruments missed the cyclone
once again, so the initial intensity has been held at 35 kt.
Easterly shear of around 10 kt, as analyzed in SHIPS diagnostics,
appears to be the primary factor preventing Hector from becoming
better organized. The latest GFS and ECMWF runs at 00Z suggest that
the shear will increase slightly during the next 24-36 hours before
decreasing substantially during the second half of the forecast
period. Despite the shear, all of the intensity guidance forecasts
that Hector will intensify in an otherwise favorable environment,
and the intensity guidance is generally higher than it was
previously. The dynamical hurricane models, HWRF, HMON, and
COAMPS-TC all bring Hector to near major hurricane strength, while
SHIPS and LGEM are a little lower. Given that Hector is still fairly
disorganized, the intensity forecast for the first 24 hours is
somewhat conservative, and favors the statistical-dynamical models.
Beyond that time, the NHC intensity forecast is a little higher than
it was previously, but is still just below the intensity consensus.
The estimated initial motion of the tropical storm is 285/13 kt.
Little change has been made to the track forecast, which has been
adjusted only slightly to the north through most of the forecast
period. The track guidance is in very good agreement on the track of
Hector, and the main source of uncertainty is the speed at which an
extensive mid-level ridge to the north will steer the cyclone
westward. Since I see no obvious reason to favor any one of the
typically-reliable global models, the NHC forecast is now very close
to the various consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 01/0900Z 13.4N 119.4W 35 KT 40 MPH
12H 01/1800Z 13.9N 121.1W 40 KT 45 MPH
24H 02/0600Z 14.2N 123.2W 50 KT 60 MPH
36H 02/1800Z 14.4N 125.2W 60 KT 70 MPH
48H 03/0600Z 14.4N 127.5W 65 KT 75 MPH
72H 04/0600Z 14.3N 132.0W 75 KT 85 MPH
96H 05/0600Z 14.0N 136.0W 80 KT 90 MPH
120H 06/0600Z 14.0N 140.0W 80 KT 90 MPH
$$
Forecaster Zelinsky
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