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Hurricane Fernanda Discussion Number 32
NWS National Hurricane Center Miami FL EP062017
200 PM PDT Wed Jul 19 2017
Fernanda continues to slowly weaken, with the convection gradually
decreasing in coverage and intensity due to cool sea surface
temperatures and increasing shear. The initial intensity is
reduced to 70 kt based on a blend of the various satellite
intensity estimates, and this value is on good agreement with the
CIMSS satellite consensus.
The initial motion is now 300/7. Fernanda is expected to continue
this motion through 72 h as it is steered by a strong low- to
mid-level ridge to the north. This ridge is forecast to persist
after 72 h. However, the guidance continues to show divergence
during that time, with the models that forecast Fernanda to weaken
more quickly showing a more westward motion. One change in the
guidance since the last advisory is that the GFS and the HWRF show a
more westward motion after 72 h than previously, and this has helped
shift the consensus models southward to near the old forecast track.
Based on this, the new forecast track is changed little since the
previous advisory, and lies near the current runs of the consensus
models.
Fernanda is expected to steadily weaken through the forecast period
due to various combinations of cool sea surface temperatures,
southwesterly to southerly shear, and dry air entrainment. One
change from the previous advisory is to keep the system as a
tropical cyclone at 72 h based on the GFS and ECMWF forecasting
associated organized convection at that time. Otherwise, the new
intensity is similar to the previous forecast and in good agreement
with the intensity consensus.
The initial and forecast wind radii have been revised based on a
just-received scatterometer overpass.
FORECAST POSITIONS AND MAX WINDS
INIT 19/2100Z 17.7N 136.3W 70 KT 80 MPH
12H 20/0600Z 18.1N 137.3W 60 KT 70 MPH
24H 20/1800Z 18.7N 139.0W 50 KT 60 MPH
36H 21/0600Z 19.2N 140.6W 40 KT 45 MPH
48H 21/1800Z 19.7N 142.2W 35 KT 40 MPH
72H 22/1800Z 21.0N 145.5W 30 KT 35 MPH
96H 23/1800Z 22.0N 149.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 24/1800Z 23.0N 155.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Beven
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