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HURRICANE ANDRES DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015
200 AM PDT SAT MAY 30 2015
Andres is producing a relatively compact area of strong convection,
but the high-level cirrus canopy continues to obscure an eye in
infrared satellite imagery. A 0501 UTC AMSU pass showed that the
bulk of the deep convection is located within the eastern and
southern eyewall--probably the result of 15-20 kt of north-
northwesterly shear. Nonetheless, Dvorak estimates have notched
upward just a bit (T5.0/90 kt from TAFB, T4.5/77 kt from SAB, and
T4.5/77 kt from the UW-CIMSS ADT), and the initial intensity is
therefore set at 80 kt.
The hurricane is currently located due south of a weakness in the
subtropical ridge, resulting in a northwestward motion of 325/6 kt.
Mid-level ridging is expected to strengthen to the north and
northwest of Andres during the next couple of days, which should
induce a west-northwestward turn by tonight. The track guidance is
in good agreement during the first 48 hours but then diverges
thereafter. The GFS appears to keep Andres as a hurricane for too
long after it reaches colder water, and its solution is therefore
considered to be a northern outlier. Otherwise, the remainder of
the guidance is in relatively good agreement, and the official track
forecast is nearly on top of the previous one.
Global model fields and SHIPS guidance suggest that the shear
affecting Andres will continue for another 18-24 hours. However,
the shear doesn't appear quite strong enough to significantly
disrupt the circulation, and the thermodynamic environment remains
conducive for some further short-term strengthening. After 24
hours, the oceanic heat content falls to zero, so Andres will begin
to upwell colder water and start a steady weakening trend that will
continue through the end of the forecast period. The intensity
guidance is in general agreement of this scenario, and the new NHC
intensity forecast is just an update of the 0300Z forecast, close
to the multi-model consensus (ICON).
FORECAST POSITIONS AND MAX WINDS
INIT 30/0900Z 14.0N 115.6W 80 KT 90 MPH
12H 30/1800Z 14.7N 116.4W 85 KT 100 MPH
24H 31/0600Z 15.4N 117.6W 80 KT 90 MPH
36H 31/1800Z 16.0N 118.8W 75 KT 85 MPH
48H 01/0600Z 16.5N 120.0W 70 KT 80 MPH
72H 02/0600Z 17.8N 122.9W 60 KT 70 MPH
96H 03/0600Z 19.0N 126.5W 50 KT 60 MPH
120H 04/0600Z 19.0N 129.5W 35 KT 40 MPH
$$
Forecaster Berg
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