Tropical Storm ANDRES Advisory Fri May 29

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HURRICANE ANDRES DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP012015
300 PM MDT FRI MAY 29 2015

Convective banding features have increased since the previous
advisory, and a tight banding eye feature has occasionally appeared
in visible satellite imagery. Dvorak satellite estimates
are a consensus T4.0/65 kt from TAFB and SAB, and UW-CIMSS
ADT values are T4.3/72 kt. Based on these data, Andres has been
upgraded to a 65-kt hurricane.

Andres has made the anticipated turn toward the northwest, and the
initial motion estimate is now 310/06 kt. This general motion is
expected to continue for about the next 36-48 hours as the
hurricane moves around the western periphery of a deep-layer ridge
located across mainland Mexico and Baja California. The ridge is
forecast to gradually build westward during Days 3-5, forcing
Andres to turn back toward the west-northwest. The NHC model is in
excellent agreement on this developing scenario, and the guidance is
tightly clustered around the previous forecast track. As a result,
the official forecast track is just an update and extension of the
previous advisory track.

Despite moderate northerly vertical wind shear, Andres has
maintained a fairly impressive outflow pattern. However, the 850-200
mb vertical wind shear is forecast by the SHIPS model to increase to
around 16 kt during the next 24 hours, followed by decreasing shear
at 36 to 48 hours. Now that Andres has established better inner-core
convection and a possible eye feature, at least modest strengthening
should occur during the next 48 hours or so. Thereafter, decreasing
sea surface temperatures and cooler and more stable low-level air
lying just to the northwest of the hurricane should begin to affect
Andres. Visible satellite imagery already indicates that cold
air stratocumulus clouds are being advected into the northwestern
portion of the outer circulation, which should mitigate the
otherwise favorable thermodynamic conditions. As a result, a steady
decrease in the intensity should occur on Days 3-5, despite the low
vertical wind shear regime through which the cyclone will be moving.
The NHC intensity forecast is similar to the previous advisory, and
is above the intensity consensus model ICON and close to the SHIPS
model.

FORECAST POSITIONS AND MAX WINDS

INIT  29/2100Z 12.8N 114.8W   65 KT  75 MPH
 12H  30/0600Z 13.6N 115.6W   70 KT  80 MPH
 24H  30/1800Z 14.7N 116.6W   75 KT  85 MPH
 36H  31/0600Z 15.7N 117.7W   80 KT  90 MPH
 48H  31/1800Z 16.4N 119.1W   80 KT  90 MPH
 72H  01/1800Z 17.4N 121.9W   65 KT  75 MPH
 96H  02/1800Z 18.5N 125.4W   50 KT  60 MPH
120H  03/1800Z 18.8N 128.7W   40 KT  45 MPH

$$
Forecaster Stewart