000
WTPZ41 KNHC 140837
TCDEP1

TROPICAL STORM KARINA DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP112014
200 AM PDT THU AUG 14 2014

Deep convection associated with Karina has been expanding during
the last several hours, and microwave images suggest that the
storm is maintaining a tight inner core.  Dvorak intensity
estimates from TAFB and SAB were both 3.0/45 kt at 0600 UTC, but
recent ADT values from UW-CIMSS are a little higher.  The initial
wind speed is nudged upward to 50 kt based on the latest trends.

East-northeasterly shear of 10 to 15 kt is currently affecting
Karina, which is restricting the outflow on the east side of the
circulation.  Although the shear is not expected to change much
during the next 24 to 36 hours, it should lessen beyond that time
period.  The official intensity forecast continues to call for
steady strengthening during the next few days while Karina remains
over warm water and in a relatively moist air mass.  Gradual
weakening is predicted in 4 to 5 days when the system moves
over more marginal sea surface temperatures.  This forecast is
similar to the previous one, and remains at the upper end of the
model guidance.

Karina is moving westward at about 12 kt on the southwest side of a
deep layer ridge centered over northern Mexico and the southwestern
United States.  This ridge is expected to build westward over the
Pacific Ocean, which should keep the storm moving westward at about
the same forward speed for the next few days.  After that time, the
track forecast is complicated by the potential interaction with
other low pressure areas moving out of the Intertropical Convergence
Zone.  The GFS shows a more northerly track of Karina due its
interaction with a disturbance to the west of the storm, while the
ECMWF shows a more southerly track due to its interaction with the
developing system to the east of Karina. The NHC track forecast is
between these scenarios, close to the model consensus, and is just a
tad to the north of the previous advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  14/0900Z 17.4N 115.2W   50 KT  60 MPH
 12H  14/1800Z 17.5N 116.9W   60 KT  70 MPH
 24H  15/0600Z 17.7N 119.1W   65 KT  75 MPH
 36H  15/1800Z 18.0N 121.5W   70 KT  80 MPH
 48H  16/0600Z 18.2N 123.8W   75 KT  85 MPH
 72H  17/0600Z 18.6N 128.1W   75 KT  85 MPH
 96H  18/0600Z 18.2N 131.3W   70 KT  80 MPH
120H  19/0600Z 18.0N 133.5W   60 KT  70 MPH

$$
Forecaster Cangialosi