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HURRICANE HERNAN DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014
200 PM PDT SUN JUL 27 2014
A faint eye was briefly apparent on visible satellite images, and
Dvorak classifications from TAFB as well as objective Dvorak
intensity estimates from UW-CIMSS support an intensity of 65 kt.
Therefore, Hernan is being upgraded to the third hurricane of the
2014 eastern North Pacific season. The system has a quite
impressive and symmetrical upper-level outflow pattern at this time.
Sea surface temperatures will be decreasing along the path of the
tropical cyclone, and vertical shear is expected to gradually
increase. Therefore, a weakening trend should commence on Monday.
The official intensity forecast closely follows the latest model
The initial motion remains northwestward, or 305/13. There is no
significant change to the track forecast or the reasoning behind
it. For the next few days, Hernan will continue to be steered by
the flow on the southwest side of a ridge associated with a
mid-tropospheric high centered over the southwestern United States.
This ridge is forecast to build westward somewhat, which should
cause the track of Hernan to gradually shift toward the
west-northwest. By the latter part of the forecast period, the
weakening and increasingly shallow cyclone is likely to turn
westward following the lower-tropospheric steering flow. The
official track forecast is very close to the track model consensus,
TVCN, and is basically an update of the previous NHC forecast.
Based on a recent ASCAT overpass, only slight adjustments to the
wind radii were required.
FORECAST POSITIONS AND MAX WINDS
INIT 27/2100Z 18.6N 112.2W 65 KT 75 MPH
12H 28/0600Z 19.7N 113.9W 65 KT 75 MPH
24H 28/1800Z 21.2N 116.3W 60 KT 70 MPH
36H 29/0600Z 22.6N 118.7W 50 KT 60 MPH
48H 29/1800Z 23.4N 120.6W 45 KT 50 MPH
72H 30/1800Z 24.2N 124.0W 30 KT 35 MPH
96H 31/1800Z 24.5N 127.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 01/1800Z 24.5N 129.5W 20 KT 25 MPH...POST-TROP/REMNT LOW