Tropical Cyclone Discussion
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WTNT41 KNHC 040843

500 AM AST SUN OCT 04 2015

The cloud pattern of Joaquin has continued to gradually deteriorate
overnight with most of the deep convection now located over the
eastern and southeastern portions of the circulation.  The earlier
reconnaissance aircraft mission reported peak 700-mb flight-level
winds of 125 kt, and SFMR surface winds of 94 kt during its last
pass through the southeastern portion of eyewall just before 0500
UTC.  Dropsonde and SFMR data suggest that the flight-level winds
are not mixing down as efficiently as before, and the initial
intensity is lowered to 105 kt, which is a blend of the various
reconnaissance wind data.  Another Air Force Reserve Hurricane
Hunter aircraft is currently en route to the storm and should
provide a better assessment of Joaquin`s intensity this morning.

Recent center fixes indicate that the motion of Joaquin has started
to bend toward the north-northeast, but the longer term motion is
still northeastward or 040/17 kt.  The hurricane should turn
north-northeastward this morning, and pass near Bermuda this
afternoon as it moves between a large mid- to upper-level low to
its west and a mid-level ridge over the central Atlantic.  After
passing the Bermuda Joaquin is expected to turn northeastward, then
east-northeastward after 48 hours when it reaches the mid-latitude
westerlies.  The updated NHC track is similar to the previous
advisory and it remains near the center of the tightly cluster
guidance models.

Moderate to strong southwesterly shear is expected to cause some
weakening during the next 12 to 24 hours, but Joaquin is forecast to
remain a strong hurricane while it passes near or over Bermuda later
today.  Gradual weakening should continue after 24 hours, as the
hurricane encounters cooler waters and remains within an environment
of moderate shear.  Joaquin is expected to become an extratropical
cyclone over the North Atlantic in a little more than 72 hours.
The official intensity forecast is close to the model consensus
through 72 hours, and is based on guidance from the Ocean Prediction
Center at 96 and 120 h when the cyclone will be post-tropical.


INIT  04/0900Z 29.7N  67.7W  105 KT 120 MPH
 12H  04/1800Z 31.6N  66.4W   90 KT 105 MPH
 24H  05/0600Z 33.7N  65.5W   85 KT 100 MPH
 36H  05/1800Z 35.5N  64.1W   80 KT  90 MPH
 48H  06/0600Z 37.6N  61.0W   75 KT  85 MPH
 72H  07/0600Z 41.8N  49.0W   65 KT  75 MPH
 96H  08/0600Z 45.0N  33.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  09/0600Z 50.0N  21.0W   55 KT  65 MPH...POST-TROP/EXTRATROP

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