Hurricane JULIO

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HURRICANE JULIO DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102014
200 AM PDT WED AUG 06 2014

A small burst of deep convection with cloud tops of -75C to -80C has
developed over the low-level center, resulting in the formation of a
central dense overcast feature. In addition, passive microwave
satellite imagery has been indicating a 75-100 percent closed low-
to mid-level eye feature since about 0100 UTC. Satellite intensity
estimates are a consensus T4.0 from TAFB and SAB, so the initial
intensity has been increased to 65 kt, making Julio the fifth
hurricane of the 2014 eastern North Pacific season.

The initial motion estimate is 285/15 kt based on a blend of
conventional and microwave satellite fixes. The NHC model guidance
remains in excellent agreement on Julio moving along the southern
periphery of a deep-layer ridge to its north for the next 72 hours
or so. After that, a break in the ridge is forecast to develop north
of the Hawaiian Islands on Days 4 and 5, and Julio is expected to
turn more northwestward, passing just north of the Islands. However,
the new model runs, which have incorporated the 0000 UTC NOAA G-IV
jet dropsonde data are not showing as much erosion of the ridge as
in previous runs, and the response has been a slight southward shift
of the track guidance at 96 and 120 hours. The official forecast
track is just an update of the previous advisory track through 72
hours, and was shifted slightly southward after that, similar to the
consensus model TVCE, but not as far south as the ECMWF model. The
latter model brings Julio much closer to the Hawaiian Islands since
it no longer develops a break in the ridge.

The developing eye feature, low shear of less than 5 kt, and a
moistening mid-troposphere argue for at least some modest
strengthening for the next 36 hours or so as Julio moves from a SST
cold pool and over a warmer oceanic ridge. These condition also
typically favor rapid intensification, which would be a possibility,
except for the occasional intrusions of cooler and more stable air
from the north. However, it wouldn't be surprising if Julio
reaches its peak intensity a little sooner than forecast while the
upper-level outflow pattern continues to expand. By 48 hours, the
cyclone will be moving over cooler waters and into a more stable air
mass, which should induce gradual weakening. The official intensity
forecast is a little higher than the previous advisory and the
consensus model ICON.

FORECAST POSITIONS AND MAX WINDS

INIT  06/0900Z 14.8N 129.0W   65 KT  75 MPH
 12H  06/1800Z 15.4N 131.4W   70 KT  80 MPH
 24H  07/0600Z 16.1N 134.5W   75 KT  85 MPH
 36H  07/1800Z 16.7N 137.5W   80 KT  90 MPH
 48H  08/0600Z 17.3N 140.4W   75 KT  85 MPH
 72H  09/0600Z 18.5N 145.9W   65 KT  75 MPH
 96H  10/0600Z 20.4N 151.1W   55 KT  65 MPH
120H  11/0600Z 23.0N 156.0W   50 KT  60 MPH

$$
Forecaster Stewart

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