Tropical Storm JULIO

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TROPICAL STORM JULIO DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102014
200 PM PDT TUE AUG 05 2014

Satellite imagery this afternoon indicates that Julio is becoming
better organized, with increased convective banding and cloud tops
colder than -80C near the center.  Satellite intensity estimates are
55 kt and 45 kt from TAFB and SAB respectively.  In addition, an
earlier CIMSS AMSU estimate was 53 kt.  Based on these data, the
initial intensity is increased to 55 kt.

The initial motion is now 280/12.  A low/mid-level ridge to the
north of the cyclone should steer it westward to west-northwestward
with some increase in forward speed during the next 3-4 days.
After that, the dynamical models forecast the ridge to weaken,
which would cause Julio to move more northward.  The track guidance
envelope is similar to the previous guidance through 72 hours, and
this part of the forecast is an update of the previous forecast.
From 72-120 hours, the guidance envelope has shifted significantly
to the north.  The new forecast track is also shifted northward,
but it still lies to the south of the consensus models and all of
the dynamical models except the GFDL/NAVGEM.  If the current model
trends continue, an additional northward adjustment may be
necessary in later advisories.  It should be noted that the NOAA
G-IV jet is currently flying a synoptic surveillance mission for
Hurricane Iselle, and the data from this mission will hopefully
help the subsequent forecasts for Julio.

Julio is now in a light vertical wind shear environment, and the
dynamical models suggest this will continue through the forecast
period.  However, the forecast track takes the system over
gradually decreasing sea surface temperatures during the next 48
hours.  The consensus of the intensity guidance is for continued
strengthening for the next 36-48 hours, and the increased banding
seen during the last few hours could be the start of a faster
intensification rate.  The new intensity forecast continues to call
for a peak intensity of 75 kt, and at this time only the
HFIP-sponsored University of Wisconsin model forecasts a higher peak
intensity.  After 48 hours, gradual weakening is expected as the
center moves along the 26C isotherm and this part of the new
forecast is in best agreement with the SHIPS model.


FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 14.2N 126.0W   55 KT  65 MPH
 12H  06/0600Z 14.7N 128.2W   60 KT  70 MPH
 24H  06/1800Z 15.4N 131.4W   65 KT  75 MPH
 36H  07/0600Z 16.0N 134.4W   75 KT  85 MPH
 48H  07/1800Z 16.6N 137.3W   75 KT  85 MPH
 72H  08/1800Z 17.5N 143.0W   70 KT  80 MPH
 96H  09/1800Z 19.0N 148.5W   60 KT  70 MPH
120H  10/1800Z 21.0N 153.0W   60 KT  70 MPH

$$
Forecaster Beven

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