478 
 WTPZ42 KNHC 062032
 TCDEP2
 
 Tropical Storm Aletta Discussion Number   4
 NWS National Hurricane Center Miami FL       EP022018
 300 PM MDT Wed Jun 06 2018
 
 Aletta's cloud pattern has not become noticeably better organized
 during the day, and the banding features are not very well
 defined in enhanced infrared imagery.  There is a dry intrusion
 over the northwest quadrant of the circulation with some
 restriction of the upper-level outflow over that quadrant as well.
 Dvorak classifications from both TAFB and SAB give a current
 intensity of 35 kt but a recent scatterometer pass indicated that
 the maximum winds are close to 40 kt, and that value will be used
 for the advisory intensity.  Although the storm has not
 strengthened since early this morning, it is anticipated that the
 cyclone will be moving through fairly low vertical shear and over
 SSTs of 28 or 29 deg C during the next few days.  This favorable
 environment should cause intensification.   The official forecast,
 which is close to the simple or corrected model consensus guidance,
 continues to call for Aletta to become a hurricane by late Thursday
 or early Friday.
 
 High temporal and spatial resolution GOES-16 imagery suggested
 multiple low-level swirls near the estimated center position.
 Based on geostationary and microwave imagery along with the
 scatterometer data, the initial motion continues to be slowly
 westward or 270/7 kt.  The flow on the south side of a mid-level
 ridge extending from Mexico into the eastern North Pacific should
 continue to steer Aletta westward to west-northwestward over the
 next few days.  In 3-4 days, most of the track guidance shows the
 cyclone bending a little more to the right in response to a
 weakness in the ridge.  As was the case in the previous cycle, the
 GFS shows the northernmost track and the ECMWF the southernmost.
 The official forecast lies between these extremes and is close to
 the model consensus.  This is a tad slower than the previous NHC
 forecast.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  06/2100Z 14.2N 107.9W   40 KT  45 MPH
  12H  07/0600Z 14.4N 109.0W   50 KT  60 MPH
  24H  07/1800Z 14.5N 110.0W   55 KT  65 MPH
  36H  08/0600Z 14.7N 111.0W   65 KT  75 MPH
  48H  08/1800Z 15.0N 112.0W   70 KT  80 MPH
  72H  09/1800Z 16.0N 113.6W   80 KT  90 MPH
  96H  10/1800Z 17.3N 115.6W   70 KT  80 MPH
 120H  11/1800Z 18.0N 117.0W   45 KT  50 MPH
 
 $$
 Forecaster Pasch