073 
 WTPZ43 KNHC 270251
 TCDEP3
 
 TROPICAL STORM RACHEL DISCUSSION NUMBER  11
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182014
 800 PM PDT FRI SEP 26 2014
 
 Geostationary and microwave satellite imagery show a much improved
 structure for Rachel this evening.  A pronounced curved band has
 developed and wrapped around the center of the cyclone, while a
 mid-level eye is seen in 2002Z AMSR-E, 2130Z AMSU, and 0127Z SSMIS
 microwave passes.  Correspondingly, the Dvorak classifications from
 TAFB and SAB have jumped up to a 3.5.  This supports a 55 kt
 intensity, which may be conservative as the CIMSS AMSU method
 suggests maximum sustained winds of about 75 kt.  It appears likely
 that Rachel is responding to a reduction in the vertical shear, as
 it has now dropped below 10 kt.  Rachel has about 24 to 36 hr of
 conducive environmental conditions remaining before the atmosphere
 that it moves into becomes quite dry and stable. In about three
 days, the vertical shear increases which should hasten the demise of
 this system.  The NHC intensity prediction is based upon the IVCN
 multi-model ensemble through 48 hr and upon the HWRF and GFDL
 hurricane models after that time. The peak intensity indicated here
 is above that from the previous advisory due to the jump in the
 initial intensity.
 
 The aforementioned AMSU pass also provided some guidance from the
 CIRA size technique for the initial tropical-storm-force wind radii,
 which have been expanded outward some as a result.  The forecast
 wind radii, however, are anticipated to not grow much, based upon a
 blend of the dynamical and climatological models.
 
 Rachel's center apparently reformed southwestward closer to the
 deep convection earlier today, as suggested by a late arriving
 WindSat microwave pass.  While the uncertainty in the initial
 position is low, the current motion is a bit ambiguous due to the
 reformation.  It is estimated that the cyclone's center is moving
 toward the west-northwest at around 10 kt, primarily due to
 steering imparted by a mid-level subtropical ridge to its
 northeast.  A vigorous shortwave trough near California is
 anticipated to induce a break in the ridge and allow Rachel to turn
 toward the north-northwest at a slower rate of forward speed by
 Sunday.  In about three days, a decaying Rachel will start
 meandering in the weak low-level flow west of Baja California.  The
 NHC track forecast is based upon the TVCE multi-model ensemble,
 which shows substantial divergence in solutions late in the
 forecast period, and is slightly east of the track shown in the
 previous advisory.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  27/0300Z 18.4N 115.3W   55 KT  65 MPH
  12H  27/1200Z 19.1N 116.1W   60 KT  70 MPH
  24H  28/0000Z 20.0N 116.4W   65 KT  75 MPH
  36H  28/1200Z 20.9N 116.7W   65 KT  75 MPH
  48H  29/0000Z 21.5N 116.9W   55 KT  65 MPH
  72H  30/0000Z 22.1N 116.8W   40 KT  45 MPH
  96H  01/0000Z 22.0N 117.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 120H  02/0000Z 21.5N 117.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Landsea