762 
 WTPZ45 KNHC 301432
 TCDEP5
 
 Hurricane Rosa Discussion Number  22
 NWS National Hurricane Center Miami FL       EP202018
 800 AM PDT Sun Sep 30 2018
 
 Rosa continues to be affected by increasing southwesterly shear and
 cooler waters.  Most of the deep convection has been eroded over
 the southern semicircle of the circulation.  The current intensity
 estimate is reduced to 65  kt in agreement with ADT estimates from
 UW/CIMSS.  An Air Force Reserve Unit Hurricane Hunter aircraft will
 investigate Rosa later today to provide a better estimate of the
 intensity of the system.  Since the vertical shear is predicted to
 continue to increase and SSTs should cool to below 23 deg C by
 Monday, additional weakening is likely before Rosa reaches the
 Baja California peninsula.  The official intensity forecast is near
 the high end of the numerical guidance.
 
 The hurricane is moving just east of north, or around 010/11 kt.
 The track forecast reasoning is unchanged from the previous
 advisory package.  Rosa is likely to be steered north-northeastward
 in the flow ahead of a large mid-level trough approaching from the
 west.  This should take the center of the cyclone across Baja
 California in the Tropical Storm Warning area by Monday night.
 Rosa or it's remnant should move over the Desert Southwest on
 Tuesday.  The official track forecast is similar to the previous
 one and roughly in the middle of the dynamical guidance.
 
 Key Messages:
 
 1. The main hazard expected from Rosa or its remnants is very heavy
 rainfall in Baja California, northwestern Sonora, and the U.S.
 Desert Southwest.  These rains are expected to produce
 life-threatening flash flooding and debris flows in the deserts, and
 landslides in mountainous terrain.  For more information about
 potential rainfall in that area, please see products from the
 Weather Prediction Center and your local NWS forecast office.
 
 2. Tropical storm conditions are expected over portions of the
 central and northern Baja California peninsula on Monday, possibly
 spreading to the northern Gulf of California Monday night.
 Interests in those locations should monitor the progress of Rosa.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  30/1500Z 24.4N 118.6W   65 KT  75 MPH
  12H  01/0000Z 25.9N 117.9W   60 KT  70 MPH
  24H  01/1200Z 27.5N 116.7W   55 KT  65 MPH
  36H  02/0000Z 29.3N 115.4W   45 KT  50 MPH
  48H  02/1200Z 31.8N 114.0W   30 KT  35 MPH...INLAND
  72H  03/1200Z 36.5N 111.5W   20 KT  25 MPH...POST-TROP/INLAND
  96H  04/1200Z...DISSIPATED
 
 $$
 Forecaster Pasch