219 
 WTPZ45 KNHC 011432
 TCDEP5
 
 Tropical Storm Rosa Discussion Number  26
 NWS National Hurricane Center Miami FL       EP202018
 800 AM PDT Mon Oct 01 2018
 
 Most of Rosa's deep convection has been sheared northeastward
 over portions of the Baja California peninsula, Sonora, and the
 southwestern United States.  Locally heavy rains are already
 occurring over those areas.  Assuming a gradual weakening of the
 cyclone since the last scatterometer overpass, and blending Dvorak
 intensity estimates from TAFB and SAB, gives a current intensity
 estimate of 40 kt.  Since the cyclone will continue to be influenced
 by strong shear, cooler waters, and then interact with land,
 continued weakening is likely over the next day or so.  Rosa is
 expected to degenerate into a remnant low by the time it reaches the
 southwestern United States on Tuesday.
 
 The system is moving north-northeastward, or 030/10 kt.  Rosa
 should continue to be steered on that heading, to the east of a
 broad mid-level trough off the California coast.  Some increase in
 forward speed is expected after Rosa's remnants move into the
 Desert Southwest.  The official track forecast remains very close to
 the multi-model consensus.
 
 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 affecting portions of the
 central and northern Baja California peninsula,  especially over
 higher elevations.  These conditions could spread into the northern
 Gulf of California later tonight. Interests in those locations
 should monitor the progress of Rosa.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  01/1500Z 27.5N 116.5W   40 KT  45 MPH
  12H  02/0000Z 28.9N 115.6W   35 KT  40 MPH
  24H  02/1200Z 31.3N 114.3W   30 KT  35 MPH
  36H  03/0000Z 34.3N 112.9W   20 KT  25 MPH...POST-TROP/INLAND
  48H  03/1200Z 37.0N 112.0W   15 KT  15 MPH...POST-TROP/INLAND
  72H  04/1200Z...DISSIPATED
 
 $$
 Forecaster Pasch
 
 

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