483 
 WTPZ44 KNHC 060837
 TCDEP4
 
 TROPICAL STORM SIMON DISCUSSION NUMBER  19
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP192014
 200 AM PDT MON OCT 06 2014
 
 Simon's cloud pattern continues to deteroriate.  Microwave data
 indicate that the cyclone's low-level center is exposed to the
 southwest of the main convective mass due to strong southwesterly
 vertical wind shear.  The remaining central convection is no longer
 very deep either, with cloud top temperatures having risen to -50
 to -60 deg C.  A large plume of stratiform rain and high clouds
 also extends well north and east of the center, though even this
 area has been shrinking.  The initial wind speed is reduced to 50 kt
 based on a blend of Final T-numbers of 3.0/45 kt and 3.5/55 kt from
 TAFB and SAB, respectively, which should provide a reasonable
 estimate of the intensity in cases of rapid weakening.
 
 Extremely strong westerly vertical shear of 30-40 kt will cause a
 decoupling of the cyclone during the next day or two, while very
 unfavorable thermodynamic conditions should result in a loss of
 deep convection.  This should cause the rapid weakening trend
 observed during the past 24 hours to continue, and remnant low
 status is now predicted in 36 hours or perhaps sooner.  The remnant
 circulation could dissipate prior to reaching the Baja California
 peninsula, as indicated by the latest SHIPS model output, or in the
 very least arrive in a greatly weakened state.  The NHC wind speed
 forecast is largely an update of the previous one in agreement with
 the latest multi-model consensus.
 
 Simon has turned northward, or 360/06, around the western periphery
 of a subtropical ridge extending westward near the southwestern
 coast of Mexico.  A shortwave trough moving toward southern
 California should turn the cyclone north-northeastward in the next
 12 to 24 hours, but Simon will have just begun to recurve when it
 shears apart.  The track guidance shows the remnant circulation
 continuing north-northeastward at varying forward speeds, with the
 GFS still much faster than the ECMWF and UKMET.  The NHC track
 forecast is very near the previous one and the multi-model consensus
 through 48 hours but is slower after that time to acknowledge the
 possibility that a weaker system than depicted in global model
 fields might not reach the northern Baja California peninsula.
 
 Even if Simon or its remnant circulation does not make it across the
 rugged terrain of the Baja California peninsula, moisture associated
 with this system is expected to spread across the northern Baja
 California peninsula, northwestern Mexico, and into the U.S. Desert
 Southwest, which could trigger heavy rains in those regions during
 the next few days.
 
 
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  06/0900Z 24.4N 117.6W   50 KT  60 MPH
  12H  06/1800Z 25.3N 117.5W   40 KT  45 MPH
  24H  07/0600Z 26.4N 117.0W   30 KT  35 MPH
  36H  07/1800Z 27.6N 116.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
  48H  08/0600Z 28.8N 115.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
  72H  09/0600Z 30.2N 114.2W   15 KT  15 MPH...POST-TROP/REMNT LOW
  96H  10/0600Z...DISSIPATED
 
 $$
 Forecaster Kimberlain