770 
 WTNT41 KNHC 040838
 TCDAT1
 
 Tropical Storm Florence Discussion Number  20
 NWS National Hurricane Center Miami FL       AL062018
 500 AM AST Tue Sep 04 2018
 
 Florence's cloud pattern has changed very little during the past
 several hours, with the exception of a possible small Central Dense
 Overcast developing just to the east of the center.  An earlier
 AMSR2 overpass revealed a rather obvious tilt toward the
 east-northeast, indicative of the moderate southwesterly shear.
 The initial intensity is held a 60 kt, and is supported by the
 Dvorak subjective and objective T-numbers.
 
 Florence should exhibit little change in strength during the next
 24 hours or so, as the cyclone traverses marginally warm sea surface
 temperatures and is influenced by modest west-southwesterly shear.
 Slight weakening is expected during the mid- forecast period as the
 shear gradually increases with time.  Afterward, the upper-level
 wind environment should become a little more favorable and, at the
 same time, Florence will be moving back over warmer SSTs.
 Consequently, the cyclone should gradually strengthen through day 5.
 This forecast is unchanged from the previous one, and is in good
 agreement with the NOAA-HCCA guidance.
 
 The initial motion estimate is west-northwestward, or 290/11 kt.
 The cyclone is expected to be steered west-northwestward for the
 next 48 hours by a mid- to upper tropospheric ridge anchored to
 the north, followed by a northwestward turn around the 72 hr period
 as it enters a growing weakness in the aforementioned ridge.  A
 rather large spread in the global and hurricane models remains
 particularly beyond day 4, however, the consensus models and the
 global ensemble means have have been fairly consistent from run to
 run.  This forecast is just a bit to the north of the previous
 advisory and just south of the consensus models.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  04/0900Z 19.3N  42.0W   60 KT  70 MPH
  12H  04/1800Z 19.9N  43.7W   60 KT  70 MPH
  24H  05/0600Z 20.8N  45.8W   60 KT  70 MPH
  36H  05/1800Z 21.8N  48.0W   55 KT  65 MPH
  48H  06/0600Z 22.9N  50.2W   50 KT  60 MPH
  72H  07/0600Z 25.2N  53.4W   50 KT  60 MPH
  96H  08/0600Z 27.1N  55.6W   55 KT  65 MPH
 120H  09/0600Z 29.1N  57.7W   65 KT  75 MPH
 
 $$
 Forecaster Roberts