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Tropical Storm Andres Discussion Number   4
NWS National Hurricane Center Miami FL       EP012021
900 PM MDT Sun May 09 2021
 
Andres remains a ragged-looking tropical cyclone this evening. The
majority of the deep convection is displaced well to the east of
the low-level center and there is little evidence of banding
features.  Dvorak intensity estimates from both SAB and TAFB still
support an intensity of 35 kt, and that value is used as the initial
wind speed for this advisory, although that may be generous given
the recent satellite presentation.  Overnight scatterometer data
should provide a better assessment of the cyclone's intensity.
 
Increasing southwesterly vertical wind shear and dry mid-level air
should cause Andres to begin to weaken overnight or on Monday, if
that weakening trend has not already begun. Andres is forecast to
move into an area of even higher shear by Monday night or early
Tuesday, and this should cause the cyclone to become a remnant low
in about 36 hours.  Thereafter, the cyclone is forecast to gradually
spin down and dissipate by day 3 as indicated by the global models.
 
Andres has moved a little more westerly over the past 12-24 hours 
than anticipated, but a longer term motion is northwestward or 
305/5 kt. The track guidance insists that the cyclone will gain 
more latitude during the next day or so, before it weakens and 
becomes vertically shallow.  Once that occurs Andres should turn 
westward within the low-level flow.  The latest NHC track forecast 
has been adjusted south and west of the previous track during the 
first 12-24 hours, due to the more westward initial position.  
Thereafter, it is similar to the previous NHC advisory, and is in 
best agreement with the GFS and GFS-ensemble mean models.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0300Z 14.3N 109.0W   35 KT  40 MPH
 12H  10/1200Z 14.8N 109.4W   30 KT  35 MPH
 24H  11/0000Z 15.4N 109.9W   30 KT  35 MPH
 36H  11/1200Z 15.8N 110.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  12/0000Z 15.9N 111.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  12/1200Z 15.9N 112.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  13/0000Z...DISSIPATED
 
$$
Forecaster Brown
 
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