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Subtropical Depression Four Discussion Number   2
NWS National Hurricane Center Miami FL       AL042020
1100 PM AST Mon Jun 22 2020
 
The cyclone has little or no deep convection near its center, and 
remains situated beneath an upper-level low.  Therefore, the system 
is still a subtropical cyclone and the intensity is kept at 30 kt 
in agreement with the most recent satellite classification from 
TAFB.  The 30-kt intensity was also supported by recent 
scatterometer data.  There is a small window of opportunity for 
strengthening since the system should remain over a relatively warm 
Gulf Stream eddy for 12 hours or so.  Thereafter, a weakening trend 
is expected to begin and the system should make the transition to 
an extratropical cyclone over cooler waters in 36 hours or sooner.  
The global models indicate that the system should open up into a 
trough  in a couple of days so the official forecast shows 
dissipation by 72 hours.  It would not be surprising if the system 
meets its demise sooner than that.  The official intensity forecast 
is similar to the latest decay-SHIPS guidance.

The motion continues east-northeastward, or 060/9 kt.  Over the 
next few days, the cyclone should remain embedded in a branch of 
west-southwesterlies that is split off from the main mid-latitude 
flow.  There is good agreement in the track guidance that the 
system will turn northeastward with some acceleration during the 
next 48-60 hours.  The official track forecast is similar to the 
previous one, and is also close to the dynamical model consensus.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0300Z 38.7N  64.6W   30 KT  35 MPH
 12H  23/1200Z 39.2N  62.9W   35 KT  40 MPH
 24H  24/0000Z 40.3N  60.6W   30 KT  35 MPH
 36H  24/1200Z 42.0N  58.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 48H  25/0000Z 44.0N  55.5W   25 KT  30 MPH...POST-TROP/EXTRATROP
 60H  25/1200Z 46.0N  52.0W   25 KT  30 MPH...POST-TROP/EXTRATROP
 72H  26/0000Z...DISSIPATED
 
$$
Forecaster Pasch
 
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