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Tropical Storm Jimena Discussion Number  12
NWS National Hurricane Center Miami FL       EP092021
1100 AM HST Thu Aug 05 2021
 
Jimena's cloud pattern, which has changed little since earlier this
morning, consists of a fragmented curved band in the northwestern
semicircle and a patch of deep convection just to the southeast of
the surface center.  The subjective Dvorak satellite intensity
estimates from TAFB and SAB remain unchanged (T2.5) and the initial
intensity is held at 35 kt.
 
Jimena has about another 12 hours or so before it traverses
decreasing (sub-25C) sea-surface temperatures, and the surrounding
environment becomes less favorable due to an intruding dry and 
stable air mass.  Increasing west-northwesterly shear is also
expected to negatively affect the cyclone beyond the 36 hour period.
The official intensity forecast, which is similar to the IVCN
intensity consensus model, indicates Jimena becoming a depression
in about 24 hours and further weakening to a remnant low on 
Saturday, and opening up into a trough of low pressure on Sunday.
 
The initial motions is estimated to be northwest, or 310/7 kt.  A
mid-tropospheric ridge situated to the northeast of the cyclone
should keep Jimena moving toward the northwest through the 48
period.  Afterward, a turn toward the west-northwest is forecast as
the vertically shallow system is steered by the low-level
environmental flow.  The NHC track forecast, once again, follows
the TVCN consensus aid closely, and is similar to the previous
advisory.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/2100Z 16.4N 137.6W   35 KT  40 MPH
 12H  06/0600Z 17.0N 138.4W   35 KT  40 MPH
 24H  06/1800Z 17.9N 139.7W   30 KT  35 MPH
 36H  07/0600Z 18.8N 141.1W   30 KT  35 MPH
 48H  07/1800Z 19.7N 142.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  08/0600Z 20.2N 143.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  08/1800Z...DISSIPATED
 
$$
Forecaster Roberts
 
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