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Tropical Storm Bret Discussion Number   4
NWS National Hurricane Center Miami FL       AL032023
500 AM AST Tue Jun 20 2023

Although Bret remains a well-organized tropical cyclone on satellite 
imagery, its overall appearance has changed little since yesterday 
evening.  The cloud pattern consists of a developing CDO with some 
banding features mainly over the eastern portion of the circulation. 
 Cirrus motions show that the upper-level anticyclonic outflow 
pattern remains well-defined.  Subjective Dvorak intensity estimates 
from TAFB and SAB remain at 35 kt, and objective ADT estimates from 
UW-CIMMS are also near this value.  Therefore, the advisory 
intensity is held at 35 kt at this time.

Bret continues to move slightly north of due west or at about 280/15 
kt.  A mid-level high pressure area is expected to remain positioned 
to the north of the tropical cyclone for the next few days.  Thus, 
little change to the motion is likely through 72-96 hours.  In the 
latter part of the forecast period, a mid-tropospheric trough near 
the Florida peninsula should cause the deep layer ridge to weaken 
somewhat.  However, it is assumed that the cyclone will be weakening 
by that time and steered more by the low-level easterlies.  There 
continues to be a significant spread in the 3-5 day track model 
guidance, probably due in large part to differences in the predicted 
intensity of Bret.  The official track forecast is similar to the 
previous one except a little farther to the south near the end of 
the period.  The simple and corrected consensus model solutions are 
even farther to the south.

Both the atmospheric and oceanic environment look conducive for 
strengthening during the next couple of days with low shear and 
abnormally warm ocean waters.  Therefore, the forecast continues to 
call for Bret to become a hurricane in a couple of days.  By 72 
hours, however, vertical shear is predicted to increase in 
association with an upper-level trough over the eastern Caribbean 
and drier mid-level air should begin to get entrained into the 
system.  This will likely cause a weakening trend to commence after 
Bret moves into the Caribbean as suggested by the global models.  
The official intensity forecast is similar to the previous NHC 
prediction and is above the model consensus and the SHIPS/LGEM 
guidance.


KEY MESSAGES:
 
1. Bret is forecast to initially strengthen and then move across
the Lesser Antilles near hurricane intensity on Thursday and
Friday, bringing a risk of flooding from heavy rainfall, strong
winds, and dangerous storm surge and waves.
 
2. Given the larger than usual uncertainty in the track forecast,
it is too early to specify the location and magnitude of where
these hazards could occur. However, everyone in the Lesser
Antilles, Puerto Rico, and the Virgin Islands should closely monitor
updates to the forecast for Bret and have their hurricane
plan in place.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 11.7N  44.7W   35 KT  40 MPH
 12H  20/1800Z 12.1N  46.9W   45 KT  50 MPH
 24H  21/0600Z 12.6N  49.7W   55 KT  65 MPH
 36H  21/1800Z 13.1N  52.4W   60 KT  70 MPH
 48H  22/0600Z 13.5N  55.0W   65 KT  75 MPH
 60H  22/1800Z 13.9N  57.8W   65 KT  75 MPH
 72H  23/0600Z 14.3N  60.4W   60 KT  70 MPH
 96H  24/0600Z 15.0N  65.8W   55 KT  65 MPH
120H  25/0600Z 16.0N  70.5W   50 KT  60 MPH
 
$$
Forecaster Pasch
 
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