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Tropical Storm Bret Discussion Number   2
NWS National Hurricane Center Miami FL       AL032023
500 PM AST Mon Jun 19 2023
 
Satellite imagery continues to show that the system is becoming 
better organized. GOES 1-min data shows convective banding and a 
dense central overcast, with the low-level center embedded on the 
northwest side of the overcast.  Given the satellite trends and 
latest Dvorak estimates from SAB and TAFB, the initial intensity is 
set to 35 kt, and the depression is named Tropical Storm Bret.

Environmental conditions appear conducive for further strengthening 
over the next few days, with much warmer than normal SSTs along with 
plentiful mid-level moisture and light shear.  The NHC forecast 
continues to show a gradual increase in wind speed, similar to the 
model consensus.  However, vertical wind shear is forecast to 
increase by most of the model guidance on day 3 in response to an 
upper-level trough, along with more dry air nearby. Thus, the NHC 
forecast shows a slow weakening after that point while Bret is 
over the eastern Caribbean. There continues to be larger than usual 
uncertainty, due to the wide spread between the stronger regional 
hurricane models and weaker global guidance.

The initial motion estimate is 280/18 kt.  A large ridge of high 
pressure over the central Atlantic Ocean is forecast to cause Bret 
to move westward over the next several days. As the system nears the 
Lesser Antilles late this week, the ridge should weaken, causing the 
storm to move more toward the west-northwest.  The main source of 
track uncertainty continues to be tied to how strong Bret becomes, 
with the models farthest to the right (HWRF, HAFS) being stronger 
than the consensus, while the left-leaning models (ECMWF, UKMET) 
showing significant weakening at long range.  Given the large track 
and intensity spread, the NHC forecast remains near the model 
consensus, only a bit faster than the previous cycle. The latest
forecast remains a low confidence prediction.
 

KEY MESSAGES:
 
1. Bret is forecast to strengthen and move across the Lesser 
Antilles as a hurricane on Thursday and Friday, bringing a
risk of flooding from heavy rainfall, hurricane-force 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  19/2100Z 11.3N  42.2W   35 KT  40 MPH
 12H  20/0600Z 11.7N  44.8W   40 KT  45 MPH
 24H  20/1800Z 12.2N  47.7W   50 KT  60 MPH
 36H  21/0600Z 12.7N  50.3W   60 KT  70 MPH
 48H  21/1800Z 13.2N  52.9W   65 KT  75 MPH
 60H  22/0600Z 13.7N  55.5W   70 KT  80 MPH
 72H  22/1800Z 14.3N  58.3W   70 KT  80 MPH
 96H  23/1800Z 15.5N  63.6W   65 KT  75 MPH
120H  24/1800Z 17.0N  68.5W   60 KT  70 MPH
 
$$
Forecaster Blake/Kelly
 
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