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Tropical Depression Carlos Discussion Number  15
NWS National Hurricane Center Miami FL       EP032021
1100 PM HST Tue Jun 15 2021
 
Carlos has maintained a small area of deep convection to the south 
and northeast of the well-defined low-level center of circulation. 
However, the convection has decreased in coverage and has become 
more linear over the past 3 h. Despite the ragged convective 
appearance in infrared satellite imagery, ASCAT-A/-B passes at 0438Z 
and 0554Z, respectively, indicated that the small cyclone was still 
producing winds of 28-29 kt in the northwestern quadrant. Therefore, 
the intensity is being kept at 30 kt for this advisory.

Carlos is moving a little south of due west or 260/06 kt. As per the 
previous forecast discussion, a gradual westward turn is expected to 
occur later today, followed by a westward to west-northwestward 
motion thereafter as the cyclone weakens and becomes more vertically 
shallow, being steered more by the long-fetch easterly trade wind 
flow. The new NHC track forecast is essentially just an update of 
the previous advisory track and lies near a blend of the TVCE and 
NOAA-HCCA consensus track models.

The only positive factor that Carlos has going for it is the warm 
water beneath the cyclone where sea-surface temperatures (SST) are 
27.5 deg C. Surrounding the small cyclone, however, is a very dry 
and cool airmass, with stable stratocumulus clouds now wrapping into 
the system, while deep-layer vertical wind shear of more than 20 kt 
has been increasing from the west.  Although SSTs are expected to be 
warm enough to sustain a tropical cyclone for the next few days, the 
unfavorable combination of strong shear and a drier airmass is 
expected to cause Carlos to weaken and degenerate into a remnant low 
by late today, if not sooner. The NHC intensity forecast is similar 
to the previous advisory, and closely follows the HCCA and IVCN 
intensity consensus models.

FORECAST POSITIONS AND MAX WINDS
 
INIT  16/0900Z  9.2N 135.0W   30 KT  35 MPH
 12H  16/1800Z  9.2N 135.9W   25 KT  30 MPH
 24H  17/0600Z  9.2N 137.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  17/1800Z  9.4N 138.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  18/0600Z  9.6N 139.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  18/1800Z  9.8N 141.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  19/0600Z...DISSIPATED
 
$$
Forecaster Stewart
 
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