[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 311445
TCDAT5

Tropical Depression Kate Discussion Number  14
NWS National Hurricane Center Miami FL       AL102021
1100 AM AST Tue Aug 31 2021

Strong west-northwesterly shear continues to displace the limited
convective activity associated with Kate well to the east of its
center, which is fully exposed and becoming less well-defined in
visible satellite imagery. A small burst of deep convection from
earlier this morning appears to be waning, as infrared cloud top
temperatures are warming to the east of Kate's center. Consensus
T2.0/30 kt Dvorak classifications from TAFB and SAB, in addition to
the latest objective UW-CIMSS ADT estimates, suggest that Kate is
now likely a tropical depression. Therefore, the initial intensity
is lowered to 30 kt for this advisory.

Kate's center has jogged a little east of due north this morning,
and its initial estimated 12-h motion is northward, or 010/4 kt. A
mid-level ridge is forecast to build to the northeast and east of
Kate later today through Wednesday, which should steer the cyclone
more north-northwestward through midweek. Then, Kate should turn
toward the north on Thursday night and early Friday within the flow
associated with a mid- to upper-level trough that will be moving
across the western Atlantic. The official NHC forecast track is very
similar to the previous one, and it lies near the reliable consensus
aids TVCA and HCCA. The only minor track adjustment has Kate turning
a little earlier and faster toward the north late this week.

Even though the vertical shear is expected to diminish over Kate
during the next 12-24 h, the cyclone remains embedded within a
relatively dry mid-level environment. This will make it difficult
for Kate to sustain enough organized convection to strengthen much.
In fact, numerous models including the GFS, HWRF, and HMON show the
low weakening in the coming days, as the model simulated satellite
imagery suggests only sporadic bursts of convection will occur even
after the shear subsides. However, the possibility of Kate briefly
re-intensifying into a weak tropical storm cannot be completely
ruled out, since the cyclone will remain over warm SSTs around 28
deg C for at least the next couple of days. The official NHC
intensity forecast remains consistent with the consensus aids IVCN
and HCCA and shows no explicit change in intensity, although some
fluctuation is possible. If Kate survives this week, the global
models indicate that it will likely open up into a trough by
Saturday morning, shortly before being absorbed by an approaching
frontal system.


FORECAST POSITIONS AND MAX WINDS

INIT  31/1500Z 23.5N  50.8W   30 KT  35 MPH
 12H  01/0000Z 24.3N  51.0W   30 KT  35 MPH
 24H  01/1200Z 25.7N  51.7W   30 KT  35 MPH
 36H  02/0000Z 27.3N  52.7W   30 KT  35 MPH
 48H  02/1200Z 29.0N  53.6W   30 KT  35 MPH
 60H  03/0000Z 30.7N  54.1W   30 KT  35 MPH
 72H  03/1200Z 32.5N  53.9W   30 KT  35 MPH
 96H  04/1200Z...DISSIPATED

$$
Forecaster Reinhart
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