[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 231438
TCDAT4

Tropical Storm Cindy Discussion Number   6
NWS National Hurricane Center Miami FL       AL042023
1100 AM AST Fri Jun 23 2023

Cindy appears to be gradually strengthening this morning. A curved
band formed overnight to the west of the center and has wrapped
around on its southern semicircle. A SSMIS microwave pass at 1003
UTC also showed this band with the center becoming more embedded
within the larger cirrus canopy. Subjective Dvorak estimates were
T3.0/45-kt from SAB and T3.5/55-kt from TAFB. The latest objective
intensity estimates were a little on the lower side with 41 kt from
ADT and 39 kt from SATCON. We also recently received a partial
ASCAT-B pass at 1233 UTC, but it likely did not capture the highest
winds on the northeast side of Cindy's circulation. A blend of the
subjective and objective intensity guidance supports a current
intensity of 45-kt for this advisory.

It seems that Cindy has a 24-h window to intensify further, while
vertical wind shear (both deep-layer and mid-level) remains under
15 kt as the storm traverses 27-28 C sea-surface temperatures in a
marginally moist mid-level air environment. However, beyond that
period, shear out of the northwest increases markedly as the system
approaches the same upper-level trough shearing Bret, and this
increase in shear is likely to import drier mid-level air from that
direction. The intensity guidance is largely in agreement that Cindy
will intensify for the next day or so, but are in less agreement of
how quickly the storm will weaken after the shear increases. Given
the small size of Cindy, it seems more likely to be adversely
affected by the expected negative environmental conditions and
steady weakening is forecast beyond that time, with the system
likely becoming a remnant low sometime in the 4-5 day time frame.
This intensity forecast is a little bit under the HCCA and IVCN
consensus aids after 24 h.

Cindy continues to move to the west-northwest at around 290/14 kt.
This general motion is forecast to continue for the next few days as
Cindy moves around a mid-level ridge centered to its east-northeast.
Even though a weakness in the ridge is forecast to become more
pronounced north of Cindy in the 3-5 day time period, the system is
also forecast to become more vertically shallow, and be more steered
by low-level ridging which will remain in place. The latest track
aid guidance shifted ever so slightly northward compared to the
previous cycle, and the new track forecast was shifted a little
in that direction. This track forecast is a bit south of the
consensus aids, but assumes Cindy will likely be a more shallow
system by the end of the period. Cindy's track forecast remains
well to the northeast of the northern Leeward Islands.


FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 12.5N  48.0W   45 KT  50 MPH
 12H  24/0000Z 13.6N  50.0W   50 KT  60 MPH
 24H  24/1200Z 15.2N  52.5W   55 KT  65 MPH
 36H  25/0000Z 16.9N  55.2W   50 KT  60 MPH
 48H  25/1200Z 18.7N  57.7W   45 KT  50 MPH
 60H  26/0000Z 20.2N  60.0W   40 KT  45 MPH
 72H  26/1200Z 21.8N  62.2W   35 KT  40 MPH
 96H  27/1200Z 24.0N  64.9W   30 KT  35 MPH
120H  28/1200Z 26.7N  68.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin
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