Official Discussion issued by the National Hurricane Center

Margot (AL142023) DATA RELEASED: 9/16/2023 9:00:00 AM UTC

Copy of official data

Tropical Storm Margot Discussion Number  36
NWS National Hurricane Center Miami FL       AL142023
900 AM GMT Sat Sep 16 2023

This morning, Margo's structure on satellite imagery has degraded 
some. Cloud top temperatures surrounding the tropical cyclone have 
been gradually warming, and there is evidence of northerly vertical 
wind shear beginning to impinge on the storm due to flow from a 
poleward amplifying upper-level anticyclone. The subjective 
intensity estimates from TAFB and SAB have been slowly decreasing, 
though the AiDT, D-PRINT, & D-MINT estimates remain a bit higher. A 
compromise of these various data support a slightly weaker intensity 
of 50 kt on this advisory. 

Margot continues to execute a slow clockwise turn, with the 
estimated motion now southwestward at 220/6 kt. A gradual turn to 
the west and then northwest is anticipated over the next 24-36 hours 
as the cyclone rounds the southern periphery of a mid-level ridge 
shifting gradually northeast of Margot. It is interesting to note 
that Margot's track evolution over the last several days appears to 
have been remotely influenced by Lee, where mid-level height rises 
north of the tropical storm are in part related to diabatic ridge 
building downstream of Lee. Ultimately the same trough that is 
phasing with post-tropical cyclone Lee will pick up Margot as well, 
with the cyclone turning northeast and even eastward by the end of 
the forecast. The latest track forecast is not far off the previous 
forecast, but a little farther to the south and west over the first 
day or so, adjusting a bit towards the reliable consensus aids. 

The vertical wind shear diagnosed by SHIPS guidance is not expected 
to abate much over the next 24 hours, and Margot will be moving over 
its own cold wake it previously generated along its forecast track. 
Thus, weakening is anticipated, and simulated satellite imagery from 
both the GFS and ECMWF suggest that the cyclone may cease to produce 
enough convection to qualify as a tropical cyclone sometime in the 
36-48 hour period, though this is not explicitly shown. However, 
most of the guidance agrees a favorable trough interaction may 
result in a convective resurgence in the 60-72 h time period, and 
the latest intensity forecast shows some re-intensification during 
that time period. The trough is expected to ultimately leave behind 
Margot, with increasing shear and cooler sea-surface temperatures 
likely to result in the system becoming a post-tropical cyclone for 
good in the day 4-5 day time period.


INIT  16/0900Z 35.0N  38.3W   50 KT  60 MPH
12H  16/1800Z 34.5N  39.4W   45 KT  50 MPH
24H  17/0600Z 34.3N  41.1W   40 KT  45 MPH
36H  17/1800Z 34.8N  42.5W   35 KT  40 MPH
48H  18/0600Z 36.0N  43.3W   35 KT  40 MPH
60H  18/1800Z 37.7N  41.9W   40 KT  45 MPH
72H  19/0600Z 38.9N  39.3W   45 KT  50 MPH
96H  20/0600Z 38.5N  33.0W   35 KT  40 MPH...POST-TROPICAL
120H  21/0600Z 38.5N  29.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

Forecaster Papin