Tropical Storm Margot Discussion Number  12
NWS National Hurricane Center Miami FL       AL142023
500 AM AST Sun Sep 10 2023

Westerly shear and a slug of dry air, which was noted in the
MET-10 water vapor imagery, impedes Margot's ability to sustain
deep convection near the surface center while most convection 
remains displaced to the northeast.  A recent AMSR2 microwave pass 
confirmed that the surface center has again become exposed to the 
southwest of the convective canopy.  The initial intensity is held 
at 45 kt and is based on the TAFB and SAB Dvorak satellite 
intensity estimates. 

The aforementioned moderate shear should continue to undercut the 
diffluent southerly flow aloft during the next couple of days.  
Afterward, the statistical-dynamic SHIPS guidance indicates that 
Margot will slip under a narrow upper-level ridge, favoring 
intensification.  The only inhibiting factor during the latter part 
of the forecast appears to be a less conducive surrounding 
thermodynamic environment, which should affect the intensity rate 
some.  Therefore, only gradual strengthening is forecast and agrees 
with intensity consensus models but below the HAFS-B hurricane 
model, which predicts Margot as a hurricane on day 4.  For now, the 
official forecast shows Margot becoming a hurricane in 48 hours in 
agreement with the reliable intensity consensus aids, but this 
predicted rate of intensification could be generous.

Through the early part of this week, Margot is expected to turn
north-northwestward to northward while entering a growing weakness
in the central Atlantic subtropical ridge.  Beyond day 3, Margot 
will likely slow its forward motion in response to a building or
blocking high to the northwest.  There remains quite a bit of model 
spread/uncertainty late in the period, with the two global model 
clusters showing Margot either turning eastward or moving toward 
the northwest to west.  The NHC track forecast conservatively lies 
between the HFIP HCCA and simple consensus TVCA, which splits the 
two model cluster solutions.



FORECAST POSITIONS AND MAX WINDS

INIT  10/0900Z 22.1N  39.6W   45 KT  50 MPH
12H  10/1800Z 23.1N  40.1W   50 KT  60 MPH
24H  11/0600Z 24.8N  40.5W   55 KT  65 MPH
36H  11/1800Z 26.5N  40.7W   60 KT  70 MPH
48H  12/0600Z 28.2N  40.8W   65 KT  75 MPH
60H  12/1800Z 30.1N  40.9W   70 KT  80 MPH
72H  13/0600Z 32.4N  41.0W   70 KT  80 MPH
96H  14/0600Z 35.0N  41.6W   75 KT  85 MPH
120H  15/0600Z 36.7N  41.9W   75 KT  85 MPH

$$
Forecaster Roberts