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Tropical Storm Martin Forecast Discussion


952 
WTNT41 KNHC 020846
TCDAT1

Tropical Storm Martin Discussion Number   4
NWS National Hurricane Center Miami FL       AL162022
500 AM AST Wed Nov 02 2022

Deep convection has continued to increase in coverage and intensity 
with Martin this morning, with occasional hints of a eye trying to 
develop within the cyclonically rotating bands of cloud tops colder 
than -60C. This improved core structure can also be seen on a recent 
0732 UTC GMI microwave pass. Earlier scatterometer imagery mostly 
missed the center, though the edge values of ASCAT-C in the 
southwest quadrant did show a peak wind retrieval of 44 kt. While 
earlier subjective satellite intensity estimates remained largely 
unchanged, given the improvement in satellite imagery seen this 
morning compared to last night, the initial intensity is being 
nudged upward to 55 kt for this advisory. 

Martin is starting to make the turn more northward as it accelerates 
at 075/13 kt. The tropical cyclone should continue to turn more 
northeastward and accelerate over the next 12 to 24 hours as it 
becomes captured by pronounced deep-layer trough in Atlantic Canada 
that is quickly amplifying towards the system. This same trough will 
ultimately fully capture Martin, leading to its extratropical 
transition. The merger of both systems is also forecast to lead to a 
rapid expansion of both the 34- and 50-kt radii and these have been 
increased significantly as Martin becomes extratropical. After this 
trough-TC merger, the resulting extratropical cyclone will slow down 
and then pivot eastward over the remainder of the forecast period. 
The track guidance is tightly clustered early on, but is also 
slightly east of the prior forecast track, so the latest track 
forecast was shifted in that direction. Another eastward adjustment 
was also made in days 4 and 5, in order to match closer with track 
guidance this cycle.  

Martin is having no issues maintaining moderate to deep convection 
near its center, thanks in large part to very cold (-57 to -59 
degree C) 200 mb temperatures over the cyclone maintaining 
instability. Even though shear is forecast to increase over the next 
24 hours, this negative factor will likely be offset by a pronounced 
jet streak developing north of Martin, with the cyclone being 
optimally placed for in its right entrance region, favoring 
large-scale ascent. Thus, Martin is expected to intensify further 
and is forecast to become a hurricane later today. The acceleration 
in the cyclone's forward motion may also help to increase its 
maximum sustained winds, and the latest NHC intensity forecast still 
shows Martin peaking in intensity as it becomes a large and powerful 
extratropical cyclone. This intensity forecast remains in good 
agreement with the bulk of the intensity guidance. 


FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 35.3N  52.1W   55 KT  65 MPH
 12H  02/1800Z 36.6N  49.2W   65 KT  75 MPH
 24H  03/0600Z 40.6N  43.7W   75 KT  85 MPH
 36H  03/1800Z 47.4N  37.4W   80 KT  90 MPH...POST-TROP/EXTRATROP
 48H  04/0600Z 54.3N  34.0W   75 KT  85 MPH...POST-TROP/EXTRATROP
 60H  04/1800Z 57.0N  35.3W   65 KT  75 MPH...POST-TROP/EXTRATROP
 72H  05/0600Z 55.5N  34.4W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  06/0600Z 54.4N  22.4W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  07/0600Z 57.7N  13.1W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin




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