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Tropical Storm Mario Discussion Number  17
NWS National Hurricane Center Miami FL       EP142019
900 AM MDT Sat Sep 21 2019

Geostationary satellite imagery shows the low-level center of Mario
is exposed to the northeast of the main convective mass, which is
the result of strong northeasterly shear.  An average of the latest
Dvorak intensity estimates, and UW-CIMSS SATCON yields an initial
wind speed of 45 kt.  Hopefully, ASCAT data will provide a better
assessment of the cyclone's intensity later today.  The vertical
shear over Mario is forecast to remain moderate to strong during
the next 24 hours while Mario heads toward cooler waters.  This
should result in gradual weakening.  After that time, the shear is
forecast to decrease but the system will be moving into a more
stable air mass and reach the 26C isotherm by 48 hours.  Continued
weakening is forecast and Mario is forecast to degenerate into a
remnant low in a couple of days.

Mario is progressing slowly north-northwestward, or 330 degrees at
4 kt. The dynamical model guidance is in relatively good agreement
on a northwesterly track around the western side of a mid-level
ridge. As Mario weakens, it should turn northward and slow down
with the low-level steering flow. The latest consensus aids were a
little west of the previous track, so the latest official forecast
has been nudged in that direction.

FORECAST POSITIONS AND MAX WINDS

INIT  21/1500Z 18.9N 110.5W   45 KT  50 MPH
 12H  22/0000Z 19.9N 111.1W   40 KT  45 MPH
 24H  22/1200Z 21.1N 112.0W   35 KT  40 MPH
 36H  23/0000Z 22.4N 113.0W   30 KT  35 MPH
 48H  23/1200Z 23.6N 113.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  24/1200Z 25.2N 114.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  25/1200Z...DISSIPATED

$$
Forecaster Brown

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