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Tropical Storm Mario Discussion Number  12
NWS National Hurricane Center Miami FL       EP142019
300 AM MDT Fri Sep 20 2019

Recent microwave imagery and ASCAT data indicate that Mario's center
is located a little to the southwest of previous estimates, near a
bursting area of deep convection with cloud top temperatures colder
than -80C. The initial intensity estimate remains 55 kt based on the
latest Dvorak classifications from TAFB and SAB. The UW-CIMSS
analysis shows shear currently around 5 kt, but the SHIPS analysis
is higher, showing 15 kt. Given the cloud pattern and a banding eye
feature seen in a partial GMI overpass around 0740Z, the shear looks
on the lower side of that range. The NHC intensity forecast
continues to show some strengthening in the short term. After that
time the shear increases and the cyclone will be moving into a
drier and more stable environment with decreasing SSTs. These
factors should result in gradual weakening, with remnant low status
expected by day 4. The new NHC intensity forecast is at or above the
highest guidance through 24 hours and then is a little above the
consensus aids but below the higher SHIPS and LGEM forecasts.

The initial motion estimate is a somewhat uncertain 030/4, as Mario
appears to have slowed and turned more poleward during the past few
hours. The latest global models have trended toward more interaction
between Mario and Lorena this cycle. The GFS and UKMET show a merger
of the two systems within 24 hours. Alternatively, the ECMWF shows a
weakening Mario absorbing Lorena after 48 hours near the west coast
of the Baja California peninsula with a track well east of the rest
of the guidance. The NHC forecast keeps the systems separate for
now, with Lorena shown as dissipated in 96 hours. However, a merger
is possible by 48 hours.

The new NHC track shows Mario turning northward and then
northwestward within 24 hours as a mid-level ridge builds over
northern Mexico. Late in the period, a weakening Mario is expected
to turn westward and then west-southwestward under the influence of
a large low-level ridge over the north Pacific. The new NHC track is
to the right of the TVCE consensus, but is actually bit to the left
of the previous NHC track given the initial position and motion of
the system during the past few hours. Given the uncertainty in the
degree of interaction with Lorena, confidence is low in the details
of the track forecast even within the first 48 hours, and
additional adjustments may be needed later today.

Data from the above-mentioned ASCAT pass were used to adjust the
initial 34-kt wind radii.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 17.6N 110.2W   55 KT  65 MPH
 12H  20/1800Z 18.4N 110.0W   60 KT  70 MPH
 24H  21/0600Z 19.5N 110.8W   60 KT  70 MPH
 36H  21/1800Z 20.7N 112.3W   50 KT  60 MPH
 48H  22/0600Z 21.6N 113.9W   45 KT  50 MPH
 72H  23/0600Z 24.0N 117.0W   35 KT  40 MPH
 96H  24/0600Z 24.5N 119.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  25/0600Z 24.0N 121.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan

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