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Tropical Storm Mario Discussion Number  11
NWS National Hurricane Center Miami FL       EP142019
900 PM MDT Thu Sep 19 2019

A new, solid burst of deep convection developed over Mario's center
a little after 2200 UTC and has persisted since that time.  As a
result, Dvorak intensity estimates went back up to T3.5/55 kt from
TAFB and SAB, and the latest UW-CIMSS SATCON estimate was 50-55 kt.
As a result, Mario's initial intensity has been brought back up to
55 kt.

Mario is essentially being pulled northeastward, or 045/8 kt,
toward the circulation of Tropical Storm Lorena.  That being said,
all the major global models are now in agreement that Mario will not
merge with Lorena, and a strengthening mid-level ridge over northern
Mexico should force Mario to turn sharply northward and then
northwestward during the next 2 days.  This northwestward motion is
likely to continue for the rest of the 5-day forecast period, with
the cyclone's forward speed slowing down on days 4 and 5 as it moves
into a weaker steering pattern.  This forecast reasoning is not too
different from the previous forecast, although the new NHC track
has been nudged a bit to the left of the previous one to account for
an overall shift in the guidance envelope.  It should be noted that
the deterministic ECMWF is an outlier and brings Mario to the Baja
California peninsula as a weakening storm, but the bulk of that
model's ensemble members favor the ocean-ward tracks shown by the
other models.  These ensemble solutions help to increase our
confidence in the NHC track forecast.

UW-CIMSS is analyzing about 5 kt of shear over Mario, and given the
expanding convective canopy over the center, this could definitely
be realistic.  The shear could remain low enough for the next day or
so to allow for some strengthening, which is shown by a number of
the intensity models, and by extension, the NHC forecast.  After
24 hours, increasing easterly shear is likely to lead to gradual
weakening, with colder waters leading to a dissipation of all
convection by day 4, if not sooner.  The NHC forecast therefore now
shows Mario degenerating into a remnant low on day 4.


FORECAST POSITIONS AND MAX WINDS

INIT  20/0300Z 17.6N 110.2W   55 KT  65 MPH
 12H  20/1200Z 18.5N 109.8W   60 KT  70 MPH
 24H  21/0000Z 19.6N 110.2W   60 KT  70 MPH
 36H  21/1200Z 20.5N 111.5W   55 KT  65 MPH
 48H  22/0000Z 21.3N 112.9W   50 KT  60 MPH
 72H  23/0000Z 23.2N 115.9W   35 KT  40 MPH
 96H  24/0000Z 24.7N 118.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  25/0000Z 24.4N 119.6W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg

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