ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

Hurricane Lorena Discussion Number   7
NWS National Hurricane Center Miami FL       EP152019
1000 PM CDT Wed Sep 18 2019

Earlier microwave imagery showed that Lorena's structure has
continued to improve, with a well-defined low-level ring noted in
the 37-GHz channel.  The convective signature in infrared satellite
imagery is somewhat ragged, although it appears that a warm spot
may be developing near the estimated center.  Objective SATCON and
ADT intensity estimates are 66 kt and 75 kt, respectively, which is
higher than the 55-kt subjective estimates from TAFB and SAB.
However, given the improved microwave pattern, the initial
intensity hedges toward the objective numbers, making Lorena a
65-kt hurricane.

Both the track and intensity forecast hinge on whether Lorena
survives its fly-by of the coast of Mexico.  If the center stays
just offshore, which several of the models show, then a
strengthening ridge over northern Mexico should steer the cyclone
northwestward and west-northwestward away from west-central Mexico
after 24 hours, heading in the general direction of the southern
tip of the Baja California peninsula.  The ECMWF is the only model
at the moment that shows Lorena's center moving inland, or
interacting with the high terrain enough, to dissipate within the
next 12-24 hours.

All that being said, the NHC track forecast assumes that Lorena
will survive the next 24 hours, and it has been nudged southwestward
beyond 36 hours, close to the multi-model consensus aids and the
HCCA model.  Based on this track, environmental conditions appear
favorable for further strengthening during the next couple of days.
Weakening should commence by day 3 once the system encounters areas
of higher shear and significantly lower oceanic heat content values.

As already insinuated above, due the potential for land interaction
within the next 12-24 hours, there is greater than usual uncertainty
in both the track and intensity forecast for Lorena through day 5.

Key Messages:

1. Lorena will be dangerously close to the coast of southwestern
Mexico tonight and on Thursday.  A hurricane warning is in effect,
and preparations to protect life in property should have been
completed.

2. Lorena is forecast to cause heavy rain over portions of the
Mexican states of Michoacan, Colima, and Jalisco during the next few
days.  This rainfall may produce life-threatening flash flooding and
mudslides.

3. Lorena could threaten the southern portion of the Baja
California peninsula as a hurricane this weekend, but the forecast
is more uncertain due to the potential for land interaction tonight
and Thursday.  Residents should ensure that their hurricane plan is
in place as watches may be required on Thursday.


FORECAST POSITIONS AND MAX WINDS

INIT  19/0300Z 18.7N 104.7W   65 KT  75 MPH
 12H  19/1200Z 19.7N 105.5W   70 KT  80 MPH
 24H  20/0000Z 20.5N 106.6W   75 KT  85 MPH
 36H  20/1200Z 21.0N 107.8W   80 KT  90 MPH
 48H  21/0000Z 21.4N 109.1W   80 KT  90 MPH
 72H  22/0000Z 22.6N 111.5W   75 KT  85 MPH
 96H  23/0000Z 24.6N 113.7W   55 KT  65 MPH
120H  24/0000Z 26.4N 115.3W   35 KT  40 MPH

$$
Forecaster Berg

NNNN