[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 012100
TCDAT3

Tropical Depression Three Discussion Number   1
NWS National Hurricane Center Miami FL       AL032020
400 PM CDT Mon Jun 01 2020

Recent satellite data and surface observations from Mexico show
that the circulation associated with the area of disturbed weather
over the Yucatan peninsula has become better defined during the
past several hours, and that the center has moved over the eastern
portion of the Bay of Campeche.  Although the deep convection has
waned somewhat, there is evidence of banding in both visible
satellite imagery and recent radar data from Sabancuy, Mexico.
Based on these data, advisories are being issued on a tropical
depression.  The initial intensity is set at 25 kt, which is in
agreement with earlier ASCAT data.

The depression will be moving over the warm waters over the Bay of
Campeche and upper-level winds are forecast to be generally
conducive for strengthening during the next couple of days. The NHC
forecast is in line with much of the intensity guidance and calls
for the system to become a tropical storm in 12 to 24 hours, with
some additional strengthening predicted through 48 hours while the
system remains over the southern Bay of Campeche.  After that time,
the system's intensity will depend on how much it interacts with
land.  Although the latest runs of the GFS and ECMWF models
take the cyclone inland over southern Mexico, the NHC forecast
keeps it just offshore and shows the cyclone maintaining tropical
storm strength.  Later in the period, the guidance suggests that
the system could strengthen over the south-central Gulf of Mexico,
but the latter portion of the intensity forecast is of low
confidence.

The depression is moving west-northwestward or 290/6 kt.  The system
has been moving cyclonically around a larger gyre over Central
America during the past couple of days, and while it remains
embedded within the gyre it is forecast to turn west-southwestward,
and then southward at a slower forward speed over the next couple of
days.  On this track, the cyclone is expected to move near the
southern Bay of Campeche coast during the next day or two, and
confidence it that portion of the track forecast is high.  After
that time, two distinct scenarios emerges. The first is that the
cyclone continues moving southward and weakens or dissipates over
the rugged terrain over southern Mexico. The latest runs of the
ECMWF and GFS favor that scenario.  In this scenario, both models
show a new system developing near the south-central Gulf of Mexico
from another vorticity center that rotates around the larger gyre.
The second scenario, favored by the UKMET and some EC ensemble
members, is for the depression to eject north-northeast moving
into the central Gulf of Mexico by day 5.  The NHC forecast favors
the latter, but it is certainly possible that this tropical cyclone
will move inland and dissipates and a new cyclone formation occurs
later this week.  The latter portion of both the track and intensity
forecast are of quite low confidence.

Key Messages:

1. The depression is expected to bring heavy rainfall to portions of
southern Mexico, Guatemala, Honduras and El Salvador, which could
cause life-threatening flash flooding and mudslides. Refer to
products from your local weather office for more information.

2. Tropical storm conditions are expected along the coast of Mexico
where a tropical storm warning is in effect.

3. The system is forecast to begin moving northward across the Gulf
of Mexico later this week. However, it is too soon to specify the
location and timing of any potential impacts along the U.S. Gulf
Coast. Interests in these areas should monitor the progress of this
system through the week and ensure they have their hurricane plan in
place as we begin the season.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 19.6N  91.2W   25 KT  30 MPH
 12H  02/0600Z 19.8N  92.3W   30 KT  35 MPH
 24H  02/1800Z 19.5N  92.8W   35 KT  40 MPH
 36H  03/0600Z 19.2N  93.0W   40 KT  45 MPH
 48H  03/1800Z 18.8N  93.2W   45 KT  50 MPH
 60H  04/0600Z 18.8N  93.2W   45 KT  50 MPH
 72H  04/1800Z 18.8N  93.2W   45 KT  50 MPH
 96H  05/1800Z 19.0N  92.8W   45 KT  50 MPH
120H  06/1800Z 23.0N  91.0W   50 KT  60 MPH

$$
Forecaster Brown
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