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Tropical Depression Twenty-Five-E Discussion Number 1
NWS National Hurricane Center Miami FL EP252018
300 PM MDT Fri Nov 02 2018
Microwave data received during the past several hours indicate that
the broad area of low pressure we've been monitoring southwest of
the coast of Mexico has developed a sufficiently well-defined center
of circulation and improved low-level curved bands. Visible images,
however, still suggest that multiple swirls are revolving around a
common center, with the deepest convection offset to the east of
that center due to southwesterly shear. Now that the system has a
well-defined center, advisories are being initiated on Tropical
Depression Twenty-Five-E, with maximum winds of 30 kt based on
Dvorak classifications of T2.0 and T1.5.
Although the depression should remain over sufficiently warm waters
to support strengthening, southwesterly shear is expected to
increase from its current value of about 15 kt to over 25 kt during
the next couple of days. Therefore, only some intensification is
anticipated during the next 36 hours or so, with weakening beginning
by day 3. The system is likely to degenerate into a remnant low in
4 or 5 days once it can no longer produce organized deep convection.
The statistical-dynamical guidance show little to no strengthening,
so this initial forecast most closely follows the HWRF, HCCA, and
GFS models.
The depression appears to be moving east-northeastward, or 75
degrees, at about 7 kt. The depression is trapped between two
mid-tropospheric ridges to its east and west, and to the south of an
expansive mid-level trough which extends across much of Mexico and
the Gulf of Mexico. The resulting steering pattern should cause the
cyclone to move slowly northeastward and then northward toward the
trough during the next 48 hours, but the system should then turn
sharply westward on days 4 and 5 once it becomes a shallower system
and is steered by lower-level easterly flow. The UKMET model is the
main outlier among the model guidance, showing the system reaching
the coast of southwestern Mexico, but it appears to keep the
circulation too deep in the face of strong southwesterly shear. The
NHC track forecast is therefore just slightly left of the TVCN
multi-model consensus and the HCCA model, keeping the cyclone well
offshore of the coast of Mexico.
FORECAST POSITIONS AND MAX WINDS
INIT 02/2100Z 14.4N 109.0W 30 KT 35 MPH
12H 03/0600Z 14.7N 108.3W 35 KT 40 MPH
24H 03/1800Z 15.2N 107.6W 40 KT 45 MPH
36H 04/0600Z 15.9N 107.1W 45 KT 50 MPH
48H 04/1800Z 16.7N 107.0W 45 KT 50 MPH
72H 05/1800Z 17.5N 107.4W 35 KT 40 MPH
96H 06/1800Z 17.8N 109.0W 30 KT 35 MPH
120H 07/1800Z 18.0N 111.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Berg
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