ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
Tropical Depression Eighteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP182021
1000 AM CDT Thu Nov 04 2021
The area of low pressure we have been tracking since it formed
several days ago over the southwestern Caribbean Sea has moved
over the far eastern Pacific and gradually become better-defined
over the past couple of days. In addition, the convective
organization has steadily increased. An ASCAT-C overpass earlier
this morning showed that the surface low was slightly elongated.
However, the deep convection has persisted near, or just east of
that low for several hours since that time. First light visible
satellite imagery also indicates that the circulation is
well-defined. Therefore, advisories are being initiated for
Tropical Depression Eighteen-E. The ASCAT pass also showed peak
winds of 28 kt associated with the system, and a blend of the latest
Dvorak intensity estimates from TAFB and SAB suggest an initial
advisory intensity of 30 kt.
The initial motion of the depression is 280/7 kt. The cyclone is
located to the south of a broad mid-tropospheric ridge extending
across southern Mexico and much of the eastern Pacific basin. This
feature should steer the depression generally westward for most of
the forecast period, along with a gradual increase in forward speed.
By day 5, a turn to the west-northwest may occur, as the cyclone
becomes situated along the southwestern portion of the ridge. The
track model guidance is in good agreement on this scenario, and the
NHC track forecast is near the various multi-model consensus
solutions.
The environment surrounding and ahead of the depression appears
generally favorable for strengthening with ample atmospheric
moisture and SSTs of 27 to 28 degrees C. The only inhibiting factor
to strengthening may be the westerly shear vector, which although
should remain under 10 kt, when combined with the cyclone's
increasing westerly forward motion may cause convection to
periodically get stripped to its east of its center. Based on these
conditions, the model guidance indicates a slow and steady pace of
strengthening over the next several days, and NHC follows suit with
an intensity forecast near the IVCN and NOAA-HCCA consensus.
FORECAST POSITIONS AND MAX WINDS
INIT 04/1500Z 9.4N 90.0W 30 KT 35 MPH
12H 05/0000Z 9.6N 90.9W 30 KT 35 MPH
24H 05/1200Z 9.4N 92.0W 35 KT 40 MPH
36H 06/0000Z 9.2N 93.4W 35 KT 40 MPH
48H 06/1200Z 9.0N 95.2W 40 KT 45 MPH
60H 07/0000Z 9.0N 97.3W 40 KT 45 MPH
72H 07/1200Z 9.0N 99.6W 45 KT 50 MPH
96H 08/1200Z 9.7N 104.1W 50 KT 60 MPH
120H 09/1200Z 11.1N 108.5W 55 KT 65 MPH
$$
Forecaster Latto
NNNN