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Tropical Depression Sixteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP162022
1000 PM CDT Wed Sep 28 2022
The area of low pressure located south of the southwestern coast of
Mexico has steadily gained organization throughout the day. Recent
microwave imagery indicated the formation of convective banding and
an earlier partial ASCAT pass suggested the system likely has a
well-defined center. Recent Dvorak classifications from TAFB and SAB
were both 2.0, another sign that the system has become better
organized. Collectively these data support classifying the system as
a tropical cyclone, and advisories have been initiated on Tropical
Depression Sixteen.
For the next 48 to 60 h, the forecast is fairly straightforward with
high confidence. The depression is moving toward the west-northwest
near 9 kt, and that general motion should continue as the system is
steered by a mid-level ridge centered over Mexico. Environmental
conditions appear conducive for strengthening, and all of the
intensity models suggest it will become a tropical storm quickly,
and continue strengthening to hurricane intensity a day or two after
that.
The main concern with the forecast is what happens beyond 60 h, when
confidence in the forecast decreases considerably. There is a clear
bifurcation in the track guidance at that point that appears to be
linked to the intensity and vertical extent of the cyclone. If the
cyclone is relatively deep at that point, which is shown by all of
the normally reliable intensity guidance, it will likely turn
northward or north-northeastward as it interacts with a mid- to
upper-level trough. However, some models like the ECMWF forecast a
shallower cyclone that takes a drastically different path slowly
westward, steered primarily by lower-level winds. The result is a
massive spread in the track guidance, with most of the consensus
aids caught somewhat between those two scenarios. Although the ECMWF
solution can not be dismissed entirely, the more skillful intensity
guidance (supported by the favorable environment) suggest that the
eastern solution toward Mexico may be more likely. The NHC forecast
therefore favors the northeastern solution and shows the cyclone
moving toward the coast of Mexico by 72-96 h. Strong upper-level
winds associated with the aforementioned trough and a drier
surrounding environment should cause the cyclone to weaken as it
moves closer to the coast, and it will likely quickly dissipate if
it moves inland. The NHC intensity forecast is close to the
intensity consensus throughout the forecast, except at 96 h to
reflect that the official forecast position is still over water at
that time.
FORECAST POSITIONS AND MAX WINDS
INIT 29/0300Z 14.4N 103.7W 30 KT 35 MPH
12H 29/1200Z 15.1N 105.3W 35 KT 40 MPH
24H 30/0000Z 16.1N 107.1W 45 KT 50 MPH
36H 30/1200Z 16.8N 108.3W 55 KT 65 MPH
48H 01/0000Z 17.5N 108.5W 65 KT 75 MPH
60H 01/1200Z 18.5N 108.1W 70 KT 80 MPH
72H 02/0000Z 19.7N 107.7W 75 KT 85 MPH
96H 03/0000Z 23.0N 107.0W 60 KT 70 MPH
120H 04/0000Z 25.0N 106.0W 25 KT 30 MPH...POST-TROP/INLAND
$$
Forecaster D. Zelinsky
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