Eastern Pacific Basin Tropical Cyclones

Tropical Depression Sixteen-E Forecast Discussion


000
WTPZ41 KNHC 290240
TCDEP1

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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