ZCZC MIATCDEP1 ALL
TTAA00 KNHC DDHHMM
 
Tropical Depression Eleven-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP112023
400 PM CDT Mon Sep 04 2023
 
Recent visible satellite imagery indicates that the disturbance
located south of the southwestern coast of Mexico (93E) has
developed a well-defined circulation. In addition, a prominent band
of deep convection has formed around its western half. The latest
Dvorak classification Data-T from TAFB is a 2.0, which corresponds
to 30 kt. Based on the available data, the system has been
classified as Tropical Depression Eleven.
 
The depression is moving westward, with an estimated forward speed
of 10 kt. While all models agree that the cyclone will head
generally west-northwestward for the next 5 or more days, moving
well south and west of Mexico, there is substantial disagreement on
its forward speed. The main source of this uncertainty appears to be
differences in the strength of the primary steering mechanism
influencing the depression, a deep ridge centered over northern
Mexico and the southwestern U.S. that extends over the eastern
Pacific. The stronger the ridge, the faster the cyclone will move.
The uncertainty in the track forecast is much higher than normal by
the end of the forecast, with even the consensus models relatively
far apart. At day 5, the gap between HCCA and TVCN is more than 150
n mi. As a course of least regret, the NHC forecast doesn't favor
any one model or consensus aid, generally staying between the simple
and corrected consensus tracks.
 
The environment looks very conducive for strengthening, possibly
significantly so. SHIPS-derived shear is forecast to be near or
below 10 kt through day 5, with plenty of moisture and warm SSTs
available as well. It will likely take a day or so for the
depression to get sufficiently organized to take advantage of this
environment, so only slow strengthening is forecast for the first 24
h. Looking beyond that, the SHIPS-RII and DTOPS rapid
intensification (RI) probabilities for 65kt/72 h are both above 60
percent. The NHC forecast explicitly shows RI starting at 36 h and
continuing through 72 h. While there is spread at just how strong
the cyclone will get, most models suggest its peak will come between
72 and 96 h, so a peak intensity higher than what the NHC forecast
shows is definitely possible. Beginning at 96 h, the cyclone should
begin to quickly spin down as it moves over cooler waters.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/2100Z 12.5N 104.2W   30 KT  35 MPH
 12H  05/0600Z 12.8N 105.3W   35 KT  40 MPH
 24H  05/1800Z 13.3N 106.7W   40 KT  45 MPH
 36H  06/0600Z 13.9N 108.2W   50 KT  60 MPH
 48H  06/1800Z 14.6N 110.2W   60 KT  70 MPH
 60H  07/0600Z 15.5N 112.5W   80 KT  90 MPH
 72H  07/1800Z 16.5N 114.8W   95 KT 110 MPH
 96H  08/1800Z 19.0N 119.5W  100 KT 115 MPH
120H  09/1800Z 21.5N 124.5W   75 KT  85 MPH
 
$$
Forecaster D. Zelinsky
 
NNNN