ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
Tropical Depression Four-E Discussion Number 1
NWS National Hurricane Center Miami FL EP042023
200 AM PDT Fri Jul 21 2023
Convection associated with an area of low pressure located nearly
1000 miles southwest of the southern tip of the Baja California
peninsula has noticeably increased since last night. Earlier
last-light visible satellite imagery showed a well-defined
low-level circulation before deep convection formed and persisted
directly over it. The system therefore meets the criteria for a
tropical cyclone, and advisories have been initiated on Tropical
Depression Four-E. The initial intensity is a conservative 30 kt,
based on the satellite trends and a subjective satellite intensity
estimate from TAFB of T2.5.
The depression is being sheared by strong upper-level westerly winds
which are forecast to increase during the next few days. The system
is also crossing over a gradient of sea surface temperatures towards
cooler waters. Given these marginal conditions and global model
guidance it is likely the depression will be short-lived. The
official intensity forecast shows the cyclone gradually weakening,
becoming a remnant low by 48 h, and dissipating by 60 h. However,
some models suggest it could weaken and dissipate sooner.
The system is moving west-northwestward at 9 kt. A ridge centered
over the southwestern United States should continue to steer the
depression with this general motion for the next day or so.
Afterward, the shallow vortex is expected to turn westward in the
low-level flow. The NHC track forecast lies near the center of the
model guidance, which is generally in good agreement, and closest to
the simple consensus aid, TVCE.
FORECAST POSITIONS AND MAX WINDS
INIT 21/0900Z 14.5N 122.2W 30 KT 35 MPH
12H 21/1800Z 15.3N 123.9W 30 KT 35 MPH
24H 22/0600Z 16.1N 126.3W 30 KT 35 MPH
36H 22/1800Z 16.4N 128.5W 25 KT 30 MPH
48H 23/0600Z 16.7N 130.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 23/1800Z...DISSIPATED
$$
Forecaster Bucci
NNNN