ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
Tropical Depression Nine-E Discussion Number 5
NWS National Hurricane Center Miami FL EP092022
900 AM MDT Sun Aug 07 2022
The depression remains disheveled this morning, with the center of
the system still partially exposed to the southwest of the deepest
convective activity. This structure is primarily due to dry air
being imported to the center by moderate southwesterly vertical wind
shear (VWS). Subjective Dvorak intensity estimates were T2.5/35 kt
from TAFB, T2.0/30 kt from SAB, while the latest objective estimate
from UW-CIMSS ADT was T2.5/35 kt. Given the lackluster satellite
presentation, the initial intensity was held at 30 kt for this
advisory.
The depression is now moving northwest as a slightly slower pace,
estimated at 315/10 kt. A mid-level ridge located northeast of the
system is expected to steer it generally northwestward over the next
few days. One interesting note in the immediate future is there is a
weakness in this ridge to the north, partially related to an
upper-level trough currently shearing the depression. If the system
is able to become better aligned vertically, this could lead to a
rightward shift in the short-term track. The NHC track forecast
accounts for this possibility by being located on the right side of
the track guidance envelope over the next 12-36 hours. This track is
just a bit northeast of the previous one, though it blends back
towards the consensus aids by the end of the forecast, when the
system will likely be steered by the low-level trade wind flow.
A weak upper-level trough located northwest of the depression is the
primary feature maintaining southwesterly VWS over the system. Over
the next day or so, both the GFS and ECMWF suggest this feature
should decay and shift southwest, perhaps related to convection
building up-shear around the depression while helping to align its
low and mid-level centers. Should this process occur,
intensification still appears possible. One alternate solution is
that convective outflow is not able to displace the upper-level low
and some amount of shear is maintained over the system. For now, the
latest NHC intensity forecast will maintain a peak of 45 kt in 36-48
hours, right around the time the system will be crossing the 26 C
sea surface temperature (SST) isotherm. After that time, weakening
is expected over even cooler SSTs and a more stable environment. The
system is still expected to become a post-tropical remnant low at
the end of the forecast period. This intensity forecast is on the
high side of the guidance envelope overall, but is close to the
latest HCCA consensus aid.
FORECAST POSITIONS AND MAX WINDS
INIT 07/1500Z 16.8N 109.9W 30 KT 35 MPH
12H 08/0000Z 17.9N 111.1W 35 KT 40 MPH
24H 08/1200Z 19.4N 112.6W 40 KT 45 MPH
36H 09/0000Z 20.7N 114.2W 45 KT 50 MPH
48H 09/1200Z 21.7N 115.9W 45 KT 50 MPH
60H 10/0000Z 22.5N 117.7W 40 KT 45 MPH
72H 10/1200Z 23.1N 119.3W 35 KT 40 MPH
96H 11/1200Z 24.0N 122.5W 30 KT 35 MPH
120H 12/1200Z 24.0N 125.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Papin
NNNN