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Tropical Depression Fourteen-E Discussion Number 2
NWS National Hurricane Center Miami FL EP142021
1000 PM CDT Wed Aug 25 2021
Recent satellite imagery and microwave data indicate that the
depression has not become better organized this evening. It is
producing a ragged area of convection over the northwestern portion
of its circulation, which appears somewhat elongated along an
east-west axis. The latest UW-CIMSS objective ADT estimate and
subjective 00z Dvorak classifications from TAFB and SAB support an
initial intensity of 30 kt for this advisory.
The estimated initial motion of the poorly organized depression is
an uncertain 280/6 kt. The cyclone is being steered generally
westward along the southern extent of a mid-level ridge over the
south-central United States. A deep-layer trough over the western
U.S. is forecast to weaken the steering ridge during the next couple
of days. Thus, the depression is forecast to gain some latitude and
move west-northwestward overnight and Thursday, and then
northwestward or north-northwestward on Friday and Saturday.
Although the track guidance consensus and many GEFS and ECMWF
ensemble members still keep the center of the cyclone offshore,
there was a pronounced eastward shift in the guidance envelope this
cycle. In fact, the GFS and several GEFS members show the system
moving inland along the coast of southwestern Mexico in 2-3 days.
The official NHC track forecast has been adjusted to the right of
the previous one from 48 h onward and lies along the HFIP corrected
consensus approach (HCCA) aid. This brings the center of the cyclone
closer to the coast of southwestern Mexico, but remains offshore and
to the left of much of the latest guidance. The extended forecast
takes the system near the southern portion of Baja California Sur
early next week, but overall there is above average uncertainty in
the extended portion of the track forecast. Interests along the
coast of southwestern Mexico and in Baja California Sur should
closely monitor future updates to the forecast.
The depression is located within a favorable thermodynamic
environment for strengthening, but moderate to strong northeasterly
vertical wind shear should limit its intensification rate in the
short-term period. The shear is expected to weaken by Friday, and
the system is forecast to become a hurricane this weekend over very
warm SSTs. There remains a large amount of spread in the intensity
guidance beyond 48 h, due to the potential for land interaction
earlier in the forecast period. Since the latest NHC track forecast
keeps the system offshore, the intensity forecast is much higher
than the consensus aids during this period and trends toward the
stronger statistical-dynamical guidance. Again, confidence is lower
than normal in the day 3-5 forecast.
Key Messages:
1. The depression is forecast to strengthen to a tropical storm on
Thursday and be near hurricane intensity by Saturday. While the
core of the storm is currently expected to pass near but offshore
the southwestern coast of Mexico, strong winds and heavy rainfall,
possibly resulting in flash floods and mudslides, could affect
portions of that area over the next several days. Interests in this
area should closely monitor the progress of this system and updates
to the forecast.
2. The system is forecast to pass near the southern portion of Baja
California Sur as a hurricane early next week, bringing a risk of
wind and rain impacts to that area. Given the above average
uncertainty in the forecast, it is too soon to determine the
magnitude and location of these potential impacts.
FORECAST POSITIONS AND MAX WINDS
INIT 26/0300Z 11.9N 100.1W 30 KT 35 MPH
12H 26/1200Z 12.3N 101.2W 35 KT 40 MPH
24H 27/0000Z 13.1N 102.7W 40 KT 45 MPH
36H 27/1200Z 14.2N 103.9W 45 KT 50 MPH
48H 28/0000Z 15.6N 104.8W 55 KT 65 MPH
60H 28/1200Z 17.2N 105.6W 60 KT 70 MPH
72H 29/0000Z 18.8N 106.5W 65 KT 75 MPH
96H 30/0000Z 21.3N 108.7W 70 KT 80 MPH
120H 31/0000Z 23.0N 111.0W 60 KT 70 MPH
$$
Forecaster Reinhart/Pasch
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