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Tropical Storm Madeline Discussion Number 6
NWS National Hurricane Center Miami FL EP142022
900 PM MDT Sun Sep 18 2022
Madeline has increased in organization over the past several hours.
The low-level center is now embedded underneath the northeastern
portion of a mass of deep convection with cloud tops as cold as -85
degrees Celsius. A recent SSMIS overpass also shows a well-defined
curved band within the western semicircle. The latest subjective
Dvorak intensity estimates from TAFB and SAB are both T-3.0, and
support raising the initial intensity to 45 kt for this advisory.
There is a small window of opportunity through Monday morning for
Madeline to strengthen a little more, as the storm begins to move
along the shear vector and remains over warm waters and within a
favorable thermodynamic environment. However, by late Monday the
cyclone is forecast to reach the 26 degrees C isotherm and begin to
move into a progressively drier and more stable environment.
Therefore, steady weakening is forecast to begin by that time. Both
the GFS and ECMWF simulated satellite suggest that Madeline will
become devoid of deep convection by Tuesday and degenerate into a
remnant low. The latest NHC intensity forecast was increased through
the next 24 h, but is the same as the previous advisory thereafter.
Madeline is continuing its slow turn to the left, and is now moving
northwestward at 8 kt to the southwest of a mid-level ridge. This
motion is beginning to increase the cyclone's distance from the
coast of southwestern Mexico. Based on this and surface
observations, the government of Mexico has discontinued the Tropical
Storm Watch that was in effect for the portion of that coastline.
Model guidance is in very good agreement that Madeline will turn to
the west-northwest on Monday night and then west by Tuesday as the
weakening cyclone becomes steered by the surrounding low-level flow.
The combination of this track and a contracting wind field should
keep tropical-storm-force winds well offshore of the southern Baja
California peninsula as the system passes to the south through
Monday night. The latest NHC track forecast is very little changed
from the previous one and lies near the various multi-model
consensus tracks.
KEY MESSAGES:
1. Heavy rains from Madeline are expected for portions of coastal
southwestern Mexico into Monday. This rainfall may produce flash and
urban flooding, along with possible mudslides in areas of higher
coastal terrain.
FORECAST POSITIONS AND MAX WINDS
INIT 19/0300Z 19.3N 107.9W 45 KT 50 MPH
12H 19/1200Z 20.1N 109.0W 50 KT 60 MPH
24H 20/0000Z 20.6N 110.3W 45 KT 50 MPH
36H 20/1200Z 21.0N 111.5W 35 KT 40 MPH
48H 21/0000Z 21.4N 112.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 21/1200Z 21.6N 114.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 22/0000Z 21.6N 115.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 23/0000Z 21.2N 118.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 24/0000Z 20.8N 120.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Latto
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