Eastern Pacific Basin Tropical Cyclones

Tropical Storm Madeline Forecast Discussion


000
WTPZ44 KNHC 190240
TCDEP4

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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