Eastern Pacific Basin Tropical Cyclones

Tropical Storm Madeline Forecast Discussion


000
WTPZ44 KNHC 180239
TCDEP4

Tropical Storm Madeline Discussion Number   2
NWS National Hurricane Center Miami FL       EP142022
900 PM MDT Sat Sep 17 2022

Madeline has changed little in appearance since earlier today. 
Moderate east-northeasterly vertical wind shear of 15-20 kt is 
keeping the center of circulation at the northeastern edge of 
the cyclone's deep convection. With the lack of any appreciable 
change to Madeline's structure, the initial advisory intensity is 
being kept at 40 kt for continuity.

The storm has made its anticipated acceleration to the north and is 
now moving at about 8 kt. A mid-level ridge over the Atlantic 
should keep Madeline on a northward to northwestward track for the 
next day or so. By Tuesday, another ridge building over Texas 
should cause the cyclone to turn westward. There was very little 
change to the latest NHC track forecast from the previous one, 
which lies near the various multi-model consensus tracks. It should 
be noted that there is over 300 n mi north to south model spread 
by day 4. Therefore, the track forecast during days 4-5 is of lower 
confidence.

Madeline's intensity forecast is fairly straightforward for the next 
few days, but is more complicated thereafter due to the uncertain 
track forecast. The moderate shear affecting the storm now is 
forecast to persist through early next week while the system remains 
embedded in a moist thermodynamic environment. The combination of 
these conditions should allow for some slight strengthening over the 
next couple of days. By 48 h, the SSTs beneath Madeline are expected 
to decrease to near 26 degrees Celsius, which in combination with 
the shear, should cause the system to begin weakening around that 
time.  By late in the forecast period, the shear is forecast to 
decrease while warmer waters are present just to the south of the 
forecasted path of the cyclone. Therefore, a deviation to the left 
of the forecast track could put Madeline in a more favorable 
environment for strengthening. However, the models suggest that 
regardless of the water temperatures, Madeline is expected to 
encounter drier and more stable air later in the forecast period. 
Based on these conditions, the NHC intensity forecast was lowered 
slightly from the previous one, and is near the various consensus 
aids. The latter part of the current intensity forecast is also low 
confidence.


FORECAST POSITIONS AND MAX WINDS

INIT  18/0300Z 16.9N 106.8W   40 KT  45 MPH
 12H  18/1200Z 18.0N 107.3W   40 KT  45 MPH
 24H  19/0000Z 19.2N 108.2W   45 KT  50 MPH
 36H  19/1200Z 20.0N 109.3W   45 KT  50 MPH
 48H  20/0000Z 20.5N 110.6W   45 KT  50 MPH
 60H  20/1200Z 20.6N 111.8W   40 KT  45 MPH
 72H  21/0000Z 20.7N 113.0W   35 KT  40 MPH
 96H  22/0000Z 20.7N 115.5W   35 KT  40 MPH
120H  23/0000Z 20.7N 118.4W   35 KT  40 MPH

$$
Forecaster Latto



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