Tropical Storm Ileana Forecast Discussion

000
WTPZ44 KNHC 140853
TCDEP4

Tropical Storm Ileana Discussion Number   8
NWS National Hurricane Center Miami FL       EP092024
200 AM MST Sat Sep 14 2024

Ileana continues to produce bursts of deep convection, but a 
sharpening of the west side of the cloud canopy suggests stronger 
vertical shear is setting in.  Maximum winds are still estimated to 
be 35 kt based on ASCAT data from last evening, and the fact that 
subjective and objective intensity estimates have not begun to 
decrease much quite yet.

Ileana's center is moving northward over the southern Gulf of 
California, away from southern Baja California Sur, with an initial 
motion of 360/8 kt.  A northward motion is expected to continue 
today, bringing Ileana's center near or over the coast of northern 
Sinaloa and southern Sonora around midday.  The new NHC track 
forecast is a bit to the east of the previous prediction during the 
first 12 hours or so, mainly due to an adjustment of the initial 
position.  The track guidance indicates that Ileana should slow 
down and turn north-northwestward and then northwestward tonight 
and on Sunday, generally running up the length of the Gulf of 
California.

Although deep-layer shear is beginning to increase, several models, 
including the GFS and ECMWF, indicate that Ileana could maintain 
tropical storm intensity and bring tropical storm conditions to 
portions of the northern coast of Sinaloa and southern coast of 
Sonora later this morning and early afternoon.  These same models, 
however, show Ileana's convection quickly being sheared away and 
dissipating by this evening and tonight as the cyclone moves into a 
much drier air mass.  As a result, the NHC forecast shows Ileana 
degenerating into a remnant low in about 24 hours, with the remnant 
low dissipating over the central Gulf of California by early Monday.


Key Messages:

1. Tropical Storm Ileana will bring heavy rainfall to portions of 
western Mexico through this weekend. This heavy rainfall will bring 
a risk of flash flooding and mudslides to portions of the area. 

2. Tropical storm conditions are expected within the warning area 
of northern Sinaloa and southern Sonora later this morning and 
afternoon.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0900Z 24.3N 109.2W   35 KT  40 MPH
 12H  14/1800Z 25.1N 109.3W   35 KT  40 MPH
 24H  15/0600Z 25.9N 109.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  15/1800Z 26.6N 110.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  16/0600Z 27.4N 111.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  16/1800Z...DISSIPATED

$$
Forecaster Berg