Tropical Storm Ileana Forecast Discussion

000
WTPZ44 KNHC 132041
TCDEP4

Tropical Storm Ileana Discussion Number   6
NWS National Hurricane Center Miami FL       EP092024
200 PM MST Fri Sep 13 2024

Satellite imagery and radar data from Cabo San Lucas indicate that 
Ileana remains poorly organized with poorly-defined convective 
banding around the elongated center.  The latest satellite and radar 
imagery suggests the center is just east of the latest burst of 
convection south of Cabo San Lucas, and this is in reasonable 
agreement with positions from recently received ASCAT data.  The 
scatterometer passes show 30-35 kt winds to the east of the center, 
and based on this and the possibility of undersampling, the initial 
intensity is held at a possibly generous 40 kt.

The scatterometer and and an earlier microwave image show that 
Ileana is moving slower than thought previously, and the initial 
motion is now 345/6. A slow north-northwestward to northward motion 
should continue until the cyclone dissipates, with the center 
passing near or over the southern end of the Baja California 
peninsula during the next 6-12 h and then moving over the central 
and southern Gulf of California.  The track guidance shifted a 
little to the east of the previous guidance, and the new forecast 
track is a little to the east of the previous track.

The cyclone should be moving into an environment of increasing 
southwesterly to westerly shear and a drier airmass as it moves 
into the Gulf of California.  The intensity guidance is in good 
agreement that Ileana should weaken, and the new intensity forecast 
follows this trend.  The forecast now calls for the system to become 
a depression by 36 h, a remnant low by 48 h, and dissipate by 72 h. 
It is possible that Ileana could decay to a remnant low by 36 h, as 
the GFS and ECMWF forecast the associated convection to dissipate by 
that time.


Key Messages:

1. Tropical Storm Ileana will bring heavy rainfall to portions of 
western Mexico and southern Baja California 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 to begin in portions of
Baja California Sur during the next several hours where Tropical
Storm Warnings are in effect.


FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 22.7N 109.4W   40 KT  45 MPH
 12H  14/0600Z 23.7N 109.5W   40 KT  45 MPH
 24H  14/1800Z 24.9N 109.6W   35 KT  40 MPH
 36H  15/0600Z 25.8N 110.0W   30 KT  35 MPH
 48H  15/1800Z 26.6N 110.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  16/0600Z 27.5N 111.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  16/1800Z...DISSIPATED

$$
Forecaster Beven