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Tropical Storm Ivo Discussion Number   4
NWS National Hurricane Center Miami FL       EP092025
900 AM CST Thu Aug 07 2025
 
Finding the exact center of Ivo is tricky this morning, but my best 
guess is that its track has deviated rightward since the prior 
advisory. A pair of helpful microwave passes, an AMSR2 pass at 0850 
UTC and a SSMIS pass at 1050 UTC, showed well-defined curved banding 
on the 37-GHz to 91-GHz channels respectively. More recently, a 
visible satellite animation of 1-min GOES-19 imagery shows bursting 
convection near the estimated center. Subjective Dvorak estimates by 
TAFB and SAB were T3.0/45 kt and T2.5/35 kt respectively, with the 
objective intensity estimates ranging from 34 to 51 kt. Thus, the 
initial intensity has been bumped up to 40 kt this morning.
 
Ivo appears to be maintaining a brisk west-northwestward motion, 
estimated at 300/21 kt. This rapid forward motion is thanks in part 
to a strong and large mid-level ridge stretching across northern 
Mexico and southwestern United States. This ridge is forecast to 
move along with Ivo though it does gradually dampen out in 
magnitude. The net result of this pattern should keep Ivo on a 
general west-northwestward heading, with the cyclone turning more 
westward and slowing down towards the latter half of the forecast. 
The track guidance this cycle is a little farther north, largely a 
reflection of the farther north initial position. The latest NHC 
track forecast is also farther north roughly blending the simple and 
corrected consensus aids (TVCE and HCCA), but still remains offshore 
of Mexico, making its point of closest approach in the next 12-18 
hours.
 
The small core of Ivo likely could make it susceptible to rapid
changes in intensity, either up or down. Because vertical wind
shear is relatively low (10-15 kt), and sea surface temperatures
remain above 27 C for the next 36 hours, the NHC intensity forecast
continues to show significant intensification, making Ivo a
hurricane. Thereafter, the storm will reach a sharp sea-surface
temperature gradient, and should begin a gradual weakening trend.
Towards the end of the forecast Ivo will likely lose its remaining
deep convection over the sub 24 C waters west of Baja California,
marking its transition to a post-tropical remnant low by 96 h. The
NHC intensity forecast remains a bit on the high end of the overall
model suite.
 
Given the small radius of tropical-storm-force winds associated with 
Ivo, these winds are expected to remain offshore as it makes its 
closest approach to Mexico later today. However, heavy rain and 
rough surf are likely to occur along portions of the southwest coast 
of Mexico during the next day or so.  Outer bands of Ivo are 
expected to produce locally heavy rainfall in portions of the 
Mexican states of Guerrero, Michoacan de Ocampo and Colima through 
Friday where Flash flooding is possible.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/1500Z 17.8N 104.4W   40 KT  45 MPH
 12H  08/0000Z 19.5N 106.8W   50 KT  60 MPH
 24H  08/1200Z 20.8N 109.6W   60 KT  70 MPH
 36H  09/0000Z 21.5N 111.7W   65 KT  75 MPH
 48H  09/1200Z 21.7N 113.5W   60 KT  70 MPH
 60H  10/0000Z 21.8N 114.8W   45 KT  50 MPH
 72H  10/1200Z 22.0N 116.3W   35 KT  40 MPH
 96H  11/1200Z 22.5N 119.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  12/1200Z...DISSIPATED
 
$$
Forecaster Papin
 
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