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Tropical Storm Lorena Discussion Number  11
NWS National Hurricane Center Miami FL       EP122025
800 AM MST Thu Sep 04 2025

Lorena has crossed the 26C sea-surface temperature isotherm and is 
now experiencing about 20 kt of southwesterly wind shear.  Recent 
GMI and AMSR-2 microwave passes indicate that the center is now 
located near or just outside of the convective area, and the 
convection is beginning to get sheared off toward the northeast.  
The latest subjective intensity estimates from SAB and TAFB range 
from 55-77 kt, and the UW-CIMSS objective intensity estimates range 
from 50-62 kt.  The initial intensity is lowered to 60 kt for this 
advisory, making Lorena a tropical storm.  As Lorena continues to 
slowly gain latitude, it will progressively encounter colder water 
temperatures and stronger southwesterly shear.  The latest NHC 
intensity forecast shows fairly quick weakening to a remnant low in 
about 36 h, in agreement with the guidance.  This is a slightly 
faster rate of weakening compared to the previous official 
forecast.  The remnant low should then dissipate completely in 
about 3 days, likely offshore, to the west of Baja California.

The GFS model and all of NHC's consensus guidance (including the 
HCCA, Google DeepMind, and TCVE) have come onboard to the solution 
that the ECMWF, UKMET, and CMC models have been advertising for the 
past couple of days, which shows Lorena slowing down and dissipating 
offshore, to the west of Baja California.  The only models that 
still bring Lorena's center into the Baja California peninsula are 
the HAFS models and the HMON (as a weak low, below tropical storm 
strength).  As Lorena's convection gets stripped off toward the 
northeast, its path will soon be governed by the low-level steering 
currents, which should keep Lorena moving slowly offshore as it 
weakens.  The new NHC forecast represents a large change from the 
previous forecast, and now keeps the center of Lorena offshore.

Although the chance of sustained tropical-storm-force winds on land 
is starting to decrease, the rainfall and flash flooding threat for 
the Baja California peninsula is still significant.  Abundant 
moisture will continue to stream northeastward away from the 
cyclone.  Because of that, there is still a significant risk of 
heavy rainfall and flash flooding across portions of Baja California 
Sur, Sonora, southern Arizona and New Mexico.

 
Key Messages:
 
1. Heavy rainfall associated with Lorena will continue to impact 
Baja California Sur and Sonora Mexico through Friday. This will 
increase the risk of life-threatening flash floods and mudslides 
across northwest Mexico.
 
2. Moisture from Lorena will contribute to heavy rainfall concerns 
across Arizona and New Mexico through Saturday. Isolated to 
scattered instances of flash flooding are possible across Arizona 
into Saturday.
 
3. The center of Lorena is forecast to move parallel to, but
offshore of, the southwest coast of the Baja California Peninsula
through tonight, and then could move closer to the west-central 
coast of the peninsula while it weakens on Friday. Tropical storm 
conditions, mainly in gusts, are likely along portions of the coast 
of Baja California Sur today through Friday, where a Tropical Storm 
Warning is in effect.

4. Life-threatening surf and rip current conditions will affect
portions of the southern and western coasts of Baja California Sur
during the next couple of days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/1500Z 24.2N 114.2W   60 KT  70 MPH
 12H  05/0000Z 24.7N 114.5W   45 KT  50 MPH
 24H  05/1200Z 25.3N 114.5W   35 KT  40 MPH
 36H  06/0000Z 25.8N 114.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  06/1200Z 26.2N 114.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  07/0000Z 26.6N 114.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  07/1200Z 26.9N 114.4W   15 KT  15 MPH...POST-TROP/REMNT LOW
 96H  08/1200Z...DISSIPATED
 
$$
Forecaster Hagen/Brown
 
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