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Tropical Storm Norma Discussion Number   3
NWS National Hurricane Center Miami FL       EP172023
300 AM MDT Wed Oct 18 2023
 
Satellite imagery shows Norma quickly becoming better organized. The 
Central Dense Overcast is continuing to expand, with cold cloud top 
temperatures of less than -90 degrees C.  A recent ASCAT pass over 
the eastern edge of the storm suggested that the low-level center 
was near the southeastern side of the deepest convection.  The 
initial intensity is set at 55 kt, in agreement with the latest 
subjective and objective Dvorak classifications from TAFB and 
UW-CIMSS ADT, respectively.
 
Norma appears to be gradually turning, and the latest motion is 
estimated to be 320/6 kt.  A weak ridge over Mexico is expected to 
steer the storm north-northwestward to northward for about 3 days.  
There is still significant uncertainty in the track prediction later 
in the forecast period, which is likely related to the anticipated 
vortex depth.  Global models that show a weaker cyclone, such as the 
ECMWF, turn the system westward prior to the Baja California 
peninsula.  Model guidance with a stronger, deeper circulation tend 
to bring the storm farther north and turn it eastward by the end of 
the forecast period.  The updated official track forecast is very 
similar to the previous prediction and is close to the simple model 
consensus aid, TVCE.  However, there is low confidence in this 
forecast given the spread in the model tracks.

Environmental and oceanic conditions are likely to remain conducive 
for additional strengthening through the next day or so.  
Statistical indices predicting the probability of rapid 
intensification, such as SHIPS-RI and DTOPS, suggest a very high 
likelihood of rapid strengthening within 24 hours.  The latest NHC 
intensity forecast explicitly shows rapid intensification, with a 
peak of 100 kt by 36 h.  By day 2, global model guidance shows that 
the deep-layer vertical wind shear should increase over the storm 
and likely induce a gradual weakening trend through the remainder of 
the forecast period.  The official forecast remains near or above 
the intensity model consensus aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 14.2N 107.9W   55 KT  65 MPH
 12H  18/1800Z 15.0N 108.1W   70 KT  80 MPH
 24H  19/0600Z 16.2N 108.3W   85 KT 100 MPH
 36H  19/1800Z 17.0N 108.5W  100 KT 115 MPH
 48H  20/0600Z 17.9N 108.9W   95 KT 110 MPH
 60H  20/1800Z 18.9N 109.4W   90 KT 105 MPH
 72H  21/0600Z 20.0N 109.8W   85 KT 100 MPH
 96H  22/0600Z 22.1N 110.1W   80 KT  90 MPH
120H  23/0600Z 22.9N 109.4W   75 KT  85 MPH
 
$$
Forecaster Bucci
 
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