####018002778####
WTPZ42 KNHC 180856

TCDEP2

 

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