####018003559####
WTPZ42 KNHC 211450

TCDEP2

 

Hurricane Norma Discussion Number  16

NWS National Hurricane Center Miami FL       EP172023

900 AM MDT Sat Oct 21 2023

 

Radar data from Los Cabos, Mexico, show the center of Norma is 

situated just west-southwest of Cabo San Lucas this morning. Surface 

observations indicate that hurricane and tropical storm conditions 

are spreading over southern portions of Baja California Sur within 

the warning areas. Earlier passive microwave images and recent radar 

data indicate convection in the southern portion of Norma's inner 

core has eroded. The hurricane is also vertically tilted due to 

southerly shear, with the low-level center displaced slightly south 

of the mid-level center. These structural changes suggest weakening 

has occurred, which is consistent with the latest subjective and 

objective intensity estimates from TAFB, SAB, and UW-CIMSS. Based on 

the blend of those estimates, the initial intensity is lowered to 85 

kt for this advisory.

 

Norma is moving just west of due north (355/7 kt) this morning. The

hurricane is expected to make landfall in the hurricane warning area

this afternoon, cross the southern portion of Baja California Sur

tonight, and emerge over the southern Gulf of California on Sunday.

Then, the weakening cyclone should turn toward the northeast and

east-northeast and slowly approach the coast of Sinaloa in western

Mexico on Sunday night into early Monday. The updated NHC track

forecast shows a slightly more gradual turn in the near term and

lies slightly west of the previous one. Norma is forecast to move

inland by early Monday and dissipate over the rugged terrain of

western Mexico by Tuesday.

 

Less favorable environmental conditions (increasing southwesterly

shear and reduced mid-level moisture) and land interaction with the

Baja California peninsula should cause Norma to continue weakening

during the next couple of days. This is consistent with the

deteriorating satellite structure of Norma and supported by all of

the latest dynamical and statistical guidance. The updated NHC

forecast is lower than the previous advisory, following the

multi-model consensus trends, but lies on the higher end of the

guidance envelope. Norma is still forecast to reach the west coast

of Mexico by early Monday as a tropical storm.

 

 

Key Messages:

 

1. Norma is expected to bring life-threatening hurricane conditions

and a dangerous storm surge to portions of the far southern Baja

California peninsula within the hurricane warning area today and

tonight.

 

2. Heavy rains from Norma will continue to impact southern portions

of Baja California Sur through Sunday, with heavy rains reaching

Sinaloa later today, continuing through Monday. This rainfall will

produce flash and urban flooding, along with mudslides in areas of

higher terrain.

 

3. Norma is forecast to approach the west coast of Mexico as a

tropical storm on Sunday night and Monday, and a Tropical Storm

Warning is in effect for a portion of that area.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  21/1500Z 22.7N 110.3W   85 KT 100 MPH

 12H  22/0000Z 23.4N 110.1W   75 KT  85 MPH...INLAND

 24H  22/1200Z 24.1N 109.4W   60 KT  70 MPH...OVER WATER

 36H  23/0000Z 24.5N 108.6W   50 KT  60 MPH

 48H  23/1200Z 24.7N 107.7W   40 KT  45 MPH...INLAND

 60H  24/0000Z 25.1N 106.8W   25 KT  30 MPH...POST-TROP/INLAND

 72H  24/1200Z...DISSIPATED

 

$$

Forecaster Reinhart