Issued at 1100 PM HST Fri Sep 11 2026
000
WTPZ44 KNHC 120849
TCDEP4

Tropical Storm Norbert Discussion Number 11
NWS National Hurricane Center Miami FL EP142026
1100 PM HST Fri Sep 11 2026

Deep convection associated with an earlier well-established curved
band has deteriorated over the past several hours, likely due to
some mid-level dry air entrainment. A 0442 UTC scatterometer pass
indicated peak winds just above 40 kt within the northwest quadrant.
Additionally, the latest subjective Dvorak intensity estimate from
TAFB is T3.0/45 kt, with objective estimates from UW-CIMSS ranging
from 45 to 50 kt. Given these data and the degraded convective
structure, the initial intensity is lowered to a generous 50 kt.

The initial motion is west-northwestward, or 285/8 kt. The track
guidance has come into much better agreement this cycle and shows
Norbert continuing generally westward through the weekend as a low-
to mid-level subtropical ridge remains north of the cyclone. A
gradual turn toward the west-southwest is then forecast during the
early to middle portion of next week. Despite the improved agreement
among the track guidance this cycle, there has been considerable
run-to-run variability, and confidence in the forecast beyond the
weekend remains lower than normal. The NHC track forecast is largely
an update of the previous advisory and lies close to the multi-model
consensus (HCCA) and Google DeepMind ensemble mean.

Environmental conditions remain favorable for some strengthening
over the weekend, and Norbert is forecast to approach hurricane
intensity by 24 to 36 h. Thereafter, a gradual weakening trend is
forecast through the remainder of the period, likely due to a
combination of mid-level dry air entrainment and weakening
upper-level divergence. Simulated satellite imagery from both the
GFS and ECMWF broadly support this and depict Norbert struggling to
maintain organized deep convection as it moves westward to
west-southwestward next week. The latest NHC intensity forecast has
been lowered slightly from the previous advisory. It remains above
the intensity guidance envelope through the weekend, then trends
toward the middle to upper end of the guidance next week.



FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 17.1N 127.4W 50 KT 60 MPH
12H 12/1800Z 17.4N 128.8W 55 KT 65 MPH
24H 13/0600Z 17.8N 130.6W 60 KT 70 MPH
36H 13/1800Z 18.1N 132.6W 60 KT 70 MPH
48H 14/0600Z 18.4N 134.7W 55 KT 65 MPH
60H 14/1800Z 18.4N 137.0W 50 KT 60 MPH
72H 15/0600Z 18.3N 139.4W 50 KT 60 MPH
96H 16/0600Z 17.4N 144.0W 45 KT 50 MPH
120H 17/0600Z 15.6N 148.1W 45 KT 50 MPH

$$
Forecaster Pierce/Gibbs


Source: Tropical Storm Norbert Forecast Discussion Number 11