Tropical Cyclone Discussion

210
WTPA44 PHFO 080233
TCDCP4
 
Tropical Storm Pena Discussion Number   6
NWS Central Pacific Hurricane Center Honolulu HI   CP042026
Issued by NWS National Hurricane Center Miami FL
500 PM HST Sat Nov 07 2026

Pena's convective structure has changed little during the past few 
hours. Satellite imagery reveals that the low-level center remains 
obscured beneath a central dense overcast (CDO), with deep 
convection displaced primarily to the northeast likely due to 
light-to-moderate southwesterly vertical wind shear. However, there 
are subtle signs of improved organization, as curved banding 
features have become more evident this cycle. A 2339 UTC AMSR3 
microwave pass captured this banding well, and the latest D-MINT 
intensity estimate based on this data was 48 kt. The latest 
subjective Dvorak intensity estimate from HFO was T3.5/55 kt, 
whereas objective estimates from UW-CIMSS range from 42 to 48 kt. 
Based on a blend of these data, the initial intensity is increased 
to 50 kt.
 
The initial motion is estimated to be westward, or 280/8 kt. Pena is 
expected to maintain a general westward track over the next couple 
of days while steered by a broad low- to mid-level ridge anchored to 
its north. Track guidance remains in excellent agreement through 60 
to 72 h. Thereafter, an approaching upper-level shortwave trough 
should induce a gradual turn toward the northwest along with a 
slight increase in forward speed, causing larger cross-track spread 
among the guidance solutions at longer forecast ranges. The updated 
NHC track forecast is virtually identical to the previous advisory 
through 60 h, then nudged slightly southward thereafter to lie 
between the prior forecast and the latest HCCA guidance.
 
The intensity forecast for Pena remains particularly challenging. 
Statistical SHIPS guidance suggests that Pena will steadily 
intensify throughout the forecast period, supported by warm SSTs and 
light vertical wind shear. However, mid-level dry air entrainment 
and marginal upper-level outflow appear to be affecting the cyclone, 
likely limiting significant intensification in the near term. This 
dilemma is reflected in the guidance, where large spread between the 
dynamical and statistical models results in lower-than-average 
forecast confidence. As a result, the new NHC intensity forecast 
closely mirrors the prior advisory, remaining near the consensus 
aids and along the upper edge of the multi-model envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0300Z 11.4N 154.5W   50 KT  60 MPH
 12H  08/1200Z 11.6N 155.8W   55 KT  65 MPH
 24H  09/0000Z 11.6N 157.6W   55 KT  65 MPH
 36H  09/1200Z 11.5N 159.6W   60 KT  70 MPH
 48H  10/0000Z 11.5N 161.7W   60 KT  70 MPH
 60H  10/1200Z 11.6N 163.8W   60 KT  70 MPH
 72H  11/0000Z 11.8N 166.2W   60 KT  70 MPH
 96H  12/0000Z 12.6N 172.1W   65 KT  75 MPH
120H  13/0000Z 14.0N 178.9W   65 KT  75 MPH