490
WTPA44 PHFO 080246
TCDCP4

Hurricane Lowell Discussion Number  48
NWS Central Pacific Hurricane Center Honolulu HI   EP122026
Issued by NWS National Hurricane Center Miami FL
500 PM HST Mon Sep 07 2026

Lowell`s core structure this afternoon continues to gradually decay
as it interacts with an upper-level trough and vertical wind shear
increases. The eye is no longer observed on satellite imagery, nor
in radar data from Kauai (PHKI), or from the Air Force Reserve
Hurricane Hunters making center fixes. As Lowell interacts with the
upper-level trough, the flight-level winds on the eastern side of
the storm have increased, with the earlier recon mission finding 700
mb winds up to 131 kt. However, a dropsonde launched in the area of
maximum wind suggested that the flight level wind reduction to the
surface was much higher than usual, which makes sense because these
winds aloft occurred in an area with few convective echos from the
PHKI radar. This information provides justification to hold Lowell`s
initial intensity at 95 kt for this advisory. Another Air Force
Reserve Hurricane Hunter Mission is in the hurricane right now and
will continue to provide updated data this evening into the
overnight hours.

The hurricane`s initial motion remains north-northeastward at 025
degrees at 16 kt. Lowell`s interaction with a mid- to upper-level
trough has led to the storm accelerating to the north-northeast
today as the hurricane is steered between this feature and an
extensive deep-layer ridge to the east of the Hawaiian Islands. The
hurricane should maintain this motion with a subtle bend back left
as it makes its point of closest approach to Kauai tonight.
Ultimately the upper-level trough is forecast to weaken and or lift
out, with the mid-level ridging building build back to the northwest
of Lowell. This synoptic pattern should result in the the cyclone
turning sharply to the northwest and then west in the 36-60 h time
frame, with the NHC track following the most reliable HFIP Corrected
Consensus Approach (HCCA) and Google DeepMind (GDMI) aids. At long
range, some of the global models continue to hint at another
possible trough interaction in 96-120 h, and the NHC track forecast
shows another bend back northwest at that time. However, there
remains substantial uncertainty in both the deterministic and
ensemble track guidance by the end of the forecast period.

Lowell`s inner-core structure has been gradually decaying due to
increasing vertical wind shear, though the ongoing trough
interaction is also enhancing the flight level winds on the
hurricane`s eastern side as it accelerates. While it is possible
some baroclinic processes may help to maintain the hurricane`s wind
field tonight, high shear and decreasing sea-surface temperatures
(SSTs) should soon result in significant weakening after Lowell
passes the Hawaiian Islands. Model guidance continues to show Lowell
weakening below hurricane intensity by tomorrow afternoon, and that
is reflected in the latest NHC intensity forecast in 24-36 h.
Thereafter, more gradual weakening is expected as the shear
decreases and Lowell remains over marginally warm SSTs. Like the
track forecast, the intensity forecast in 96-120 h remains quite
uncertain, as it is unclear how Lowell`s weakened circulation will
interact with the next upper-level trough, with solutions ranging
from strengthening to dissipation. The long-range intensity forecast
remains low confidence, and the official forecast opts to remain
close to the guidance mean.

KEY MESSAGES:

1. Kauai County: The core of Lowell is forecast to pass near Niihau
tonight and early Tuesday, and damaging hurricane conditions are
expected during that time, with the highest winds atop mountains and
on windward and leeward slopes. Large damaging waves will impact
exposed portions of the coastline, producing dangerous coastal
flooding and inundation of low-lying areas through early Tuesday.

2. Periods of heavy rainfall will increase in coverage over the
Hawaiian Islands today and continue through Wednesday. This
may produce significant flash flooding and mudslides, especially
across Kauai County and portions of the Big Island.

3. Oahu: Tropical storm conditions are expected to begin tonight.
Strong, damaging wind gusts could cause tree damage and power
outages, especially in areas of higher terrain.

4. Large swells will produce life-threatening surf and rip current
conditions during the next several days across portions of the
Hawaiian Islands.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 20.3N 161.3W   95 KT 110 MPH
 12H  08/1200Z 22.7N 160.7W   85 KT 100 MPH
 24H  09/0000Z 25.3N 160.6W   60 KT  70 MPH
 36H  09/1200Z 27.2N 161.5W   50 KT  60 MPH
 48H  10/0000Z 28.2N 163.5W   45 KT  50 MPH
 60H  10/1200Z 28.2N 166.0W   45 KT  50 MPH
 72H  11/0000Z 27.9N 168.5W   40 KT  45 MPH
 96H  12/0000Z 28.0N 171.0W   40 KT  45 MPH
120H  13/0000Z 30.5N 171.5W   35 KT  40 MPH

$$
Forecaster Papin