intensity for six hours before beginning to decay as a result of the eyewall replacement cycle. The cyclone continued to track northward under the influence of the upper-level low. The hurricane weakened to a minimal Category 4 hurricane by 00:00 UTC on October 3. By that time, Walaka's eye had degraded on satellite imagery; the eye had become cloud-filled, and the clouds making up the eyewall and central dense overcast had warmed. Walaka passed about 45 mi (75 km) west of Johnston Island around 03:00 UTC. After completing the eyewall cycle, Walaka reintensified slightly, reaching a secondary peak of 145 mph (230 km/h) around 12:00 UTC on October 3. The cyclone's eye became increasingly delineated as the clouds comprising the eyewall cooled. Although the storm had restrengthened, increasing wind shear was thinning the northwestern eyewall. Soon after, Walaka began to weaken once more as it advanced north-northeastward. Later on October 3, the western and southwestern eyewall eroded as a result of the wind shear. At the same time, upper-level cirrus outflow was disrupted in the southwestern and northeastern portions of the storm. The already strong wind shear increased even further, peaking at 54 mph (87 km/h) around 00:00 UTC. Walaka's eye disappeared from visible satellite imagery and the southwestern portion of the low-level center became uncovered. Walaka made its closest approach to the French Frigate Shoals around 06:20 UTC on October 4. At that time, the Category 3 hurricane was located approximately 35 mi (55 km) to the west-northwest. Environmental conditions deteriorated even further on October 4 as sea surface temperatures fell below and ocean heat content decreased. This caused Walaka to rapidly weaken; the hurricane fell below major hurricane intensity around 12:00 UTC and was a minimal Category 1 hurricane by 00:00 UTC on October 5. Early on October 5, Walaka turned towards the northwest as it traced the northern boundary of the upper-level low. Convection associated with the storm continued to dissipate; the remaining thunderstorm activity was displaced northeast of the storm's low-level center. The wind shear abated later on October 5, although sea surface temperatures along the remainder of the tropical storm's track were cooler than . As a result of the decreased shear, Walaka's low-level center was temporarily recovered by convection and the weakening trend slowed as the storm continued north-northwest. By late October 5, the low-level center was completely exposed once more and the remaining