000 WTPA42 PHFO 262053 TCDCP2 Hurricane Douglas Discussion Number 26 NWS Central Pacific Hurricane Center Honolulu HI EP082020 1100 AM HST Sun Jul 26 2020 Hurricane Hunters from the Air Force 53rd Weather Reconnaissance Squadron are back out sampling Douglas. The hurricane has been resilient, with deep convection persisting to the west and north of the center under increasing vertical wind shear. The Hurricane Hunters have found that the center pressure has risen slightly, and a blend of SFMR and adjusted flight level winds supports lowering the initial intensity to 75 kt. Island-based radars are detecting the mid-level circulation of Douglas, which could be tilted slightly to the north due to the wind shear. Slow weakening is expected as Douglas passes near, or over, portions of the main Hawaiian Islands. SSTs will slowly increase along the forecast track, but southerly vertical wind shear will tilt the system and disrupt the circulation aloft, leading to gradual weakening through at least the next four days. However, Douglas is expected to remain a hurricane as it passes very near, or over, portions of the main Hawaiian Islands today and tonight. The intensity forecast was changed little from the prior advisory and is in line within a tightly clustered guidance envelope through 36 hours and near consensus thereafter. Hurricane Hunter data was essential in determining the initial motion of 290/14 kt. Douglas will continue to be steered by a low- to mid-level ridge toward the west-northwest during the next couple of days, taking the center dangerously close to the islands from Maui to Kauai through tonight, where a Hurricane Warning remains in effect. The updated forecast track was changed little from the previous forecast and remains near the southern edge of a tightly clustered guidance envelope during the next couple of days. By day three, an acceleration toward the west is expected as the increasingly shallow system is steered along the low-level trade winds. Key Messages 1. Douglas will pass dangerously close to, or over, the islands today and tonight, bringing a triple threat of hazards, including but not limited to damaging winds, flooding rainfall, and dangerously high surf, especially along east facing shores. 2. It is remains important that you do not focus on the exact forecast track of Douglas. Due to Douglas' angle of approach to the islands, any wobble in the track could lead to significant differences in where the worst weather occurs. Even if the center remains offshore, severe impacts could still be realized over the islands, as they extend well away from the center. 3. Terrain effects can cause strong localized acceleration of the wind through gaps and where winds blow downslope. These acceleration areas will shift with time as Douglas passes near the islands. Hurricane force wind gusts are possible even within the tropical storm warning area. Winds will also be stronger at the upper floors of high rise buildings. FORECAST POSITIONS AND MAX WINDS INIT 26/2100Z 21.2N 155.7W 75 KT 85 MPH 12H 27/0600Z 21.8N 158.0W 70 KT 80 MPH...NEAR OAHU 24H 27/1800Z 22.6N 161.0W 65 KT 75 MPH 36H 28/0600Z 23.1N 164.3W 55 KT 65 MPH 48H 28/1800Z 23.4N 167.7W 50 KT 60 MPH 60H 29/0600Z 23.8N 171.2W 45 KT 50 MPH 72H 29/1800Z 24.1N 175.2W 40 KT 45 MPH 96H 30/1800Z 24.4N 177.0E 35 KT 40 MPH 120H 31/1800Z 25.6N 170.0E 30 KT 35 MPH $$ Forecaster Wroe