| Track: https://www.nhc.noaa.gov/refresh/graphics_cp2+shtml/?cone#contents Satellite for Hawaii: https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G17§or=hi&band=13&length=12 NASA imagery: http://hurricanecity.com/custom-satellite/index.htm?lat=21&lon=-155&zoom=1&type=Animation&numframes=10&mapcolor=white More imagery: https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=ep082020 Hurricane Douglas Discussion Number 22 NWS Central Pacific Hurricane Center Honolulu HI EP082020 1100 AM HST Sat Jul 25 2020 The satellite presentation of Douglas is degrading somewhat, likely due to restricted outflow to the south and 26C SSTs. The U.S. Air Force 53rd Weather Reconnaissance Squadron sampled the hurricane this morning, and a blend of SFMR, flight level winds, and dropsonde data from two passes supports decreasing the intensity to 80 kt with a central pressure of 984 mb. Douglas continues to move toward the west-northwest (290 deg) at 16 kt. Douglas is being steered by a low- to mid-level ridge to the northeast and is nearing a weakness in the mid-level ridge. A continued motion toward the west-northwest and a slight decrease in forward motion will bring Douglas over or very near portions of the main Hawaiian Islands on Sunday. On Monday, a mid-level ridge is forecast to build to the north of Douglas, potentially inducing a turn toward the west, with some increase in forward speed. The updated forecast track is very close to the previous forecast and lies close to the ECMWF toward the southern end of a rather tightly clustered guidance envelope. Weakening is expected through the forecast. Douglas will remain over an area of 26C SST today, which is expected to continue the gradual weakening trend. SSTs along the forecast track increase tonight, at the same time that Douglas will move into an area of increased vertical wind shear. This is expected to maintain a weakening trend, although at a fairly slow rate. The official intensity forecast has changed very little from the previous advisory, and generally follows a blend of the corrected consensus and statistical model guidance. Based on the latest forecast, a Hurricane Warning has been issued for Oahu. Tropical Storm Warnings remain in effect for Hawaii County and Maui County. A Hurricane Watch remains in effect for Hawaii County and Maui County, and a Tropical Storm Watch is in effect for Kauai County. Key Messages: 1. Douglas continues to approach the main Hawaiian Islands, potentially passing dangerously close to, or over, the islands late tonight through Sunday night. The close passage of Douglas brings 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 vital that you do not focus on the exact forecast track or intensity of Douglas. Due to Douglas' angle of approach to the islands, any small changes 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 25/2100Z 19.5N 150.1W 80 KT 90 MPH 12H 26/0600Z 20.1N 152.1W 75 KT 85 MPH 24H 26/1800Z 21.0N 154.9W 70 KT 80 MPH 36H 27/0600Z 21.8N 157.7W 65 KT 75 MPH 48H 27/1800Z 22.5N 160.4W 60 KT 70 MPH 60H 28/0600Z 23.1N 163.5W 55 KT 65 MPH 72H 28/1800Z 23.7N 167.0W 50 KT 60 MPH 96H 29/1800Z 24.5N 173.7W 45 KT 50 MPH 120H 30/1800Z 25.8N 180.0E 35 KT 40 MPH $$ Forecaster Wroe Hurricane Douglas Intermediate Advisory Number 22A NWS Central Pacific Hurricane Center Honolulu HI EP082020 200 PM HST Sat Jul 25 2020 ...HURRICANE DOUGLAS CONTINUES TO MOVE WEST-NORTHWEST TOWARD HAWAII... SUMMARY OF 200 PM HST...0000 UTC...INFORMATION ---------------------------------------------- LOCATION...19.7N 150.7W ABOUT 280 MI...450 KM E OF HILO HAWAII ABOUT 475 MI...780 KM ESE OF HONOLULU HAWAII MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... None. SUMMARY OF WATCHES AND WARNING IN EFFECT... A Hurricane Warning is in effect for... * Oahu A Tropical Storm Warning is in effect for... * Hawaii County * Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe A Hurricane Watch is in effect for... * Hawaii County * Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe A Tropical Storm Watch is in effect for... * Kauai County, including the islands of Kauai and Niihau. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area within 36 hours. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within the next 36 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within the next 36 to 48 hours. Interests elsewhere in the main Hawaiian Islands, and in the Papahanaumokuakea Marine National Monument, should monitor the progress of this system. For storm information specific to your area, please monitor products issued by the National Weather Service office in Honolulu Hawaii. DISCUSSION AND OUTLOOK ---------------------- At 200 PM HST (0000 UTC), the eye of Hurricane Douglas was located near latitude 19.7 North, longitude 150.7 West. Douglas is moving toward the west-northwest near 16 mph (26 km/h). This motion is expected to continue through the next couple of days, with a slight decrease in forward speed today. On the forecast track, Douglas will be near the main Hawaiian Islands late tonight and is expected move over parts of the state Sunday and Monday. Maximum sustained winds are near 90 mph (150 km/h) with higher gusts. Gradual weakening is expected through the weekend. However, Douglas is still forecast to be near hurricane strength when it nears the islands. Hurricane-force winds extend outward up to 35 miles (55 km) from the center and tropical-storm-force winds extend outward up to 115 miles (185 km). The estimated minimum central pressure is 982 mb (29.00 inches). HAZARDS AFFECTING LAND ---------------------- WIND: Hurricane conditions are expected on Oahu on Sunday and Sunday night and are possible across Maui County and the Big Island late tonight and Sunday. Tropical Storm conditions are expected across Hawaii County and Maui County beginning late tonight or Sunday. Tropical Storm conditions are possible across Kauai County late Sunday. SURF: Large swells generated by Douglas are expected to affect the Hawaiian Islands during the next couple of days, and storm surge of 2 to 4 feet above normal tides is expected near the center of Douglas. The large swells and surge will produce life threatening and potentially destructive surf along exposed shores. RAINFALL: Heavy rainfall associated with Douglas is expected to affect portions of the main Hawaiian Islands from late tonight through Monday. Total rain accumulations of 5 to 10 inches are possible from Maui County westward to Kauai County, with the greatest amounts in elevated terrain. This rain may result in life-threatening flash flooding and land slides, as well as rapid water level rises on small streams. Douglas is expected to produce 2 to 5 inches of rainfall over the northern half of the Big Island. Key messages for Douglas can be found in the Tropical Cyclone Discussion under AWIPS header HFOTCDCP2 and WMO header WTPA32 PHFO. NEXT ADVISORY ------------- Next complete advisory at 500 PM HST. $$ Forecaster Wroe |