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Hurricane Douglas Forecast Discussion Number 15
2020-07-24 04:44:03| National Hurricane Center (East Pacific)
Issued at 500 PM HST Thu Jul 23 2020 000 WTPZ43 KNHC 240243 TCDEP3 Hurricane Douglas Discussion Number 15 NWS National Hurricane Center Miami FL EP082020 500 PM HST Thu Jul 23 2020 Douglas remains a well organized hurricane in visible and infrared satellite imagery. The 15-nmi-wide eye remains very distinct and the surrounding cloud tops have cooled since the previous advisory. Although not evident in conventional satellite imagery, a recent AMSR-2 microwave satellite image showed evidence of concentric eyewalls. Subjective Dvorak T-numbers from TAFB and SAB are 6.0 (115 kt) and recent UW/CIMSS ADT estimates have been creeping upward, and now also close to T6.0. Based on these estimates, the initial wind speed has been raised to 115 kt, making Douglas a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Douglas has likely reached its peak intensity as it will be moving over cooler SSTs during the next day or so. Although the predicted track of the hurricane will bring it over warmer waters when Douglas approaches the Hawaiian Islands, vertical shear is forecast to increase at that time. This is expected to result in continued gradual weakening, however Douglas is forecast to be near hurricane strength when it moves close to Hawaii. Despite the slight increase in the initial intensity, the updated NHC wind speed forecast is unchanged from the previous advisory through 36 hours, and then follows the intensity consensus guidance thereafter. Douglas continues moving quickly west-northwestward or 295/16 kt. The hurricane is forecast to remain on this heading with some slight reduction in forward speed during the next day or so as it remains to the south of a large mid-level ridge. After that time, Douglas is forecast to turn westward to the south of another strong mid-level ridge the is predicted to build well north of the Hawaiian Islands later in the weekend. The new NHC track forecast is very similar to the previous advisory and lies just south of the various consensus aids out of respect of the ECMWF and its ensemble mean which lie along the southern edge of the track envelope. Key Messages: 1. Douglas is expected to move near or over portions of the Hawaiian Islands this weekend, and there is an increasing chance that strong winds, dangerous surf, and heavy rainfall could affect portions of the state beginning Saturday night or Sunday. Interests on the Hawaiian Islands should continue to monitor the progress of Douglas and the official forecasts as they evolve over the next few days. Watches could be issued on Friday. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 14.9N 138.8W 115 KT 130 MPH 12H 24/1200Z 15.9N 141.2W 110 KT 125 MPH 24H 25/0000Z 17.1N 144.3W 100 KT 115 MPH 36H 25/1200Z 18.2N 147.4W 90 KT 105 MPH 48H 26/0000Z 19.2N 150.4W 75 KT 85 MPH 60H 26/1200Z 20.0N 153.2W 65 KT 75 MPH 72H 27/0000Z 20.5N 156.0W 60 KT 70 MPH 96H 28/0000Z 21.3N 161.8W 50 KT 60 MPH 120H 29/0000Z 21.8N 168.5W 45 KT 50 MPH $$ Forecaster Brown
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Category:Transportation and Logistics