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Hurricane BLAS Forecast Discussion Number 7
2016-07-04 16:43:43| National Hurricane Center (East Pacific)
Issued at 900 AM MDT MON JUL 04 2016 000 WTPZ43 KNHC 041443 TCDEP3 HURRICANE BLAS DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032016 900 AM MDT MON JUL 04 2016 Blas' cloud pattern consists of a large mass of cold-topped central convection and a couple of fragmented outer bands. A 1027 UTC SSM/I pass revealed a ragged mid-level eye feature, but the low-level structure appeared less organized. Dvorak satellite classifications were T4.0/65 kt and T4.5/77 kt from SAB and TAFB, respectively. Taking into account the overnight ASCAT pass, the initial intensity is set at 65 kt, the low end of the intensity estimates. The initial motion estimate is unchanged at 285/11. The track forecast remains straightforward. Blas is expected to be steered along the southern side of a deep-layer subtropical ridge extending westward from northern Mexico and the southern United States during the next 3-4 days. The cyclone should reach the western periphery of the ridge by days 4-5, which should result in a turn nearly toward the northwest. The model guidance is in relatively good agreement throughout the forecast period, though the GFS and ECMWF models diverge some after day 3. The NHC track forecast does not deviate much from the previous one and is north of the southernmost ECMWF owing to the forecast of a strong hurricane, more like the GFS solution indicates. The large-scale environment surrounding Blas is characterized by light to moderate northeasterly shear and a rich supply of moisture. Coupled with warm-enough waters, Blas should intensify into a large and intense hurricane during the next couple of days once it establishes a better organized inner core. The NHC intensity forecast continues to lean heavily on the statistical guidance, some of which strengthens Blas even more than the current forecast. Around 72 hours, even though the shear should still be low, the hurricane should enter a drier and more stable environment and begin traversing sub-26 deg C waters. This should promote a slow weakening trend that will accelerate after 96 hours once Blas moves over much cooler waters. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 13.3N 114.4W 65 KT 75 MPH 12H 05/0000Z 13.6N 116.2W 75 KT 85 MPH 24H 05/1200Z 14.1N 118.7W 90 KT 105 MPH 36H 06/0000Z 14.6N 121.2W 105 KT 120 MPH 48H 06/1200Z 15.1N 123.5W 110 KT 125 MPH 72H 07/1200Z 16.3N 127.6W 95 KT 110 MPH 96H 08/1200Z 17.8N 131.3W 75 KT 85 MPH 120H 09/1200Z 19.8N 134.7W 50 KT 60 MPH $$ Forecaster Kimberlain
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