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Hurricane Lane Forecast Discussion Number 9
2018-08-17 04:43:25| National Hurricane Center (East Pacific)
Issued at 800 PM PDT Thu Aug 16 2018 827 WTPZ44 KNHC 170243 TCDEP4 Hurricane Lane Discussion Number 9 NWS National Hurricane Center Miami FL EP142018 800 PM PDT Thu Aug 16 2018 Visible, infrared, and microwave satellite imagery indicate that Lane's overall cloud pattern has continued to improve, with several spiral bands and a more symmetrical outflow pattern having developed. Although the inner-core convection has deteriorated somewhat until just recently due to the entrainment of dry air, microwave images indicate that a well-defined inner-core and low-level eye feature has formed. Satellite intensity estimates at 0000 UTC ranged form T4.0/65 kt from TAFB and SAB to 55 kt and 59 kt from UW-CIMSS ADT and SATCON, respectively, which supported an intensity of 60 kt at that time. Since then, however, a nearly closed ring of cold-topped convection has developed near the center, so the intensity is set at 65 kt at the advisory time. Lanes has made a sharp jog toward the west-northwest during the past 6 hours, but this believed to be a short-term wobble due to the convection having recently wrapped around the north side of the low-level center. A return to a general westward motion of 280/13 kt is expected to resume shortly. The latest model guidance remains in good agreement on Lane continuing move between westward and west-northwestward direction for the next 3-4 days, followed by a turn back toward the west on day 5 as the stout subtropical ridge to the north strengthens to the east and northeast of the Hawaiian Islands and as a broad upper-level trough north of Hawaii gradually lifts out toward the northeast. The new NHC forecast track has been shifted a little to the right or north of the previous advisory track, primarily due to the more northward initial position, and closely follows the HCCA and TVCN/TVCE track consensus models. Now that a small well-defined inner core and partial eye feature have developed with a radius of maximum winds of 15-20 nmi, Lane is poised to rapidly intensity shortly, and sustain that trend for the next 36 hour so owing to the very low vertical-wind-shear and warm-SST regime that the cyclone will be moving through. Although brief intrusions of dry air may result in some flirtations in the intensity, the general trend should be for Lane to strengthen at a rate of at least 30 kt per 24 hours for the next 36-48 hours. After that, the intensity will be modulated by inner-core/eyewall fluctuations that can not be forecast accurately that far in advance. By days 4 and 5, however, a slow weakening trend is expected due to a gradual increase in southwesterly vertical wind shear. Overall, though, the new NHC intensity forecast is a little above the previous intensity forecast, and is above all of the intensity guidance. A good analog that was used for Lane's forecast was recent Hurricane Hector, which exhibited similar inner-core and outflow characteristics, and moved through similar environmental and oceanic conditions. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 11.2N 129.8W 65 KT 75 MPH 12H 17/1200Z 11.5N 131.9W 75 KT 85 MPH 24H 18/0000Z 12.0N 134.9W 90 KT 105 MPH 36H 18/1200Z 12.5N 137.7W 105 KT 120 MPH 48H 19/0000Z 13.1N 140.3W 110 KT 125 MPH 72H 20/0000Z 14.4N 145.0W 110 KT 125 MPH 96H 21/0000Z 15.2N 149.2W 105 KT 120 MPH 120H 22/0000Z 15.6N 153.7W 95 KT 110 MPH $$ Forecaster Stewart
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