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#904603 (Received by flhurricane at: 10:40 PM 25.Sep.2017) TCDAT4 Hurricane Lee Discussion Number 32 NWS National Hurricane Center Miami FL AL142017 1100 PM AST Mon Sep 25 2017 The satellite presentation of Lee has improved over the past 6 hours. Cloud tops have cooled and the eye has become more distinct. Dvorak intensity estimates around 0000 UTC from TAFB and the UW-CIMSS ADT were higher than the last advisory, and the intensity estimate from the ADT has gone up even more since then. The initial intensity has been increased only slightly to 80 kt, but it is possible that Lee is a little stronger than that. Lee appears to have moved out of the moderate shear zone associated with an upper-level trough, and is accelerating away from any cold water it may have previously upwelled. Further intensification in the short term seems likely, and this is supported by all of the intensity guidance. The new NHC intensity forecast is a little higher than the previous forecast, and lies between the higher dynamical models (HWRF, HMON), and the lower statistical models (SHIPS, LGEM). After about 36 hours, a sharp increase in northerly shear associated with the outflow from Maria and an approaching mid-latitude trough should cause Lee to weaken. Given the small size of Lee, it is possible that weakening could occur even faster than indicated in the official forecast. Lee has continued to move toward the west-southwest, and the initial motion estimate is 240/7 kt. There is no change to the forecast reasoning, and Lee is expected to move generally westward for the next 36 hours, along the southern edge of a mid-level ridge. After that time, a combination of Maria and the aforementioned trough should cause Lee to recurve and rapidly accelerate toward the northeast. Since Lee is moving a little faster than previously forecast, the NHC forecast has been adjusted westward for the first 36 hours of the forecast, but is generally close to the previous forecast track after that. Lee should be extratropical by no later than day 5, and some of the models indicate that it will be absorbed within a frontal boundary sooner than that. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 30.2N 51.5W 80 KT 90 MPH 12H 26/1200Z 30.2N 52.8W 85 KT 100 MPH 24H 27/0000Z 30.5N 54.6W 90 KT 105 MPH 36H 27/1200Z 31.0N 55.9W 90 KT 105 MPH 48H 28/0000Z 31.7N 56.7W 85 KT 100 MPH 72H 29/0000Z 35.3N 55.0W 70 KT 80 MPH 96H 30/0000Z 42.0N 46.0W 55 KT 65 MPH 120H 01/0000Z 49.0N 28.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Zelinsky |