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#1151090 (Received by flhurricane at: 10:41 PM 02.Sep.2023) TCDAT4 Tropical Storm Katia Discussion Number 7 NWS National Hurricane Center Miami FL AL122023 300 AM GMT Sun Sep 03 2023 Katia has noticeably weakened since the previous advisory. Remnants of convection appear to be separating from the low-level circulation and no new bursts have formed in the past few hours. Geostationary satellite imagery suggests dry air likely has made its way into the core of the storm. Final T-numbers from TAFB and SAB were T3.0/45 and T1.5/25 . The initial intensity has therefore been lowered to 40 kt. Scatterometer data missed the center of the storm, but measured the winds on the eastern half, revealing the radii of tropical-storm-force winds had decreased. Katia is once again moving north-northwestward at about 14 kt. The storm should turn back to the northwest shortly as it moves between an upper-level low to the west and a narrow mid-latitude ridge over the eastern Atlantic. Model guidance suggests it should maintain this heading at a decreased forward speed during the next couple of days. However, the cyclone has been moving to the east of the track guidance envelope for the past several advisory cycles. Beyond day 2, there is still considerable uncertainty in the motion, and therefore location, of Katia or its remnants. The latest NHC track forecast has been shifted northward, largely due to the initial storm position. Model guidance still suggests Katia may have another burst of convection later today or Monday. Environmental conditions are expected to become increasingly unfavorable, with strong-to-moderate vertical wind shear and dry mid-level humidities. The official intensity forecast still shows gradual weakening through the forecast period and shows Katia becoming a remnant low in a couple of days, though this may occur sooner. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 26.5N 31.0W 40 KT 45 MPH 12H 03/1200Z 27.5N 32.0W 35 KT 40 MPH 24H 04/0000Z 28.3N 33.1W 30 KT 35 MPH 36H 04/1200Z 28.9N 34.1W 30 KT 35 MPH 48H 05/0000Z 29.4N 34.9W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 05/1200Z 29.8N 35.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 06/0000Z 30.2N 35.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 07/0000Z...DISSIPATED $$ Forecaster Bucci |