000 WTPZ42 KNHC 020254 TCDEP2 Tropical Storm Fabio Discussion Number 6 NWS National Hurricane Center Miami FL EP072018 900 PM MDT Sun Jul 01 2018 During the past 18 h, Fabio's satellite appearance has gone from a curved band, to a CDO, back to a curved band, and now back to a CDO appearance, probably due to significant dry-air intrusions into the inner-core region. However, passive microwave data over the past few hours, especially a 0044Z SSMI/S overpass, indicate that the low-level center has developed closer to a region of very cold overshooting cloud tops of -88C to -90C. A closed, 30-35-nmi diameter low-level eye was evident in the SSMI/S imagery, but no mid-level eye exists due to dry air having eroded the deep convection. Having said that, the low-level eye is now embedded well within the CDO feature. The 0000 UTC satellite intensity estimate was a consensus T3.5/55 kt from TAFB, SAB, and UW-CIMSS ADT. However, the advisory is set a little higher at 60 kt based on the improved satellite appearance since the 0000Z satellite fixes. The initial motion estimate is 285/11. After a brief westward jog due to the low-level center reforming closer to the deepest convection, Fabio appears to have turned back toward the west-northwest. The cyclone is expected to continue moving west-northwestward around the southwestern periphery of a strong deep-layer ridge. The latest NHC model guidance remains tightly packed around the previous advisory track, with only a 60-nmi cross-track spread. As a result, the new forecast track is just a tad south of the previous advisory track, mainly due to the more southerly initial position, and lies close to the HCCA and FSSE consensus track models. Now that Fabio has developed a well-defined low-level eye, rapid intensification has become more likely given the favorable low shear and warm SST environment. However, the main questions are how soon, how much, and how long will the rapid strengthening be due to the presence of a pronounced mid-level dry air intrusion and the lack of a mid-level eye feature. Most of the best-performing model intensity guidance shows the greatest amount of strengthening occuring during the next 24 h, and the official forecast follows suit. After that time, possible cold upwelling beneath the cyclone becomes a factor since the cyclone will be moving over shallow warm surface waters of around 26 deg C by 48 h. As a result, the peak intensity has been capped between 36-48 h. Rapid weakening is expected afterwards due to SSTs cooling to 22 deg C by 96 h and southwesterly shear also increasing to 15-20 kt by 120 h. The official intensity forecast closely follows the HCCA and FSSE consensus models. FORECAST POSITIONS AND MAX WINDS INIT 02/0300Z 12.5N 109.5W 60 KT 70 MPH 12H 02/1200Z 13.0N 111.2W 75 KT 85 MPH 24H 03/0000Z 13.6N 113.4W 95 KT 110 MPH 36H 03/1200Z 14.5N 115.8W 110 KT 125 MPH 48H 04/0000Z 15.5N 118.3W 105 KT 120 MPH 72H 05/0000Z 17.7N 123.3W 85 KT 100 MPH 96H 06/0000Z 20.7N 128.2W 55 KT 65 MPH 120H 07/0000Z 24.0N 132.7W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Stewart