ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Tropical Storm Flossie Discussion Number 9 NWS National Hurricane Center Miami FL EP072019 500 AM HST Tue Jul 30 2019 Convection associated with Flossie increased overnight, and the cyclone's cloud-top pattern has become more symmetric. However, AMSR data from about 6 hours ago indicated that most of the deep convection was limited to the southern semicircle of the cyclone, indicative of northerly shear, and an SSMIS pass at 1213 appeared to confirm that this is still the case. The latest Dvorak intensity estimates from TAFB and SAB are 55 kt and 65 kt, respectively, so the initial intensity of Flossie has been increased to 60 kt, as a compromise of those two assessments. Overall, there is little change in the track or intensity forecast reasoning. Flossie is moving westward on the south side of a broad mid-level ridge that extends across most of the eastern Pacific. All of the guidance indicates that Flossie will move generally west-northwestward for the next 5 days, and the model spread is low. Very little changes were made to the NHC track forecast which is near the various multi-model consensus aids, and confidence in the track forecast is high. Conversely, there is low confidence in the intensity forecast. Flossie appears to have about 36 to 48 hours in a marginally conducive environment to intensify, and the HWRF even explicitly forecasts that rapid intensification could occur. An increase in northerly shear in about 48 h could then inhibit further intensification, however the GFS and ECMWF suggest that the shear could decrease again by the end of the forecast period. The spread in the intensity guidance is very high, particularly beyond 48 h, with the dynamical models generally higher than the statistical guidance. No major changes were made to the intensity forecast, which is near HCCA and FSSE at all forecast hours, however larger changes could be required in future advisories given the high uncertainty in the forecast. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 12.2N 120.5W 60 KT 70 MPH 12H 31/0000Z 12.5N 122.5W 70 KT 80 MPH 24H 31/1200Z 13.1N 125.0W 85 KT 100 MPH 36H 01/0000Z 13.8N 127.6W 90 KT 105 MPH 48H 01/1200Z 14.6N 130.3W 95 KT 110 MPH 72H 02/1200Z 16.1N 136.0W 90 KT 105 MPH 96H 03/1200Z 17.3N 141.7W 90 KT 105 MPH 120H 04/1200Z 18.5N 147.0W 80 KT 90 MPH $$ Forecaster Zelinsky NNNN