ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Tropical Storm Flossie Discussion Number 16 NWS National Hurricane Center Miami FL EP072019 1100 PM HST Wed Jul 31 2019 An ASCAT-B overpass from 0527 UTC was helpful in locating Flossie's center and diagnosing the still-asymmetric wind field. At the time, the center was located beneath very cold cloud tops of -76 degrees Celsius, but that convection has since faded away due to the result of ongoing north-northwesterly shear. Dvorak Current Intensity numbers, SATCON, and the scatterometer data all support maintaining the 55-kt initial intensity. Restrengthening of Flossie is no longer expected. For the next 3 days, mid-level shear below the outflow layer is likely to continue disrupting the vortex, and sea surface temperatures will be gradually falling by about a degree. This probably means the cyclone will continue producing bursts of deep convection that favor the eastern side of the circulation. Just about every intensity model either holds a steady intensity or shows slow weakening during the next few days, with the Florida State Superensemble the only model really showing any re-intensification (and it's only 5 kt, at that). The new NHC intensity forecast therefore holds Flossie's 55-kt intensity through 72 hours, which still ends up being higher than the model consensus. On days 4 and 5, Flossie runs into the teeth of deeper-layer westerly shear near the Hawaiian Islands, which is likely to cause weakening, if it hasn't started already. Flossie has taken on a more west-northwestward trajectory, with an initial motion of 285/14 kt. Mid-level ridging to the north of the cyclone is expected to be stationary but weaken, which should cause this heading to persist for the next 4 days with some reduction in speed. By the end of the forecast period, a deep-layer trough north of the Hawaiian Islands will influence the steering flow, causing Flossie to turn northwestward on day 5. The overall guidance envelope has shifted slightly northward, thus the new NHC track forecast is a little north of the previous forecast, most in line with the HCCA guidance and the TVCX model consensus. Although models have trended toward a track just north of the Hawaiian Islands, we want to remind users that 5-day forecast positions and intensities have average errors of about 200 miles and 20 mph, respectively. In addition, hazards associated with tropical storms extend well away from the center of circulation. Users should therefore consult local forecasts from the National Weather Service Forecast Office in Honolulu, Hawaii, at www.weather.gov/hfo for information specific to the Hawaiian Islands. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 14.7N 130.2W 55 KT 65 MPH 12H 01/1800Z 15.3N 132.5W 55 KT 65 MPH 24H 02/0600Z 16.0N 135.5W 55 KT 65 MPH 36H 02/1800Z 16.7N 138.5W 55 KT 65 MPH 48H 03/0600Z 17.4N 141.3W 55 KT 65 MPH 72H 04/0600Z 18.5N 146.3W 55 KT 65 MPH 96H 05/0600Z 19.5N 151.0W 50 KT 60 MPH 120H 06/0600Z 22.0N 155.0W 40 KT 45 MPH $$ Forecaster Berg NNNN