000 WTPZ41 KNHC 170859 TCDEP1 Hurricane Felicia Discussion Number 13 NWS National Hurricane Center Miami FL EP062021 1100 PM HST Fri Jul 16 2021 Felicia remains an impressively compact major hurricane on satellite imagery tonight. The storm possesses a circular, clear, and warm (10-15 C) eye surrounded by an equally symmetrical central dense overcast (CDO) with cloud top temperatures colder than -70 C. In addition, a 0535 UTC GMI microwave pass showed a singular closed eyewall, with only limited outer banding outside of the inner core. The 0600 UTC subjective Dvorak satellite estimates from TAFB and SAB were T6.0/115 kt and T5.5/102 kt respectively, while the UW-CIMSS ADT objective estimate was holding steady at T5.7/107 kt. Since that time, cloud top temperatures surrounding the eye have cooled a bit more during the diurnal max, so the initial intensity is held at 115 kt, in agreement with the higher TAFB estimate. The hurricane has maintained more of a west-southwest motion over the past 6-12 hours at 255/8 kt. This motion is expected to gradually bend back westward or west-northwestward over the weekend into early next week as a narrow mid-level ridge axis shifts back to the north-northeast of Felicia. In the latter part of the forecast period, a stronger deep-layer ridge north of Hawaii is expected to become the primary steering feature, leading to a Felicia turning back west-southwestward with gradual acceleration. The track guidance has shifted a tad further north early on, and has continued to speed up the forward motion near the end of the forecast period. The latest NHC track forecast has been adjusted a little more poleward in the first 60 hours, closer to the HCCA and TVCE consensus aids, and is faster after 72 hours. The forecast track still lies roughly between the previous forecast and the aforementioned track consensus aids. Felicia currently has the structural characteristics of an annular hurricane, featuring a warm eye and cold circular CDO with little additional banding beyond the eyewall. Even though sea-surface temperatures (SSTs) slowly decrease over the next 36 hours as Felicia remains embedded in a dry mid-level relative humidity environment, the modest easterly vertical wind shear (around 5-kt) forecast over the cyclone will likely prevent dry-air entrainment that could disrupt the stable eyewall structure. Thus, the intensity forecast for the first 36-48 hours remains above the majority of the guidance and it would not be surprising to see Felicia maintain its category 4 intensity longer than forecasted in the short-term. After 60 hours, the ECMWF-SHIPS guidance shows a sharp increase in northwesterly vertical winds shear as the hurricane tracks along the 26 C SST isotherm. These more unfavorable environmental conditions will likely lead to significant disruption of Felicia's tiny inner core. The weakening rate has been increased a bit more in the latter portion of the latest NHC intensity forecast, falling near the mean of the intensity guidance and HCCA consensus aid by the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 17/0900Z 14.5N 123.9W 115 KT 130 MPH 12H 17/1800Z 14.6N 125.0W 110 KT 125 MPH 24H 18/0600Z 14.9N 126.8W 105 KT 120 MPH 36H 18/1800Z 15.3N 128.7W 100 KT 115 MPH 48H 19/0600Z 15.7N 130.6W 90 KT 105 MPH 60H 19/1800Z 15.8N 132.6W 80 KT 90 MPH 72H 20/0600Z 15.6N 134.9W 65 KT 75 MPH 96H 21/0600Z 14.7N 140.0W 50 KT 60 MPH 120H 22/0600Z 13.8N 145.1W 40 KT 45 MPH $$ Forecaster Papin/Beven