000 WTPZ41 KNHC 160859 TCDEP1 Hurricane Felicia Discussion Number 9 NWS National Hurricane Center Miami FL EP062021 200 AM PDT Fri Jul 16 2021 Tiny Felicia has continued to intensify tonight. Earlier SSMIS microwave imagery showed that the hurricane was maintaining a closed circular eyewall and cloud-top temperatures surrounding the eye on infrared satellite have continued to cool below -70 C. Scatterometer data from an ASCAT-A pass at 0418 UTC also indicated the small size of Felicia's wind field, with peak 34-kt wind radii only extending roughly 50 nm from the center in the northern semicircle. Subjective Dvorak estimates at 0600 UTC were both T5.5/102 kt from TAFB and SAB while the latest UW-CIMSS ADT objective estimate was T5.4/100 kt. A blend of these intensity estimates support a current intensity of 100 kt, making Felicia the first major hurricane in the East Pacific basin this year. Felicia now appears to be moving slightly south of due west with the latest estimated motion at 260/8 kt. Now that the strongest deep-layer ridging is positioned northwest of the hurricane, a west-southwestward motion is expected to continue for the next day or so. Afterwards, a narrow ridge axis shifts back north of Felicia, and the cyclone is expected to resume a more due westward motion between 24 to 72 hours. In the latter portion of the track forecast, the hurricane will come under the influence of a stronger mid-level ridge located north of Hawaii, resulting in another leftward turn by the end of the forecast period. The latest track guidance remains in good agreement for the majority of the forecast. The official NHC forecast is a touch south of the previous track and lies between the HCCA and TVCE consensus aids. Additional short-term intensification is forecast while Felicia remains in a favorable environment of low vertical wind shear between 5-10 kt and warm sea-surface temperatures (SSTs) between 27-28 C. Thereafter, mid-level humidity values are forecasted by the ECMWF-SHIPS guidance to drop below 50 percent as SSTs also gradually decrease. However, both deep-layer (200-850 hPa) and mid-level vertical wind shear are expected to remain light and easterly through at least the next 72 hours. Light easterly shear in combination with marginally warm SSTs are common environmental factors associated with major hurricanes that develop annular characteristics, and these storms are known to weaken at a slower than typical rate. To account for this possibility, the intensity forecast only shows very gradual weakening between 24 to 48 hours which is above the majority of the intensity guidance but lies closest to CTCI (COAMPS-TC). Afterwards, Felicia's weakening rate is forecast to increase as SSTs cool further, and northwesterly vertical-wind shear impinges on the cyclone by the end of the forecast period. The latter portion of the intensity forecast is closer to the mean of the intensity guidance and is near the HCCA intensity consensus aid at 120 hours. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 15.1N 121.0W 100 KT 115 MPH 12H 16/1800Z 14.9N 122.0W 110 KT 125 MPH 24H 17/0600Z 14.6N 123.4W 105 KT 120 MPH 36H 17/1800Z 14.5N 125.1W 100 KT 115 MPH 48H 18/0600Z 14.6N 126.8W 95 KT 110 MPH 60H 18/1800Z 14.7N 128.7W 85 KT 100 MPH 72H 19/0600Z 14.8N 130.5W 80 KT 90 MPH 96H 20/0600Z 14.6N 134.2W 65 KT 75 MPH 120H 21/0600Z 13.8N 137.6W 55 KT 65 MPH $$ Forecaster Papin/Beven