000 WTPZ45 KNHC 100240 TCDEP5 Tropical Storm Darby Discussion Number 2 NWS National Hurricane Center Miami FL EP052022 900 PM MDT Sat Jul 09 2022 Darby is a small tropical cyclone. Conventional satellite data and passive microwave imagery indicate its inner core convection has waned a bit this evening, but it has maintained some curved convective bands around its center and signs of healthy upper-level outflow. Hopefully, scatterometer data becomes available overnight to better assess its current intensity. A blend of the subjective Dvorak estimates from SAB (T2.5/35 kt) and TAFB (T3.0/45 kt) supports an initial intensity of 40 kt for this advisory. Environmental conditions appear quite favorable for Darby to strengthen during the next couple of days or so. Deep-layer shear is expected to remain weak (less than 10 kt) as the small storm moves over SSTs of 28-28.5 degrees Celsius within a moist mid-level environment. If the inner-core structure of Darby improves overnight, there is some potential for significant intensification. In fact, the latest ECMWF SHIPS-RII guidance shows a 41 percent chance of Darby strengthening by 55 kt during the next 48 h. The official NHC intensity forecast still lies on the higher end of the guidance envelope through early next week, close to the SHIPS guidance and just slightly above the HFIP corrected consensus approach (HCCA). By 72 h, the storm is forecast to reach cooler waters and encounter a drier environment, which should induce weakening that continues through the remainder of the period. Darby continues to move quickly westward, or 280/15 kt. A deep-layer ridge centered over the southwestern United States is expected to steer Darby quickly westward over the next couple of days. Once Darby reaches a weakness in the ridge by the middle of next week, the cyclone is forecast to slow down a bit and turn toward the west-northwest on days 4-5. The official NHC track forecast is very similar to the previous one, and it remains close to the TVCE and HCCA aids. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 14.3N 114.9W 40 KT 45 MPH 12H 10/1200Z 14.4N 117.2W 45 KT 50 MPH 24H 11/0000Z 14.4N 120.1W 55 KT 65 MPH 36H 11/1200Z 14.4N 122.8W 65 KT 75 MPH 48H 12/0000Z 14.5N 125.2W 75 KT 85 MPH 60H 12/1200Z 14.8N 127.7W 80 KT 90 MPH 72H 13/0000Z 15.3N 129.9W 80 KT 90 MPH 96H 14/0000Z 16.6N 134.3W 65 KT 75 MPH 120H 15/0000Z 18.0N 139.5W 45 KT 50 MPH $$ Forecaster Reinhart/Flynn