000 WTPZ42 KNHC 222101 TCDEP2 Tropical Storm Rick Discussion Number 2 NWS National Hurricane Center Miami FL EP172021 400 PM CDT Fri Oct 22 2021 A curved band of deep convection has wrapped roughly halfway around and over the estimated center of the cyclone over the past several hours, and a central dense overcast may be trying to form. Outflow has been expanding in all directions, indicative of a low-shear environment. Although there were two recent ASCAT overpasses over the cyclone, the higher magnitude vectors were likely rain inflated. Thus, the initial intensity of the system is based on the latest Dvorak intensity estimates of 35 kt from both TAFB and the UW-CIMSS ADT, making Rick the seventeenth named storm of the 2021 eastern Pacific basin hurricane season. Rick has slowed its forward motion and is now moving west-northwestward at 6 kt. A ridge to the north of the storm is forecast to weaken tonight as a deep-layer trough digs southeastward toward the western United States. Rick is expected to turn northwestward tonight then north-northwestward by Saturday night towards this weakness. The model guidance is still having a difficult time agreeing upon how abrupt of a right turn that the cyclone will make this weekend, with the GFS consistently showing a northward motion by tonight, and much of the other guidance indicating the northwest then north-northwest motion over the next few days. The NHC track forecast was nudged a little to the right of the previous one due to an overall slight shift to the right in the guidance, and lies in between the NOAA corrected consensus HCCA, and FSU Superensemble solutions. It should be noted that the model spread between the right-outlier GFS and left-outlier ECMWF models is about 175 n mi at 48 h. Therefore, the track forecast remains of low confidence. There is little change to the intensity forecast reasoning. The storm is expected to be within an ideal environment for strengthening over the next couple of days, with very little vertical wind shear, a moist airmass, and sea surface temperatures near 30 degrees C. Therefore, steady intensification is indicated by all of the model guidance through 48 h. There is some weakening indicated by the models just before the time the system would be nearing the coast of Mexico, which could be due to some dry air entraining into the cyclone's circulation. The NHC intensity remains near the IVCN consensus solution through 72 h and below HCCA. Beyond landfall, the intensity forecast is near the Decay-SHIPS prediction. The NHC intensity forecast also calls for a 24-h period of rapid intensification, which seems reasonable given the environment, the model agreement, and the SHIPS Rapid Intensification guidance that now indicates a greater than 60 percent chance of a 45-kt increase in strength over the next 36 h, and 55 kt over the next 48 h. Key Messages: 1. Rick is forecast to be a hurricane when it reaches the southwest coast of Mexico by Sunday night or Monday, and life-threatening storm surge and hurricane-force winds are possible within the Hurricane Watch area from Zihuatanejo to Punta San Telmo. There is larger-than-normal uncertainty in the track forecast of Rick, and the arrival time of hazardous conditions within the watch area could change significantly with future forecasts. Residents in this area should follow any advice given by local officials and check updates to the forecast. 2. Rick could bring tropical storm conditions to portions of the southwestern coast of Mexico as early as Sunday from east of Zihuatanejo to Tecpan de Galeana, and by Monday morning from west of Punta San Telmo to Manzanillo, where a Tropical Storm Watch is in effect. 3. Heavy rains associated with Rick are expected to move into the Mexican states of Guerrero, Michoacan, and Colima starting Saturday Night, and could persist through Monday night. This rainfall will likely produce flash flooding and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 13.1N 101.0W 35 KT 40 MPH 12H 23/0600Z 13.7N 101.4W 45 KT 50 MPH 24H 23/1800Z 14.6N 102.0W 60 KT 70 MPH 36H 24/0600Z 15.3N 102.3W 75 KT 85 MPH 48H 24/1800Z 16.1N 102.6W 80 KT 90 MPH 60H 25/0600Z 17.1N 103.0W 75 KT 85 MPH 72H 25/1800Z 18.3N 103.3W 65 KT 75 MPH...INLAND 96H 26/1800Z 23.2N 103.9W 35 KT 40 MPH...POST-TROP/INLAND 120H 27/1800Z...DISSIPATED $$ Forecaster Latto/Pasch