ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM Hurricane Calvin Discussion Number 13 NWS National Hurricane Center Miami FL EP032023 1100 AM HST Fri Jul 14 2023 The satellite appearance of Calvin remains impressive this afternoon. Its well-defined eye is surrounded by a ring of deep, cold convective cloud tops, and visible satellite imagery shows healthy upper-level anticyclonic outflow in all quadrants of the hurricane. While some drier mid-level air appears to be wrapping around the southern and eastern portions of the circulation, Calvin's inner core still appears intact at this time. The various objective and subjective satellite estimates range from 106-115 kt, and the initial intensity is raised to 110 kt for this advisory. Some of the initial wind radii values were adjusted based on a recently processed 1402 UTC RCM-3 synthetic aperture radar overpass over Calvin. Although some small intensity fluctuations cannot be ruled out in the near term, Calvin is likely near its peak intensity. The hurricane is expected to move over cooler waters tomorrow and into a drier, more stable environment through early next week. Calvin should also encounter some increased southwesterly vertical wind shear later in the forecast period. Therefore, weakening is forecast to begin tomorrow and continue into next week. The convective structure of Calvin later in the forecast period is a source of uncertainty, with the hurricane models (HAFS-A/B) showing more of a TC-like structure while the global models (GFS and ECMWF) show it almost devoid of convection. For now, the forecast does not show Calvin becoming post-tropical until day 5. The latest intensity forecast remains on the high end of the guidance envelope through 48 h, then closely follows the multi-model consensus aids thereafter. The hurricane is moving west-northwestward at 285/14 kt. This general motion will continue for the next several days as Calvin is steered by a mid-level ridge that extends westward across the eastern subtropical Pacific. Once again, the track models are in good agreement on this scenario. The updated NHC forecast is very similar to the previous one, but just a bit slower at days 3-5 based on the latest model consensus trends. Calvin is expected to cross 140W and move into the central Pacific basin by early Monday morning, then approach the Hawaiian Islands on Tuesday and Wednesday. KEY MESSAGES: 1. Calvin is forecast to move across the central Pacific Ocean and approach the Hawaiian Islands early next week. It is too early to determine the exact location and magnitude of potential impacts given uncertainties in the track, intensity, and structure of Calvin as it approaches the islands. Interests in Hawaii should closely monitor the latest forecast updates. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 13.8N 124.6W 110 KT 125 MPH 12H 15/0600Z 14.3N 126.7W 105 KT 120 MPH 24H 15/1800Z 15.1N 129.5W 100 KT 115 MPH 36H 16/0600Z 15.7N 132.4W 90 KT 105 MPH 48H 16/1800Z 16.3N 135.5W 75 KT 85 MPH 60H 17/0600Z 16.9N 138.5W 60 KT 70 MPH 72H 17/1800Z 17.4N 141.9W 50 KT 60 MPH 96H 18/1800Z 18.3N 149.1W 40 KT 45 MPH 120H 19/1800Z 19.0N 156.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Reinhart NNNN