ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE CELIA DISCUSSION NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016 200 PM PDT MON JUL 11 2016 During the past 6 h, the inner-core region of Celia has undergone multiple evolutions from a banding eye into a large eye that was more representative of an annular hurricane to what has now become a 20-nmi cloud-filled eye. Subjective Dvorak current intensity (CI) estimates remain T4.5/77 kt from TAFB and SAB, and CIRA and CIMSS AMSU objective intensity estimates were 87 kt and 86 kt at 1435Z, respectively. Since those subjective and objective estimates were obtained, the inner-core convection has increased markedly, especially during the past few hours, with tightly coiled convective bands now concentrated within mainly 70 nmi of the center. Based on the improved satellite appearance, the initial intensity has been increased to 85 kt. The initial motion estimate is 280/08 kt. As anticipated, Celia has slowed its forward motion as it approaches a developing weakness in the subtropical ridge. A turn toward the west-northwest later tonight is expected as Celia begins to move into the developing weakness in the ridge. The shortwave trough that is inducing this weakness is forecast to weaken in 48-72 h and lift out to the north or northeast. This will allow the ridge to re-strengthen and gradually nudge Celia back on a more westward track in the 72-120 h period. The latest NHC track guidance continues to be in excellent agreement with very little spread in the models, and the new forecast track is essentially just an update of the previous advisory track, and lies along the southern edge of the guidance envelope. The center of Celia is currently passing over 25.5 deg C SSTs based on reports from drifting buoy 43540, which is about 2 deg C cooler than the SHIPS intensity model is indicating. Having said that, the cooler water doesn't appear to have negatively affected Celia today, perhaps due to the proximity to warmer water and deeper instability to the south. However, by 12 h and beyond, Celia will be moving over a large field of sub-26 deg C SSTs and into an extensive region of stable stratocumulus clouds, and the decreasing instability is expected to induce steady weakening throughout the remainder of the forecast period. However, with the vertical shear forecast to remain low, Celia is expected to still be a tropical cyclone when it crosses 140W longitude and moves into the Central Pacific basin in 84-96 h. The new intensity forecast is similar to the previous advisory, and closely follows the consensus model IVCN. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 15.2N 126.2W 85 KT 100 MPH 12H 12/0600Z 15.7N 127.6W 85 KT 100 MPH 24H 12/1800Z 16.6N 129.4W 80 KT 90 MPH 36H 13/0600Z 17.7N 131.2W 70 KT 80 MPH 48H 13/1800Z 18.8N 133.2W 60 KT 70 MPH 72H 14/1800Z 20.5N 137.4W 50 KT 60 MPH 96H 15/1800Z 21.3N 142.0W 40 KT 45 MPH 120H 16/1800Z 21.8N 147.2W 35 KT 40 MPH $$ Forecaster Stewart NNNN