000 WTNT43 KNHC 150850 TCDAT3 HURRICANE GONZALO DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014 500 AM AST WED OCT 15 2014 The small eye of Gonzalo has become a little less distinct in infrared satellite imagery overnight. It is possible that an eye wall replacement has begun, but there has been no recent microwave images to assess the current structure of the inner core. There has been little change in the subjective and objective Dvorak satellite intensity estimates overnight and the initial wind speed remains 110 kt for this advisory. Another Air Force Reserve reconnaissance aircraft is en route to the hurricane, which should provide a better assessment of the intensity of Gonzalo this morning. A UW/CIMSS shear analysis and the SHIPS model indicate that there is still some light to moderate southerly shear over the hurricane, but the shear is expected to decrease today. This favors intensification, however difficult-to-predict eye wall replacement cycles could cause some fluctuations in intensity during the next day or two. The NHC forecast calls for some slight intensification today followed by little change in strength in 24 to 48 hours. After that time, increasing southwesterly shear, drier air, and cooler sea surface temperatures should cause weakening. Gonzalo is expected to become extratropical by day 4, and the global models indicate that it will remain a powerful extratropical low through the end of the forecast period. Gonzalo is moving northwestward or 320/11 kt. The forecast track reasoning remains unchanged. The hurricane should turn north- northwestward and northward during the next day or so as it moves around the western side of a mid-level ridge over the central Atlantic. After that time, Gonzalo is forecast to turn north-northeastward and accelerate ahead of a mid-latitude trough that will be moving off the east coast of the United States. The track guidance is in excellent agreement on this scenario, however the updated NHC forecast has been shifted a little west of the previous advisory to be closer to the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 15/0900Z 22.9N 67.3W 110 KT 125 MPH 12H 15/1800Z 24.0N 68.3W 115 KT 130 MPH 24H 16/0600Z 25.5N 68.9W 115 KT 130 MPH 36H 16/1800Z 27.3N 68.5W 110 KT 125 MPH 48H 17/0600Z 29.9N 67.1W 105 KT 120 MPH 72H 18/0600Z 37.5N 62.8W 90 KT 105 MPH 96H 19/0600Z 48.5N 52.5W 70 KT 80 MPH...POST-TROP/EXTRATROP 120H 20/0600Z 54.0N 30.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown