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| #723514 (Received by flhurricane at: 4:44 PM 11.Oct.2014) TCDAT2 TROPICAL STORM FAY DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072014 500 PM AST SAT OCT 11 2014 Tropical Storm Fay remains a sheared tropical cyclone with deep convection persisting in the northwestern quadrant. A 1442 UTC ASCAT-B overpass indicated several 50-52 kt surface wind vectors in the northeastern and northwestern quadrants, and buoy 41936 measured a pressure of 990.2 mb a few hours ago when the center passed just to its west. The initial intensity is being maintained at 60 kt for this advisory given that the buoy pressure was similar to the last recon reported surface pressure, and assuming that there is some undersampling by the ASCAT instrument. An Air Force Reserve reconnaissance aircraft is scheduled to investigate the cyclone around 0000 UTC this evening. The initial motion estimate is 360/16 kt, based in large part on scatterometer and microwave satellite fixes. Fay is expected to continue moving northward around a deep-layer ridge this evening, and then turn toward the north-northeast by 0600 UTC, passing just to the southeast of Bermuda at that time. However, only a slight deviation to the west of the forecast track would bring the center and core of strongest winds very close to or even over Bermuda, and for that reason the Bermuda Weather Service has issued a hurricane watch for the island. By 24 hours, Fay is expected to get caught up in the mid-latitude westerlies and recurve rapidly to the northeast or east-northeast before it merges with a frontal system by 48 hours. The new NHC guidance has again shifted a little to the left, and the official forecast track has been shifted slightly westward through 12 hours, and closely follows the multi-model consensus TVCN. Overall, there is no significant change to the previous intensity forecast or reasoning. However, the current south-southeasterly vertical wind shear of 32 kt is forecast by the GFS-based SHIPS model to decrease to around 25 kt from the south-southwest in 12-18 hours, which could allow for some slight strengthening during the convective maximum period around 0600 UTC tonight, and it is possible that Fay could briefly reach hurricane status. After 24 hours, the wind shear is forecast to increase to more than 40 kt from the southwest, which should induce a weakening trend up until the time that Fay merges with a strong frontal system by 48 hours. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 29.5N 65.4W 60 KT 70 MPH 12H 12/0600Z 31.7N 64.4W 60 KT 70 MPH 24H 12/1800Z 33.7N 61.2W 60 KT 70 MPH 36H 13/0600Z 34.8N 56.2W 55 KT 65 MPH 48H 13/1800Z...ABSORBED BY FRONTAL SYSTEM $$ Forecaster Stewart |
