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#943901 (Received by flhurricane at: 10:53 AM 10.Oct.2018) TCDAT5 Tropical Storm Nadine Discussion Number 6 NWS National Hurricane Center Miami FL AL152018 1100 AM AST Wed Oct 10 2018 Several microwave overpasses after 0600 UTC indicated that Nadine very quickly developed a well-defined mid-level eye overnight. This signature is typically associated with strengthening tropical cyclones. Although more recent visible imagery indicates that strong shear has since caused the cyclone to become tilted with height, a pair of ASCAT passes around 1200 UTC indicated maximum winds of 45-50 kt. Given the small size of the tropical storm, the ASCAT likely under-sampled the true maximum, so the initial intensity has been raised to 55 kt. Due to limitations in our ability to observe the intensity of small tropical storms far from land, it should be noted that this estimate is fairly uncertain. Since the tropical storm appears to have become more tilted since last night, further strengthening is not likely. Shear analysis from UW-CIMSS shows that Nadine is moving into a region of 20-30 kt of westerly shear, and SHIPS diagnostics indicate that the shear could increase to near 40 kt in another couple of days. All of the intensity guidance indicates that Nadine will weaken quickly by tomorrow, and it could become a depression by 72 h. Dissipation will likely follow shortly after, as shown by nearly all of the global and regional models. The aforementioned ASCAT passes were very helpful in locating the center of Nadine at 1200 UTC, and the tropical storm is moving northwestward, or 325/6 kt. A northwestward to north-northwestward motion at a similar forward speed is anticipated for the next day or two. By Friday, a turn toward the west will likely begin as the low-level circulation of Nadine becomes separated from its convection and turns westward in the low-level easterlies. Nadine is essentially on the track of the previous NHC forecast, and no significant changes to the track forecast were required. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 12.6N 31.6W 55 KT 65 MPH 12H 11/0000Z 13.5N 32.1W 55 KT 65 MPH 24H 11/1200Z 14.6N 32.9W 50 KT 60 MPH 36H 12/0000Z 15.7N 33.9W 45 KT 50 MPH 48H 12/1200Z 16.5N 35.2W 35 KT 40 MPH 72H 13/1200Z 17.5N 39.1W 30 KT 35 MPH 96H 14/1200Z...DISSIPATED $$ Forecaster Zelinsky |