WTNT43 KNHC 132056 TCDAT3 HURRICANE GONZALO DISCUSSION NUMBER - TopicsExpress



          

WTNT43 KNHC 132056 TCDAT3 HURRICANE GONZALO DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014 500 PM AST MON OCT 13 2014 Another Air Force Reserve reconnaissance aircraft investigating Gonzalo this afternoon recently found 700-mb maximum flight-level winds of 77 kt along with believable SFMR surface winds of 62-67 kt in the northeastern quadrant, plus a central pressure of 984 mb. Based on these data, the intensity has been increased to 65 kt, making Gonzalo the sixth hurricane of the 2014 Atlantic hurricane season. Note that some higher SFMR winds were observed, but these were believed to be contaminated by shallow-water shoaling. The initial motion estimate is 305/10 kt. The center of Gonzalo has been developing northward on the Guadeloupe radar while the entire circulation has been moving west-northwestward. The result is now a northwestward motion, which is expected to continue for the next 36 hours or so. After that time, Gonzalo is forecast to gradually turn northward as a break in the subtropical to its north develops by 48-72 hours. On days 4 and 5, the hurricane is forecast to accelerate to the northeast as the southwesterly flow ahead of fast-moving deep-layer trough and associated cold front that is currently located over the south-central United States. The models are in better agreement on this track scenario with only a minor eastward shift noted through 36 hours. After that, however, the models have made a significant westward shift and now bring Gonzalo very close to Bermuda in the 96-120 hour time period. The official forecast track lies close to a blend of the GFEX and TVCN consensus models through 48 hours, and is a little to the right of the consensus models at 72-120 hours. Both the radar and satellite presentations of Gonzalo continue to improve, with a 20 n mi diameter eye noted in the radar data since about 1400-1500 UTC. Gonzalo has been strengthening at a rate of 20-25 kt since this time yesterday. Given that current environmental and oceanic conditions are expected to remain essentially unchanged for the next 48 hours, a similar rate of strengthening is forecast during that time, with Gonzalo forecast to become a major hurricane by 48 hours. After that, gradually increasing southwesterly vertical wind shear ahead of the aforementioned deep-layer trough is expected to induce gradual weakening. The NHC intensity forecast remains above the intensity consensus models, and closely follows the SHIPS intensity model. Although hurricane conditions are not currently expected in the U.S. Virgin Islands, only a slight deviation to the left of the forecast track, or a more rapid strengthening of the storm, would result in the need to extend the hurricane warning into those areas. Interests in the hurricane watch area are reminded that the watch means that hurricane conditions are possible, and in this case within the next 12-18 hours. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 17.9N 62.9W 65 KT 75 MPH 12H 14/0600Z 18.8N 64.1W 70 KT 80 MPH 24H 14/1800Z 20.5N 65.7W 80 KT 90 MPH 36H 15/0600Z 22.2N 67.1W 90 KT 105 MPH 48H 15/1800Z 23.8N 68.2W 100 KT 115 MPH 72H 16/1800Z 26.3N 68.5W 100 KT 115 MPH 96H 17/1800Z 30.0N 66.4W 95 KT 110 MPH 120H 18/1800Z 35.0N 62.8W 90 KT 105 MPH $$ Forecaster Stewart For more information, go to middletnweather.info
Posted on: Mon, 13 Oct 2014 20:57:10 +0000

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