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#804903 (Received by flhurricane at: 4:46 AM 03.Oct.2015) TCDAT1 HURRICANE JOAQUIN DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112015 500 AM EDT SAT OCT 03 2015 The eye of Joaquin has been intermittently seen in infrared imagery overnight. Overall, the convective pattern is similar to what it was when the previous aircraft indicated the intensity was around 110 kt, so that will remain the intensity for this advisory. Another aircraft will be investigating Joaquin later this morning. The intensity forecast reasoning remains unchanged, with the cyclone expected to slowly weaken in the first 24 hours followed by steadier weakening due to increasing shear and cooler waters. Late in the period, Joaquin will slowly weaken as it undergoes extratropical transition. The new NHC intensity forecast is an update of the previous one and is close to the SHIPS model until extratropical transition. The initial motion is 045/11, and Joaquin should continue to accelerate northeastward today in the deep-layer southwesterly flow between a deep trough over the southeastern U.S. and the Atlantic subtropical ridge. The cross-track spread in the guidance increases on days 2 and 3 due to differences in how much Joaquin is tugged to the left by an upper-low passing to its north and northwest before the cyclone accelerates into the westerlies over the north Atlantic. The ECMWF has shifted left this cycle and is now along the left edge of the guidance, while the GFS continues to shift east with a track closer to Bermuda in 36 to 48 hours. The net change in the guidance envelope and the consensus aids is a slight shift to the east, and the official forecast has been adjusted in that direction. The NHC track now lies close to the middle of the guidance envelope. Further adjustments to the forecast track may be needed later today, and a Hurricane Watch and Tropical Storm warning continue for Bermuda. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 25.2N 73.1W 110 KT 125 MPH 12H 03/1800Z 26.7N 71.4W 105 KT 120 MPH 24H 04/0600Z 29.2N 69.2W 100 KT 115 MPH 36H 04/1800Z 31.8N 67.4W 90 KT 105 MPH 48H 05/0600Z 34.1N 66.4W 80 KT 90 MPH 72H 06/0600Z 38.0N 62.0W 70 KT 80 MPH 96H 07/0600Z 42.5N 50.0W 60 KT 70 MPH 120H 08/0600Z 47.0N 32.5W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Brennan |