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| #1023541 (Received by flhurricane at: 10:02 AM 01.Nov.2020) TCDAT4 Tropical Storm Eta Discussion Number 4 NWS National Hurricane Center Miami FL AL292020 1000 AM EST Sun Nov 01 2020 Eta appears to be gradually becoming better organized this morning. A small area of persistent, deep convection near and over the center has supported the development of a small central dense overcast. Meanwhile, a larger convective band with limited curvature is noted well northeast and east of the storm center. Objective intensity estimates from UW-CIMSS and subjective Dvorak classifications from TAFB and SAB support an initial intensity of 35 kt. It should be noted that the center was relocated a bit farther south this morning based on overnight microwave imagery. A NOAA Hurricane Hunter aircraft is scheduled to investigate Eta this afternoon. Weak vertical wind shear and high oceanic heat content should support steady strengthening over the next couple of days. The SHIPS Rapid Intensification Index still indicates the potential for rapid strengthening, and the official NHC intensity forecast lies on the higher end of the guidance envelope. The current forecast shows Eta becoming a hurricane by 36 h, and continued strengthening is forecast through landfall. Once inland, Eta should quickly weaken over the mountainous terrain of Central America. The tropical storm is moving westward at around 13 kt. A westward or west-southwestward motion with a gradual decrease in forward speed is expected over the next several days, as Eta is steered by a mid-level ridge positioned to its north and northwest. The track guidance remains fairly tightly clustered through about 72 h, and the only change with this forecast is a slight southward correction based on the relocated center position. The official NHC forecast now brings Eta inland over Central America by 60 h. There is increased uncertainty in the track forecast post-landfall, with a range of plausible outcomes. While much of the guidance suggests Eta will spin down and weaken over Central America or possibly cross into the eastern Pacific, some model solutions indicate the potential for Eta or its remnants to re-emerge over the northwestern Caribbean Sea at or beyond day 5. For now, the official NHC forecast remains close to the previous one and the corrected consensus aid HCCA, which keeps the cyclone inland over Central America through day 5. Key Messages: 1. Eta is expected to strengthen to a hurricane before it reaches the coast of Central America early Tuesday, and there is a risk of storm surge, hurricane-force winds, and heavy rainfall for portions of Nicaragua and Honduras, where Hurricane and Tropical Storm Warnings have been issued. 2. Through Thursday afternoon, heavy rainfall from Eta may lead to life-threatening flash flooding and river flooding across portions of Jamaica, the Cayman Islands, and Central America, along with landslides in areas of higher terrain. FORECAST POSITIONS AND MAX WINDS INIT 01/1500Z 14.8N 77.2W 35 KT 40 MPH 12H 02/0000Z 14.9N 78.9W 45 KT 50 MPH 24H 02/1200Z 14.9N 80.6W 55 KT 65 MPH 36H 03/0000Z 14.5N 81.9W 65 KT 75 MPH 48H 03/1200Z 14.2N 82.7W 75 KT 85 MPH 60H 04/0000Z 13.9N 83.6W 70 KT 80 MPH...INLAND 72H 04/1200Z 13.8N 84.4W 45 KT 50 MPH...INLAND 96H 05/1200Z 14.1N 86.7W 30 KT 35 MPH...INLAND 120H 06/1200Z 14.6N 88.2W 25 KT 30 MPH...INLAND $$ Forecaster Reinhart/Brown/Berg |