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Tropical Depression Eta Forecast Discussion Number 19
2020-11-05 09:52:46| National Hurricane Center (Atlantic)
Issued at 300 AM CST Thu Nov 05 2020 000 WTNT44 KNHC 050852 TCDAT4 Tropical Depression Eta Discussion Number 19 NWS National Hurricane Center Miami FL AL292020 300 AM CST Thu Nov 05 2020 Eta has become very disorganized due to its interaction with the land mass of Central America, and may no longer have a surface circulation. Based on a few surface observations, the maximum winds are estimated to be around 25 kt over the water to the north of Honduras. Eta is likely to degenerate into a post-tropical low very soon, if it hasn't done so already. Since the low is predicted to move into the northwestern Caribbean Sea by tomorrow night, some restrengthening is forecast to begin by the weekend. However the expected broad nature of the cyclone and stronger vertical shear are likely to limit strengthening over the next several days. The official intensity forecast is similar to the latest model consensus. The center is extremely difficult to locate at this time, but based on continuity the initial motion is estimated to be 300/7 kt. Eta, or its post-tropical remnant low/trough, should continue to move over land today, and then turn northward tonight while moving along the eastern side of a broader gyre. This will take the system into the Gulf of Honduras and over the northwestern Caribbean Sea on Friday. A negatively-tilted 500-mb trough/low developing over the Gulf of Mexico should induce a generally northeastward motion for the next 2-3 days and take the cyclone across portions of Cuba in 3-4 days. Thereafter, the system is forecast to rotate cyclonically around the eastern side of the 500 mb low and turn northwestward to westward by the end of the forecast period. The official forecast is a blend of the latest GFS and ECMWF predictions, but leans toward the latter model. This track could take the system near or over portions of extreme southern Florida by late this weekend or early next week, but there is low confidence in the forecast, especially at 3-5 days. Key Messages: 1. Through Monday morning, heavy rainfall from Eta will lead to catastrophic, life-threatening flash flooding and river flooding across portions of Central America, along with landslides in areas of higher terrain. Flash and river flooding is also possible across Jamaica, southeast Mexico, the Cayman Islands and western Cuba. 2. Eta is forecast to regain tropical storm strength over the northwestern Caribbean Sea late this week. Although the details of the future track and intensity of Eta are uncertain, there is an increasing risk of impacts from wind and rainfall in portions of Cuba, southern Florida and the Florida Keys this weekend and early next week. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 14.5N 87.0W 25 KT 30 MPH 12H 05/1800Z 15.0N 87.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 24H 06/0600Z 16.2N 87.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 06/1800Z 17.4N 86.3W 35 KT 40 MPH...TROPICAL CYCLONE 48H 07/0600Z 18.5N 84.7W 40 KT 45 MPH 60H 07/1800Z 19.6N 82.9W 45 KT 50 MPH 72H 08/0600Z 21.0N 81.0W 50 KT 60 MPH 96H 09/0600Z 23.5N 79.5W 50 KT 60 MPH 120H 10/0600Z 24.5N 81.5W 55 KT 65 MPH $$ Forecaster Pasch
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