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Tropical Storm Eta Forecast Discussion Number 17
2020-11-04 21:46:35| National Hurricane Center (Atlantic)
Issued at 300 PM CST Wed Nov 04 2020 000 WTNT44 KNHC 042046 TCDAT4 Tropical Storm Eta Discussion Number 17 NWS National Hurricane Center Miami FL AL292020 300 PM CST Wed Nov 04 2020 Eta continues to weaken as it moves from Nicaragua into Honduras. There is little convection left near the center, and the strongest convection remains in bands well removed from the center. As before, there are no wind observations available near the center of Eta at this time, so the initial intensity is reduced to a uncertain 35 kt. The initial motion is westward or 275/6. A mid-level ridge to the north of the cyclone should steer it on a generally west- northwestward track during the next 24 h or so. After that time, a mid- to upper-level trough moving over the central and eastern Gulf of Mexico is expected to cause Eta or is remnants to turn northward and then northeastward, Then, by 120 h, the cyclone is likely to move northward or northwestward on the eastern side of the trough as it cuts off into a closed low. The track guidance remains in reasonable agreement with this scenario, However, there remains some spread on when and where the various turns will occur, and there has also been an eastward shift in the guidance envelope after 36 h. The new forecast track is shifted to the east of the previous track after 36 h, and at 72 and 96 h it lies a little to the west of the various consensus models, Eta will continue to weaken while it crosses Honduras, and it is expected to decay to a remnant low before it reaches the Gulf of Honduras or the northwestern Caribbean Sea. Re-development is expected once the center is over the water. However, interaction with the aforementioned trough could result in a structure that is more subtropical or hybrid, as suggested by the UKMET, than a classical tropical cyclone, as suggested by the ECMWF. The new intensity forecast will follow the previous forecast and go with a gradual intensification that follows the general trend of the model guidance. However, the intensity forecast again lies a little below the intensity consensus. Although it is weakening, Eta will continue to produce heavy rainfall and flooding over portions of Central America. 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 before it moves across portions of Cuba and approaches southern Florida this weekend. While it is too soon to determine the exact timing, magnitude, and location of possible impacts from wind and rainfall, interests in Cuba, southern Florida and the Florida Keys should monitor the progress of Eta through the week. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 13.9N 85.7W 35 KT 40 MPH...INLAND 12H 05/0600Z 14.2N 86.7W 30 KT 35 MPH...INLAND 24H 05/1800Z 15.1N 87.8W 25 KT 30 MPH...POST-TROP/INLAND 36H 06/0600Z 16.5N 87.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 06/1800Z 17.7N 86.7W 30 KT 35 MPH...TROPICAL CYCLONE 60H 07/0600Z 18.8N 84.8W 40 KT 45 MPH 72H 07/1800Z 20.5N 82.6W 45 KT 50 MPH 96H 08/1800Z 24.0N 80.5W 50 KT 60 MPH 120H 09/1800Z 25.5N 82.5W 50 KT 60 MPH $$ Forecaster Beven
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