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Hurricane Eta Forecast Discussion Number 14
2020-11-04 03:45:26| National Hurricane Center (Atlantic)
Issued at 1000 PM EST Tue Nov 03 2020 000 WTNT44 KNHC 040245 TCDAT4 Hurricane Eta Discussion Number 14 NWS National Hurricane Center Miami FL AL292020 1000 PM EST Tue Nov 03 2020 Satellite imagery and surface observation data indicate that Hurricane Eta has moved farther inland over northeastern Nicaragua this evening. Eta has maintained a well-defined CDO feature in infrared satellite data, although passive microwave imagery is no longer depicting an eye feature. A sustained wind of 93 kt (107 mph) with a gust to 117 kt (135 mph) was reported at the Puerto Cabezas, Nicaragua, airport around 03/2139 UTC while the eye of Eta was just inland. The initial intensity of 90 kt is based on a standard decay rate for inland tropical cyclones. The initial motion estimate is 270/05 kt. The track forecast reasoning is fairly straightforward for the next 72 h. A narrow ridge to the north and northeast of the cyclone will cause Eta to gradually turn toward the west-northwest over the next 12 h, and maintain that motion through 48 h. In the 48-72 h period, Eta or its remnants are expected to turn northward and then northeastward, and emerge over the northwestern Caribbean Sea offshore the Yucatan Peninsula by 72 h. Thereafter, the forecast becomes more complex due to expected mid-latitude interaction with an upper-level trough/low currently over the southwestern U.S. that will be digging southeastward and amplifying over the Gulf of Mexico and as far south as the Yucatan by 96 h. The trough is expected to lift out Eta or its remnants northeastward across Cuba, then slow down and turn northward toward the southern Florida peninsula by 120 h when the cyclone will be interacting with an upper-level low over the southeastern Gulf of Mexico. Due to this complex mid-latitude low/trough interaction, the track forecast at days 4 and 5 contains some uncertainty. The new NHC track forecast is just a little to the left of the previous advisory track through 72 hours, but not as far west as the simple- and corrected-consensus models, and is very similar to the previous advisory track at 96 and 120 hours. Similar to the track forecast, the intensity forecast is also straightforward through 72 h, which calls for Eta to rapidly weaken for the next 48 h so using a standard decay rate for inland tropical cyclones. By 72 h and beyond, the intensity forecast becomes a little more complicated due to the aforementioned mid-latitude trough interaction. The global models are still in fairly good agreement with the development of an anticyclonically curved upper-level jetstream across the northwestern Caribbean Sea, Cuba, and the Bahamas by 96 h. There are some subtropical jet dynamics already occurring across the northwestern Caribbean, which has helped to generate widespread convection across the region today. As the jetstream amplifies ahead of the vigorous upper-level trough, significant upper-level divergence is expected to develop, which will cause surface pressures to fall across the northwestern Caribbean Sea. Those strong pressure falls will likely aid in the redevelopment of Eta or generate a new tropical cyclone. Regardless of the exact formation, the global and regional models are all in good agreement on a tropical or subtropical cyclone developing and moving across Cuba and toward Florida on days 4 and 5. The new official intensity forecast is very similar to the previous intensity forecast through 72 hours, and then is slightly higher thereafter, but not as high as some of the intensity guidance like the HCCA and ICON consensus models. Key Messages: 1. Significant wind damage is expected along the coast of northeastern Nicaragua and also inland overnight. 2. A dangerous and life-threatening storm surge, along with destructive waves, are expected along portions of the northeastern coast of Nicaragua overnight. Water levels could reach as high as 5 to 10 feet above normal tide levels in some parts of the hurricane warning area. 3. Through Friday evening, 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, El Salvador, southern Haiti, and the Cayman Islands. 4. Eta is forecast to regain tropical storm strength as 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 04/0300Z 13.8N 84.0W 90 KT 105 MPH...INLAND 12H 04/1200Z 13.9N 84.8W 60 KT 70 MPH...INLAND 24H 05/0000Z 14.4N 86.4W 35 KT 40 MPH...INLAND 36H 05/1200Z 15.3N 88.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 06/0000Z 16.0N 89.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 06/1200Z 16.9N 88.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 07/0000Z 17.9N 86.7W 35 KT 40 MPH...OVER WATER 96H 08/0000Z 21.1N 82.5W 45 KT 50 MPH 120H 09/0000Z 24.3N 80.5W 50 KT 60 MPH $$ Forecaster Stewart
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