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| #1023780 (Received by flhurricane at: 9:50 AM 03.Nov.2020) TCDAT4 Hurricane Eta Discussion Number 12 NWS National Hurricane Center Miami FL AL292020 1000 AM EST Tue Nov 03 2020 Eta appears to have peaked in intensity overnight as an eyewall replacement cycle occurred early this morning. Radar data from San Andres revealed concentric eyewalls and the last images received from that radar early this morning suggests that the inner-eye wall had weakened. Around that time, the eye became cloud filled and less distinct in infrared satellite imagery. An Air Force Reserve reconnaissance aircraft that provided a couple of center fixes this morning reported that the minimum pressure has risen about 15 mb since last evening. The plane measured a peak flight-level wind of 127 kt, and a few SFMR winds slightly higher, but those winds were flagged as suspect. A dropwindsonde in the southeastern eyewall measured a surface wind of 138 kt, but the mean-layer average winds from the sonde supports a much lower intensity, and the instantaneous surface wind from that instrument is likely more representative of a wind gust. Based on the above data, the initial intensity is set at 125 kt for this advisory. Nonetheless, Eta is an extremely severe hurricane, capable of causing very high storm surges and catastrophic damage. Once the center of the hurricane moves onshore later today, rapid weakening is expected. It is still not certain if the surface circulation will survive its trek over Central America during the next several days, but the official forecast continues to show the remnants of Eta emerging over the northwestern Caribbean Sea late this week. Eta has been meandering just offshore of the coast of Nicaragua this morning, but the longer term motion is 255/4 kt. The hurricane should turn westward very soon with the center crossing the coast today. A ridge to the north of Eta should steer the cyclone on a faster westward to west-northwestward heading over northern Nicaragua and Honduras over the next couple of days. After 72 hours, a developing trough over the northern Gulf of Mexico should cause Eta or its remnants to turn northward and then northeastward. Given that the system is expected to remain over land for at least a couple of days, there continues to be significant uncertainty in the long range portion of the track and intensity forecast. Since Eta is likely to be a very slow-moving system after it makes landfall in Central America, torrential rains and inland flooding will be an extremely serious threat over the next few days. Key Messages: 1. Catastrophic wind damage is expected where Eta's eyewall moves onshore along the northeastern coast of Nicaragua. Tropical-storm- force or greater winds are already occuring within the Hurricane Warning area in Nicaragua. A Tropical Storm Warning is also in effect for the northeastern coast of Honduras. 2. A catastrophic and life-threatening storm surge, along with destructive waves, are expected along portions of the northeastern coast of Nicaragua near and to the north of where the center makes landfall. Water levels could reach as high as 14 to 21 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. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 13.6N 83.2W 125 KT 145 MPH 12H 04/0000Z 13.5N 83.8W 100 KT 115 MPH...INLAND 24H 04/1200Z 13.7N 84.9W 45 KT 50 MPH...INLAND 36H 05/0000Z 14.2N 86.5W 30 KT 35 MPH...INLAND 48H 05/1200Z 14.7N 88.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 06/0000Z 15.2N 89.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 06/1200Z 15.7N 89.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 07/1200Z 17.5N 86.5W 25 KT 30 MPH...OVER WATER 120H 08/1200Z 20.0N 82.5W 35 KT 40 MPH $$ Forecaster Brown |