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Tropical Storm Eta Forecast Discussion Number 5
2020-11-01 21:54:05| National Hurricane Center (Atlantic)
Issued at 400 PM EST Sun Nov 01 2020 000 WTNT44 KNHC 012053 TCDAT4 Tropical Storm Eta Discussion Number 5 NWS National Hurricane Center Miami FL AL292020 400 PM EST Sun Nov 01 2020 Eta has continued to quickly become better organized today with an increase in banding and the development of a central dense overcast feature. A NOAA Hurricane Hunter aircraft that has provided a couple of center fixes this afternoon has found a strengthening tropical storm. The aircraft has reported a minimum pressure of 992 mb and a 30 n-mi-wide eye that is open to the southwest. A blend of the SFMR and flight-level wind data support an initial wind speed of 55 kt for this advisory. Given the much improved inner-core structure as reported by the reconnaissance aircraft and the favorable environmental conditions of low vertical wind shear and high ocean heat content, additional strengthening is likely. The intensity guidance is much higher this cycle, and the various rapid intensification models show a much more significant chance of rapid strengthening over the next 24 to 36 hours. The DTOPS model indicates a 71 percent chance of a 30-kt increase in wind speed over the next 24 hours, while the SHIPS Rapid Intensification Index shows a 53 percent chance of a 45-kt increase over the next 36 hours. Based on the higher initial intensity and the more bullish guidance, the NHC intensity forecast has been increased and essentially calls for rapid strengthening until Eta reaches the coast of Central America. Once inland, Eta should quickly weaken over the mountainous terrain of Nicaragua and Honduras. Eta is still moving steadily westward or 270 degrees at about 14 kt. A westward motion at a somewhat slower forward speed is expected tonight. On Monday, Eta is forecast to turn southwestward at a slower forward speed when a mid-level ridge builds to the north and northwest of the cyclone. Eta is forecast to move inland over northeastern Nicaragua within the Hurricane Warning area Monday night or early Tuesday. The dynamical models are in relatively good agreement through about 72 hours, expect for the HWRF which shows a more northern track and keeps Eta offshore for much of the period. This solution is considered an outlier at this time, and the NHC track is in good agreement with the various global models and the HFIP corrected consensus model. Some model solutions still suggest Eta or its remnants will re-emerge over the northwestern Caribbean Sea at or beyond day 5. The new NHC 5-day position is still inland near the Gulf of Honduras close to the various consensus aids, but large uncertainty exists in the forecast at that time range due to the large spread in the track guidance. Key Messages: 1. Eta is forecast to strengthen into a hurricane tonight, and additional strengthening is forecast before it reaches the northeastern coast of Nicaragua Monday night or early Tuesday, where a Hurricane Warning is in effect. A Tropical Storm Warning is in effect for a portion of the northeastern coast of Honduras. 2. Through Friday afternoon, heavy rainfall from Eta will lead to significant, 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, Southern Haiti, and the Cayman Islands. 3. A life-threatening storm surge, along with damaging waves, is 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 10 to 15 feet above normal tide levels in some parts of the hurricane warning area. Preparations to protect life and property should be rushed to completion. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 14.9N 78.9W 55 KT 65 MPH 12H 02/0600Z 15.0N 80.5W 65 KT 75 MPH 24H 02/1800Z 14.7N 82.1W 80 KT 90 MPH 36H 03/0600Z 14.2N 83.1W 95 KT 110 MPH 48H 03/1800Z 14.0N 83.8W 75 KT 85 MPH...INLAND 60H 04/0600Z 14.0N 84.7W 50 KT 60 MPH...INLAND 72H 04/1800Z 14.1N 85.7W 35 KT 40 MPH...INLAND 96H 05/1800Z 14.7N 88.0W 25 KT 30 MPH...INLAND 120H 06/1800Z 15.5N 88.5W 25 KT 30 MPH...INLAND $$ Forecaster Brown
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