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Tropical Storm Eta Forecast Discussion Number 36
2020-11-09 10:03:02| National Hurricane Center (Atlantic)
Issued at 400 AM EST Mon Nov 09 2020 000 WTNT44 KNHC 090902 CCA TCDAT4 Tropical Storm Eta Discussion Number 36...Corrected NWS National Hurricane Center Miami FL AL292020 400 AM EST Mon Nov 09 2020 Corrected a typo in the second paragraph Tropical Storm Eta made landfall in the middle Florida Keys around 11 pm EST with maximum winds of about 55 kt. Since then it has moved across Florida Bay and is now located off the coast of extreme southwestern Florida. The storm has generally changed little in strength overnight with maximum winds estimated to be near 55 kt based on NOAA Hurricane Hunter and Doppler radar data. Bands of heavy rain and tropical-storm-force winds continue over portions of the Florida Keys, and south and central Florida. Eta is now moving west-northwestward at 12 kt. The upper-level trough that Eta is entangled with and a mid-level high pressure system off the southeast U.S. coast should steer the storm westward to west-southwestward away from south Florida and the Keys through tonight. The steering currents surrounding Eta are expected to collapse on Tuesday, and most of the guidance responds by showing Eta meandering over the southeastern Gulf of Mexico in the 24-48 hour time period. After that time, the models diverge significantly with the ECMWF showing a turn to the north or northeast in response to an upper trough that is expected to move into the northwestern Gulf of Mexico. However, the latest runs of GFS and UKMET models show the trough lifting out and provided little steering for Eta, which causes a continued slow and erratic motion over the Gulf in those models. The new track forecast shows a slower northward to northeastward motion compared to the previous one from days 3-5 as a compromise of the latest models and continuity. Due to the poor model agreement beyond a couple of days, the track forecast at the longer range is of low confidence, and large changes are possible if the models converge toward the GFS/UKMET solutions. The storm will have an opportunity to strengthen a little during the next couple of days and it could become a hurricane as it moves over the warm waters of the Gulf of Mexico Loop current and remains in light-to-moderate wind shear conditions. However, there will be a fair amount of dry air surrounding Eta, and that should limit the amount of intensification. Beyond a couple of days, depending on exactly where Eta is, the models show an increase in westerly shear, which in combination with the dry air should cause a slow decay. The NHC intensity forecast is unchanged from the previous one, and is also of low confidence since its unclear where Eta will be located later in the week. Key Messages: 1. Heavy rainfall from Eta will continue across portions of Cuba, Jamaica, the Bahamas, and southern Florida and spread north into central Florida. Life-threatening flash flooding will be possible across inundated urban areas of southeast Florida today. Flash and urban flooding will also be possible for Cuba, Jamaica, the Bahamas and the remainder of southern Florida, along with potential minor river flooding in central Florida. 2. Tropical storm conditions will continue across portions of the Florida Keys, and south and central Florida today. 3. Water levels will gradually recede along portions of the southern coast of the Florida peninsula and Keys. Residents in these areas should follow any advice given by local officials. 4. Eta could approach the Florida Gulf Coast later this week as a tropical storm, and possibly bring impacts from rain, wind, and storm surge. Interests in this area should monitor the progress of Eta and updates to the forecast this week. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 25.2N 82.0W 55 KT 65 MPH 12H 09/1800Z 24.6N 83.7W 60 KT 70 MPH 24H 10/0600Z 23.8N 84.7W 60 KT 70 MPH 36H 10/1800Z 23.9N 85.1W 65 KT 75 MPH 48H 11/0600Z 24.8N 85.1W 65 KT 75 MPH 60H 11/1800Z 26.0N 85.0W 65 KT 75 MPH 72H 12/0600Z 26.7N 84.7W 60 KT 70 MPH 96H 13/0600Z 27.8N 84.2W 55 KT 65 MPH 120H 14/0600Z 29.4N 83.2W 45 KT 50 MPH...INLAND $$ Forecaster Cangialosi
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