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Tropical Storm Eta Forecast Discussion Number 31
2020-11-08 03:57:06| National Hurricane Center (Atlantic)
Issued at 1000 PM EST Sat Nov 07 2020 000 WTNT44 KNHC 080256 TCDAT4 Tropical Storm Eta Discussion Number 31 NWS National Hurricane Center Miami FL AL292020 1000 PM EST Sat Nov 07 2020 A NOAA Hurricane Hunter aircraft found that Eta has continued to strengthen. An abbreviated mission found that the pressure had dropped to 991 mb, with believable SFMR winds of 55 kt. Since the plane left, the cloud pattern has not become better organized, and perhaps some shear is affecting the cyclone. Thus, the initial wind speed is kept at 55 kt. The storm continues to move to the northeast tonight. While the overall synoptic pattern remains the same, there has been a big change to note with the track forecast, with a notable south and west trend with almost all of the guidance on Sunday and beyond. It appears that the system becomes more involved with a closed low forming near western Cuba tomorrow, which causes a sharper and faster left turn near the Florida Straits or Keys. The new NHC forecast is shifted in that direction, but is well north of the bulk of the guidance due to continuity concerns, and future southward and faster shifts are possible. I should mention that even if the forecast does shift farther south, tropical-storm-force winds will likely cover much of the southern and central Florida peninsula due to the expected growth of Eta. Beyond Florida, this one of those times where the track uncertainty is much larger than normal, so check back tomorrow for further updates as big long-range changes are possible. Eta is likely to maintain its intensity before landfall in Cuba, then weaken somewhat due to the rugged terrain there. The storm should re-intensify over the Florida Straits in moderate shear conditions but with favorable forcing from the upper-level low. No change has been made to the intensity forecast near Florida, and Eta is likely to be near or at hurricane-strength there. Over the southeastern Gulf of Mexico, some dry air entrainment could briefly cause some weakening, but the system is forecast to move very slowly over the warm waters. In fact, a large portion of the guidance actually show it re-gaining hurricane strength as it moves farther away from any cooler shelf waters near Florida and sits over the Loop Current. While it seems pre-mature to raise the forecast much due to the large track uncertainty, the forecast is bumped up on days 3-4, but is below the model consensus. Key Messages: 1. Heavy rainfall will continue across portions of Cuba and Jamaica, and will spread north into the Bahamas and southern Florida. This rain may result in significant, life-threatening flash flooding and river flooding in Cuba. Flash and urban flooding will also be possible for Jamaica, the Bahamas and southern Florida, along with potential minor to isolated moderate river flooding in Central Florida. 2. Tropical storm conditions are expected tonight and Sunday in portions of Cuba and the northwestern Bahamas, where Tropical Storm Warnings are in effect. 3. Damaging tropical-storm-force winds are expected to begin Sunday afternoon, with hurricane-force winds possible, in the Florida Keys and portions of the southern Florida peninsula, where a Tropical Storm Warning and Hurricane Watch are in effect. Elsewhere across portions of the east and west coasts of the Florida peninsula, the risk of tropical-storm-force winds will extend well away from Eta's center, and Tropical Storm Watches and Warnings are in effect. 4. A dangerous storm surge is possible along portions of the southern coast of the Florida peninsula and the Florida Keys, where a Storm Surge Watch is in effect. Residents in the Storm Surge Watch area should follow any advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 20.7N 79.9W 55 KT 65 MPH 12H 08/1200Z 22.1N 79.3W 50 KT 60 MPH...INLAND 24H 09/0000Z 23.8N 79.8W 60 KT 70 MPH...OVER WATER 36H 09/1200Z 24.9N 81.4W 60 KT 70 MPH 48H 10/0000Z 25.0N 83.0W 55 KT 65 MPH 60H 10/1200Z 25.0N 84.0W 60 KT 70 MPH 72H 11/0000Z 25.5N 84.5W 60 KT 70 MPH 96H 12/0000Z 26.0N 84.5W 55 KT 65 MPH 120H 13/0000Z 27.0N 84.0W 45 KT 50 MPH $$ Forecaster Blake
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