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| #1025328 (Received by flhurricane at: 4:03 PM 14.Nov.2020) TCDAT1 Tropical Storm Iota Discussion Number 6 NWS National Hurricane Center Miami FL AL312020 400 PM EST Sat Nov 14 2020 Deep convection has re-developed closer to the low-level center of Iota during the afternoon, and there has been an increase in banding over the southeastern portion of the circulation. Data from an Air Force Reserve reconnaissance aircraft that has flown an usually long mission from its base in Biloxi, Mississippi, indicate that the increase in organization has resulted in strengthening. The plane measured peak 925-mb flight-level winds of 55 kt, and SFMR winds of 46 kt. Those were the basis for the increase in wind speed on the 1800 UTC intermediate advisory. Given the continued increase in organization, the initial intensity has been set at 50 kt for this advisory. The aircraft reported that the minimum pressure had fallen to around 995 mb during its final pass through the center. The aircraft data indicate that Iota has not developed a tight inner core yet, but with the increase in convection closer to the center, and with the storm moving away from the coast of northwestern Colombia, it is likely Iota will begin to strengthen at a faster rate by Sunday. The upper-level wind pattern is forecast to become quite favorable while the storm traverses SSTs of around 29C. These conditions are likely to result in steady to rapid strengthening over the next couple of days and the NHC intensity forecast again predicts that Iota will be at or near major hurricane strength when it nears the coast of Central America. The SHIPS model is explicitly forecasting rapid intensification (a 30-kt increase in wind speed) over each of the next 24 h periods, and the NHC intensity forecast is quite similar, and is also in good agreement with the HFIP corrected consensus aid. Satellite imagery and the aircraft fixes show that Iota has continued to move west-southwestward today. A mid-level ridge over the Gulf of Mexico and Florida should build eastward over the western Atlantic during the next day or two. This should allow Iota to move westward to west-northwestward at a slightly faster forward speed, with this motion bringing the storm near the coast of northeastern Nicaragua or Honduras by late Monday. After landfall, a west-southwestward motion is expected to take the center of Iota inland over Central America. The track guidance has again shifted southward, partially due to the more southward initial position once again. This has resulted in another southward shift in the NHC track forecast, which is again near the TVCA multi-model consensus. The latest track forecast necessitates the issuance of a Hurricane Warning for Providencia island, and Hurricane Watches were issued earlier this afternoon for portions of the coasts of Nicaragua and Honduras. In addition to the wind and storm surge threats, Iota is likely to bring heavy rainfall and flooding to portions of Central America that are still recovering from Hurricane Eta`s impacts. Key Messages: 1. Iota is expected to intensify and be at or near major hurricane strength when it approaches the coast of Central America. There is a risk of damaging wind and a dangerous storm surge across portions of Nicaragua and Honduras beginning Monday, and a Hurricane Watch is in effect for a portion of that area. 2. Hurricane conditions are expected and storm surge impacts are possible on Providencia beginning late Sunday night. Tropical storm conditions are expected and hurricane conditions are possible by Sunday evening on San Andres. 2. Through Thursday, heavy rainfall from Iota will likely lead to life-threatening flash flooding and river flooding across portions of northern Colombia and Central America. Flooding and mudslides in Honduras and Nicaragua could be exacerbated by Hurricane Etas recent effects there, resulting in significant impacts. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 12.6N 76.5W 50 KT 60 MPH 12H 15/0600Z 12.7N 77.5W 60 KT 70 MPH 24H 15/1800Z 13.0N 78.9W 75 KT 85 MPH 36H 16/0600Z 13.4N 80.6W 90 KT 105 MPH 48H 16/1800Z 13.8N 82.2W 100 KT 115 MPH 60H 17/0600Z 14.0N 83.5W 100 KT 115 MPH...INLAND 72H 17/1800Z 14.0N 85.0W 50 KT 60 MPH...INLAND 96H 18/1800Z 13.6N 87.5W 25 KT 30 MPH...INLAND 120H 19/1800Z...DISSIPATED $$ Forecaster Brown |