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Hurricane Iota Forecast Discussion Number 12
2020-11-16 09:55:35| National Hurricane Center (Atlantic)
Issued at 400 AM EST Mon Nov 16 2020 000 WTNT41 KNHC 160855 TCDAT1 Hurricane Iota Discussion Number 12 NWS National Hurricane Center Miami FL AL312020 400 AM EST Mon Nov 16 2020 Iota has explosively deepened 26 mb during the past 6 hours and has rapidly intensified an incredible 35 kt during that same time. An Air Force Reserve reconnaissance aircraft and aircrew that flew the arduous, 10-hour round-trip mission into Iota reported a maximum 700-mb flight-level wind speed of 134 kt and peak SFMR surface winds of 121 kt, which supports the initial intensity of 125 kt, making Iota a strong Category 4 hurricane. Furthermore, the pressure fell an amazing 10 mb from 945 mb down to 935 mb in a little over an hour between those two fixes. The crew also encountered intense lightning and hail in the southwestern quadrant, where recent remote data indicate that frequent lightning is still occurring. The aircrew reported that the eye was around 15 n mi wide, and the latest GOES-16 hi-resolution infrared satellite imagery confirms that the eye diameter, and that the eye has cleared out with continued warming eye temperatures and cooling surrounding cloud tops. Iota is moving north of due west, or 280/09 kt. A westward to west-northwestward motion is forecast until powerful Hurricane Iota makes landfall in northeastern Nicaragua later tonight. Shortly after landfall, a building ridge to the north of the hurricane is expected to nudge Iota on a more westward track through 36 hours, followed by a slower west-southwestward motion across central and southwestern Honduras until it dissipates in the 72-96 hour period. The latest model guidance remains tightly clustered. The new NHC track forecast is very similar to the previous advisory track, and lies close to a blend of the consensus track models TVCN, NOAA-HCCA, and FSSE. Iota is expected to remain in environmental conditions characterized by near-zero vertical wind shear, SSTs near 29 deg C, and a moist mid-level environment. The combination of these factors plus the relatively small radius of maximum winds (RMW) of about 10 n mi, argues for continued rapid strengthening right up until landfall occurs, and Iota could be near Category 5 strength at that time. After landfall, rapid weakening is expected over the rugged terrain of Nicaragua and Honduras. Iota is forecast to become a tropical storm by 36 hours, and degenerate into a post-tropical remnant low by 60 hours, if not sooner, which is in line with the SHIPS intensity inland decay model. The NHC official intensity forecast remains above of all of the available guidance through 24 hours, and then closely follows the Decay-SHIPS intensity model thereafter. Key Messages: 1. Iota is expected to continue to rapidly intensify and could possibly be a catastrophic category 5 hurricane when it approaches the coast of Central America tonight. Extreme winds and a life-threatening storm surge are expected along portions of the coast of northeastern Nicaragua and eastern Honduras, where a hurricane warning is in effect. 2. Hurricane conditions and storm surge impacts are likely on Providencia today. Tropical storm conditions are expected and hurricane conditions are possible on San Andres. 3. Through Thursday, heavy rainfall from Iota will likely lead to life-threatening flash flooding and river flooding across portions of Central America. Flooding and mudslides in Honduras and Nicaragua could be exacerbated by Hurricane Etas recent effects there, resulting in significant to potentially catastrophic impacts. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 13.6N 81.1W 125 KT 145 MPH 12H 16/1800Z 13.8N 82.2W 135 KT 155 MPH 24H 17/0600Z 14.1N 83.7W 120 KT 140 MPH...INLAND 36H 17/1800Z 14.3N 85.2W 55 KT 65 MPH...INLAND 48H 18/0600Z 14.3N 86.8W 35 KT 40 MPH...INLAND 60H 18/1800Z 14.1N 88.3W 20 KT 25 MPH...POST-TROP/INLAND 72H 19/0600Z 13.8N 89.7W 20 KT 25 MPH...POST-TROP/INLAND 96H 20/0600Z...DISSIPATED $$ Forecaster Stewart
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