[Yesterday 10:20 PM] Michael Webb
ISR Situation Update 2200 Hrs Friday August 21st
Tropical storm Marco discussion number 7 NWS National Hurricane Center Miami FL al142020 1100 pm EDT FRI Aug 21 2020
An Air Force Reserve Hurricane Hunter aircraft has investigated the system over the northwest Caribbean during the past few hours. The plane reported a number of unflagged SFMR winds between 35 and 40 kt and max flight level winds of 41 kt and therefore, this system has been designated as tropical storm Marco.
Once Marco moves over the central gulf of Mexico, a rapid increase in wind shear associated with an upper-level trough should limit the potential for further strengthening, and weakening is still anticipated before Marco nears the northern gulf coast, as shown in the previous official forecast.
Confidence in the track forecast is also lower than normal. Marco is currently forecast to move northwestward for the next day or two, before the ridge builds and turns the tropical cyclone farther west. Near the end of the period, Marco's track and intensity could be also influenced by tropical storm Laura.
Given the high uncertainty in the forecast, larger than normal changes could be required to future advisories.
1. Marco is forecast to strengthen over the northwestern Caribbean Sea through Saturday as it approaches the northeast coast of the Yucatan peninsula. A hurricane watch and a tropical storm warning are in effect for portions of that region.
2. The system is expected to move into the south-central Gulf of Mexico as a tropical storm on Sunday. Although some strengthening is anticipated on Sunday, weakening is forecast as the system approaches the northwestern gulf coast on Tuesday.
It is still too soon to know exactly the location and magnitude of impacts the system will produce along the central or northwestern gulf coast, and interests in that area should continue monitoring the progress of this system over the next few days.