After hitting Haiti and Cuba Tuesday and Tuesday night, Matthew has re-emerged over warm water in a low shear environment. Its satellite presentation has shown signs of improvement Wednesday morning. In addition, NOAA and Air Force Hurricane Hunters flying through the storm have noted an increase in wind speed. Thus, the 11am advisory has maximum sustained winds at 120mph. The minimum central pressure is 962mb and the storm was moving to the NW at 12mph.
As the storm continues through the Bahamas, it is likely to restrengthen a bit further in the low shear/warm SST environment. In addition, Matthew turned to the NW early Wednesday morning as it begins to round the perimeter of the Bermuda high. It will now likely continue on this northwesterly track through Friday. The official forecast track takes Matthew through the Bahamas as a dangerous category 4 hurricane, and then parallels the Florida east coastline late Thursday and Friday. By Saturday, the forecast gets a bit more murky. Models Tuesday night and Wednesday have begun to hint at a loop in the long term track of Matthew. Instead of an impact to the Mid-Atlantic and the Northeast, the storm would stay south of the Outer Banks and turn southeastward early next week as high pressure builds in from the north. While not all models have jumped on this, it looks increasingly likely that the Carolinas would be spared a direct hit. Nonetheless, they are still well within the cone of uncertainty and should stay alert.
As previously mentioned, the models are not all in agreement with Matthew’s forecast. Not only are there a couple models that remain well offshore of Florida, but there are several that do not make the aforementioned ‘loop’ in the extended term.
The next area to see the impacts from Major Hurricane Matthew will be the Bahamas. The track of Matthew takes it directly over many of the islands during the next 24-36 hours, including the capital city of Nassau. This would bring the worst winds through some of the more heavily populated islands, as well as a potentially devastating storm surge and very heavy rain. The storm surge could be 10′-15′ in spots, with 8″-12″ of rainfall likely and isolated amounts of 15″! While the center may not move over every island, the wind field is rather large. Hurricane force winds extend outward 45 miles from the center, and tropical storm force winds extend 175 miles from the center.
After impacts with the Bahamas, Matthew will track uncomfortably close to the east coast of Florida Thursday night and Friday. The 11am Advisory continues a gradual westward nudge in the track, with the center-line now well within 50 miles of the coastline. The concern for hurricane conditions on Friday along the immediate coast has certainly grown. The track is close enough to the coast that only a slight shift west or east will have a significant effect on impacts.
With the forecasted track this close to the coast, all kinds of watches and warnings have been issued. Tropical Storm Warnings are up for the Upper Keys through Miami-Dade County, and northward along the spine of the Peninsula. Meanwhile, Hurricane Warnings have been issued for Broward County north through Volusia, with Hurricane Watches just north of that through Jacksonville.
Winds will significantly vary along Florida’s east coast on Friday depending on just how close the center of the storm comes to a direct landfall. As of now, even with a storm just offshore, many of the coastal cities from the Treasure Coast through the Space Coast are in the path of hurricane wind gusts. A snapshot of wind gust speeds Friday morning shows the potential for hurricane force gusts. The model depicted below is from the GFS. While the strongest winds would be within a few miles of the coast, tropical storm force winds will cover a much larger area. Inland counties along the spine of the Peninsula have the potential to see tropical storm force winds for some time on Friday. Gusts 30-40mph could even be possible all the way back to the west coast.
Another potential impact from Matthew will be the rainfall. While the heaviest rains may very well line up just offshore, coastal areas of Florida could easily see 4″-7″ with isolated amounts of 10″+. That heavy rain may extend northward along the coasts of Georgia and South Carolina into Saturday. The image below from NOAA shows rainfall from Wednesday morning through Saturday morning.
In addition to the rainfall and wind potentials, another impact from Matthew will be the storm surge and wave heights. The map below shows wave heights offshore easily above 18′ Friday morning. If the high tide lines up with Matthews maximum storm surge, the water could reach 3′-5′ above ground from North Palm Beach to the Flagler/Volusia County line. However, if the storm moves a bit farther west and makes landfall somewhere in Florida, these water heights will likely increase significantly.