How much of the storm will Florida get? Let’s look at the math


Tropical storm condition probabilities through week’s end. (Credit: NHC)

MONDAY UPDATE: Hurricane Matthew has established its predicted northern track along longitude 75 degrees west, but still moving at a relatively slow 6 mph. Winds had diminished to 130 mph, which was still a minimal Category 4 storm.

Matthew is forecast to slam western Haiti and Eastern Cuba as a major hurricane early Tuesday morning. The problem for Florida is a projected turn toward the northwest once it gets into the Bahamas, but the turn shouldn’t be sharp enough to bring Matthew to the coast, according to the National Hurricane Center said.

However, Monday’s cone of error was nudged west and runs up Florida’s East Coast from around Palm Beach northward all the way to Jacksonville. Tropical storm probabilities have edged up to around 30 percent in West Palm Beach.


Early Monday forecast track from the National Hurricane Center (NHC).


ORIGINAL POST: Hurricane Matthew has had a wild history with lots of twists and turns, and the plot continues to thicken.

Most forecast track models for the storm keep it east of Grand Bahama Island on Thursday.

Still, the National Weather Service offices in Miami and Melbourne are calling for possible tropical storm conditions for South Florida and East-Central Florida on Thursday as Matthew is expected to bend slightly toward the northwest. But how much of a bend is the question.

NWS Melbourne: “At a minimum, breezy/windy conditions can be expected with tropical storm conditions possible, especially over the coastal counties. Building seas/surf, dangerous rip currents at area beaches, and significant beach erosion will be possible as well. Beyond that, it remains too early to speculate on specific impacts to East-Central
Florida or their timing, as average 4 and 5 day position errors are on the order of 200 miles. It should also be noted that the forecast path of Matthew would bring the system toward the FL Peninsula at a highly oblique angle. Even a small change in position and/or track could result in a large landfall error. Residents are urged to pay close attention to the evolution of this system.”

Miami: “The greatest threat period appears to be Tuesday night and beyond. Scattered showers and thunderstorms, with even some squalls, will be possible especially along the east coast and Atlantic waters. It will likely be breezy at times as well. Threats for hazardous Atlantic marine conditions continue to increase, with significant waves, beach erosion, rip currents, and coastal flooding possible.”

Jacksonville: “The track of Matthew at this point remains highly uncertain due to a complicated setup over the eastern sea board. Ridging may try to build to the north of Matthew, which could bend the cyclone back towards the coast. The ECMWF and GFS are both in fairly good agreement on this scenario. On the other hand, the weakness to the north of Matthew may stay open due to a stronger trough east of the mid-Atlantic and northeastern conus, which is what some of the other guidance shows.”

The National Hurricane Center puts chances of tropical storm conditions — sustained winds of at least 39 mph — at around 20 percent in West Palm Beach.

Let’s do the math.

On Thursday morning, Matthew is forecast to be at 25.5N 75.5W, or 295 miles due east of Miami. On Friday morning, the projection is for 28.0N 76.2W, 270 miles due east of Melbourne.

Hurricane force winds extend 25 miles from the center, according to the NHC, and tropical storm force winds extend 205 miles. So strictly speaking, Florida’s East Coast would be out of the tropical storm area.

However, average forecast track errors at day four — Thursday — are 175 miles. Any track error to the west of around 70 miles or greater would put the peninsula’s East Coast into play for tropical storm conditions.

When you see a forecast for a north-northwest track, remember that a hurricane usually doesn’t usually follow a smooth path — it wobbles and sometimes even zig-zags.

Keep checking on developments.


Sunday morning’s Caribbean satellite shows Hurricane Matthew drifting northwest at 5 mph. (Credit: NOAA)


Author: jnelander

Freelance writer and editor

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