There’s an old expression about, “proximity.” It goes, “close, but no cigars.” That was clearly contrived in another era. However, in the case of Matthew, close may be close enough.
The latest National Hurricane Center’s (NHC) projected track for Matthew brings him very close to the Florida east coast near Jupiter Beach, FL by early Friday (Fig. 1). Given the size of the tropical force wind zone (sustained winds up to and including 73 miles per hour), which has been focused to within about 45 miles from the storm’s eye (with tropical storm force winds extending outward some 175 miles outward from the eye), many places in Florida will be very windy on Thursday and Friday. Locations closest to the east coast of Florida will be at the highest risk of hurricane force winds; many inland locales will experience tropical storm force winds.
As a result of Matthew’s closer approach to the east coast of Florida, hurricane and tropical storm watches and warnings have been posted for much of southern and eastern Florida (Fig. 2).
Don’t be misled by some TV meteorologists and news folks who prefer to focus on wind gusts. Wind gusts are not the measure of tropical storm or hurricane wind force conditions. They may be good for inciting excitement that the storm is stronger than it is, but…
The entire suite of hurricane dangers can be expected along the east coast of Florida. This includes high winds, torrential rains, coastal wave action, storm surge, beach erosion, local flooding and even a risk (albeit low) of tornadoes. Inland locations of south Florida, as far west as the north-south I75 corridor, can expect high winds. There will likely be a very significant rainfall gradient between coastal and inland locales, with the heaviest rainfall closer to the coast.
West coast Florida coastal areas can expect some rough surf and beach erosion.
Obviously, winds and waves over nearshore and offshore areas and Lake Okeechobee will make any water-based activities extremely dangerous.
In addition to state-declared states of emergency from Florida northward to the Carolinas, airlines have begun implementation of no-charge rebooking programs, especially for flights departing from east coast Florida airports. Note that some airlines will charge the current price of a ticket, not the price paid months ago (please read the fine print to be sure).
Florida Power and Light (FP & L), the state’s major energy supplier, has sent e-mail notices to its business customers advising them that FP &L was ready for the storm. No doubt, supermarket shelves will soon be stripped of toilet paper, milk, eggs, break and water. Hardware store will soon have no plywood for sale. And gas station lines have been reported as being long.
A safe rule, espoused by emergency management agencies, especially for hurricane warning areas, is to have a 3-day supply of water and non-refrigerated food on hand.
In some places along the southeast coast (particularly South Carolina) coastal evacuations are being ordered. This includes the state’s lane reversal evacuation plan to lessen gridlock. Under the plan, Interstate 26 will only allow traffic flow away from the coast. In other places, county evacuations are being urged, especially for low-lying coastal areas and/or sand bags are being provided by local government agencies.
As I have noted for the past several days, tropical cyclone forecast position errors grow with time. NHC has willingly shared its error values: around 175 miles at day 4 (96 hour forecast) and 230 miles at day 5 (120 hours forecast). Hence, Matthew could wind up being positioned anywhere within or near the “cone of uncertainty.”
With a storm, roughly paralleling the coast, even a slight shift is track can produce significant changes to expected weather and water conditions. One has only to think back to Hurricane Charley in 2004. For that event, a slight jog toward Florida’s west coast yielded a landfall just north of Fort Myers, rather the expected landfall 150-200 miles further north, near Tampa.
Looking well into the future, where forecast errors continue to grow, Matthew has transitioned from a New England/eastern Canada landfall to one in which the storm was expected to race across the north Atlantic toward western Europe to the current scenario in which Matthew stays roughly in place off the southeast coast and returns to the Miami area later next week. This is all the result of changes in upper level wind forecasts (because upper level winds steer hurricanes). Figures 3 through 5 showcase a few of these long-range solutions (all valid for the same time – 8:00 a.m. E.D.T. on Oct. 11, 2016).
With this long-term solution scatter in mind, it’s best to key on the first five days of the forecast. Get ready if you are in a watch or warning area and stay tuned to reliable weather updates through the period of risk.
© 2016 H. Michael Mogil
Originally posted 10/5/16