of 5 PM EST today, the center of Hurricane Matthew was located about
25 miles to the south of Freeport Island, Bahamas. The storm was
tracking off to the north-northwest, making steady progress toward
Florida and a large section of the U.S. coastline. Since yesterday,
maximum sustained winds have increased from around 120 mph to a
present peak wind speed of around 140 mph. More importantly, the
storm’s minimum central pressure is falling. As of the 5 PM
storm’s lowest pressure reading stood at 936 millibars —
about 2 mb stronger than Hurricane Sandy’s peak intensity.
very robust Hurricane Matthew is starting to look more and more like
a CAT 5 than a CAT 4 in the most recent satellite shots. That’s bad
news for the southeastern U.S. coastline as this powerful storm is
approaching at an oblique angle — one that, if the storm continues
along its forecast track, will push a large surge of water topped
with powerful breaking waves into numerous coastal communities. Image
National Hurricane Center.)
National Hurricane Center notes that Matthew may have just gone
through an eye-wall replacement cycle, which would result in a brief
drop in maximum sustained winds. But pressures continued to drop as
the storm got better organized, and now, the satellite picture shows
the fearful symmetry of an extremely dangerous storm. As Matthew
continues to get more organized, peak wind speeds could continue to
rise, hitting 145 mph or higher before ramping wind shear and a long
encounter with the U.S. mainland begins to check Matthew’s
Flooding Rains Threaten Lake Okeechobee Dikes
Matthew approached the coastline this afternoon, large bands of rain
began to cover much of Florida even as onshore winds stiffened. Lake
Okeechobee — which is now going through a series of dike upgrades
to protect communities east of the lake from storm events like
Matthew — is starting to see the effects of these heavy rain bands.
With 4 to 8 inches or more of rainfall possible over the Lake
Okeechobee region from Matthew (and up to 12 inches or more for parts
of coastal Florida), pressure to a dike system needing refurbishment
is likely to present serious challenges.
considerable rain bands are already blanketing Florida and 4 to 12
inches are possible for parts of the state. Image source: The
National Weather Service.)
Major Hazard Comes From a Potentially Massive Storm Surge
north and east, the main story is that Matthew is pushing a
Sandy-like storm surge toward a 430-mile section of the U.S.
to the National Hurricane Center, a
region stretching from Sebastian Inlet in Florida north to Edisto
Beach in southeastern South Carolina could experience storm surges in
the range of 7 to 11 feet. A 700-mile arc from Deerfield Beach,
Florida to the Santee River in South Carolina could see surges above
a powerful storm surge over so large an area would swamp numerous
coastal communities already facing the difficulties of human-forced
sea level rise, like increasing cases of nuisance flooding at times
of monthly and seasonal high tides. As with Sandy, Matthew’s storm
surge will rush in upon this higher launching pad resulting from
thermal expansion of the world’s waters, glacial melt, and ocean
current shifts related to climate change.
a result of Matthew’s continued strengthening over near record-hot
waters and a moisture-laden atmosphere, prospects for coastal
communities along the storm’s path don’t look very good. A 7-
to-11 foot surge is enough to swamp many communities. As we can see
in the image above, worst-case potential flooding (1 in 10
probability to exceed) for St. Augustine now puts that city under 3
to 10 feet of water — dramatically worse than last night’s
initial storm-surge model estimates of a
possible 1-to-9 foot inundation for the city.
Matthew’s expected track runs parallel to the coastline, city after
city, from Cape Canaveral to Jacksonville to Savannah to Charleston,
faces the potential for similarly extreme coastal flooding as Matthew
continues to rush shoreward.
This is an increasingly dangerous developing weather situation.
Coastal interests from the Bahamas through Florida, Georgia and the
Carolinas should stay abreast of forecasts provided by the National
Hurricane Center, stay
tuned to local weather statements, and remain to respond to possible
evacuation/emergency storm shelter information.