Monroe Upper Keys-Monroe Middle Keys-Monroe Lower Keys-
Including the cities of Key Largo, Marathon, and Key West
824 PM EST Wed Dec 19 2018
...STRONG COLD FRONT WILL IMPACT THE KEYS THURSDAY THROUGH
FRIDAY NIGHT...
A strong cold front is expected to blast through the Florida Keys
and adjacent coastal waters late Thursday or Thursday night. This
front is expected to bring multiple weather hazards to the Keys
from Thursday morning through Friday evening, including strong to
severe thunderstorms, strong winds on land with gales likely on
the coastal waters, and possible coastal flooding on the Gulf and
Bayside.
The main weather event is expected to occur from Thursday morning
through Friday night. The potential for strong to severe
thunderstorms ahead of the cold front will be highest from
Thursday into Thursday night. These thunderstorms may organize
into a squall line which could move through the Keys during the
late afternoon or evening hours. The primary hazards with any
thunderstorms will be strong, gusty and shifting winds along with
lightning strikes. Some of the thunderstorms on Thursday or
Thursday night could become severe with damaging winds and large
hail. Isolated waterspouts will also be possible, and there is a
slight risk for tornadoes as well. The Storm Prediction Center
continues to include all of South Florida and the Keys within a
severe thunderstorm risk area for Thursday into Thursday night.
On land, gusty south to southwest winds will increase to 20 to 30
mph on Thursday. Strong sustained west winds around 30 mph with
gusts near 40 mph are expected on Friday, with winds possibly
reaching these speeds beginning Thursday night. This will prompt a
Wind Advisory.
These persistent and strong westerly winds will cause Coastal
Flooding impacts on the Gulf and Bay side communities along the
length of the Florida Keys. The maximum water levels will likely
occur along the shores of Blackwater and Buttonwood Sounds,
around the time of high tide late Friday afternoon. In these
areas total water levels may reach 3 to 4.5 feet above mean sea
level Friday into Friday night. Coastal flood warnings and
advisories may be required.
Mariners should continue to prepare for a high impact weather
event for Thursday through Friday night, and time is running
short. Small Craft Advisories will certainly be needed during this
event beginning Thursday as strong southerly breezes develop.
Winds will become westerly and increase to near gale behind the
front Thursday night, lasting into Friday night. There is an
increasing likelihood that Gale Warnings will be needed for much
or all of the Keys coastal waters. A Gale Watch is now in effect
for all Keys coastal waters. Very large seas are also expected
with this event, peaking on Friday at 10 to 17 feet across the
Straits of Florida and deep waters of the southeastern Gulf of
Mexico, 5 to 8 feet in Hawk Channel inside the reef, and 4 to 8
feet across the Gulf waters inside five fathoms.
Listen to NOAA All Hazards Weather Radio for the latest weather
information, including possible warnings. In addition, please
remember to turn on your radio's severe weather tone activation
feature. Also visit your Florida Keys National Weather Service on
the web at www.weather.gov/keywest.
