Major Hurricane Matthew Briefing
Nassau County Situation Overview
At 8 a.m. Tuesday, Category 4 Hurricane Matthew was about 950 miles South Southeast of
Fernandina Beach, FL moving north around 9 mph. Maximum sustained winds remain near
145 mph.
A building local northeaster will begin to push water into the rivers and estuaries through the
approach of the storm. Periods of heavy rain coming in off the ocean may cause street and
highway flooding in normally flood prone areas.
The official forecast is for the storm to track just offshore as a major hurricane. This will
cause, at least, hurricane force wind gusts on Amelia Island and large rivers like the Nassau
and St Marys. IMPORTANT: any further west track will increase those wind impacts.
Tides along Amelia Island may be 6 to 9 feet Above Ground Level (AGL), along the St Marys
River 7 to 10 feet and 4 to 8 feet on he Nassau River . IMPORTANT: any further west track will
increase those tide levels.
Huge destructive breakers will impact Amelia Island with 3 to 5 foot wind waves possible on
Cumberland and Nassau Sounds.
Matthew’s future forecasts should continue to be closely monitored, as any westward track
shift will increase local impacts.
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
1
Northeaster Winds
Tuesday through Thursday
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
2
Five Day Cone of Uncertainty
Based on the latest NHC forecast:
•
Matthew’s closest approach to northeast
Florida and southeast Georgia will likely be
Friday and Friday night.
•
Matthew will bring significant marine and
coastal concerns to Northeast Florida and
Southeast Georgia.
•
Based on our normal track error the storm
could track onshore HEED the advice of
Emergency Officials
IMPORTANT
Note the “S” Bend in the
track bringing the storm
closer than the NHC Track
Graphic straight Lines
suggest
NOTE: The forecast cone (shaded white area and hatched
area in the graphic) is where the center of the storm is
expected to track 2/3 of the time.
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
3
Tropical Storm Force
Wind Speed Probabilities
Tropical Storm (TS) Force Wind Probabilities:
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•
•
•
•
•
•
•
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Flagler Beach, FL: 69%
Mayport, FL: 60%
Jacksonville, FL: 54%
The Villages, FL: 53%
Gainesville, FL: 44%
Kings Bay, GA: 52%
Saint Simons Island, GA: 54%
Waycross, GA: 37%
Coastal Waters: 56-80%
Probability Trend:
•
•
•
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Increased since the last advisory.
SE Georgia Coast: 5 to 6 in 10 chance of TS force winds.
NE Florida Coast: 6 in 10 chance of TS force winds.
Adjacent Atlantic Waters (out to 60 NM): 6 to 8 in 10
chance of TS force winds.
NOTE: This graphic depicts probabilities of surface winds ≥ 39 mph out
through 120 hours (cumulative probabilities).
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
4
Hurricane Force Wind Probabilities
Although these are low, they are indicating
a chance of a high impact event.
Hurricane Force Wind Probabilities:
•
•
•
•
•
•
•
•
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Flagler Beach, FL: 14%
Mayport, FL: 9%
Jacksonville, FL: 6%
The Villages, FL: 4%
Gainesville, FL: 3%
Kings Bay, GA: 7%
Saint Simons Island, GA: 7%
Waycross, GA: 1%
Coastal Waters: 10-29%
Probability Trend:
•
•
•
Increased since the last advisory.
NE Florida Coast: 1 in 10 chance of hurricane force winds.
Adjacent Atlantic Waters (out to 60 NM): 1 to 3 in 10 chance of hurricane force winds.
NOTE: This graphic depicts probabilities of surface winds ≥ 39 mph out through 120 hours
(cumulative probabilities).
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
5
Local Impacts
High Confidence of Significant Coastal Impacts Late This
Week
Expected Coastal Impacts:
•
•
•
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Building, rough surf.
Dangerous, frequent rip currents.
Significant beach erosion.
Tropical Storm Conditions possibly beginning
Thursday night for northeast Florida coastal
areas and late Thursday night or Friday
morning for southeast Georgia coastal areas.
Marine Impacts:
•
•
Building seas and increasing winds beginning
today (not totally due to the hurricane).
Tropical Storm Conditions possible Thursday
evening through Saturday.
Potential Local Impacts if the track shifts
farther west (left) of current track:
•
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Coastal flooding and heavy rainfall.
Damaging winds.
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
6
Cat 3 intensity
Paralleling Storm Inundation
Northward Track, High Tide, 15 mph
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
7
Matthew Rainfall Potential
(Does Not include Northeaster Rains)
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
8
Major Hurricane Matthew
Talking Points
A developing northeaster will cause heavy rains and local street
flooding through Thursday. Tides will gradually increase with each
tide cycle before the storm.
Based on the current track tides On Amelia Island could be 6 to 9 feet
Above Ground Level (AGL).
Nassau River possible tides 4 to 8 feet AGL. Any shift in the track
farther west will increase local tidal impacts.
Rainfall near 4 to 5 inches with the storm but possibly higher
between Tuesday and Thursday due to the northeaster.
Any shift in the track farther west will increase local impacts.
HEED the advice of local officials and Emergency Management.
The storm does not pose an IMMEDIATE threat to the region but could within 4 to 5 days. Local residents and interests should
closely monitor the future progress of the storm. Please be cautious about rumors and social media posts.
@NWSJacksonville
Weather.gov/JAX
US National Weather Service Jacksonville
9