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BULLETIN
Hurricane Marco Intermediate Advisory Number 14A
NWS National Hurricane Center Miami FL       AL142020
700 PM CDT Sun Aug 23 2020
 
...MARCO EXPECTED TO MOVE NEAR THE LOUISIANA COAST ON MONDAY...
 
 
SUMMARY OF 700 PM CDT...0000 UTC...INFORMATION
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LOCATION...26.4N 87.6W
ABOUT 180 MI...290 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...991 MB...29.27 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
None.
 
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
 
A Storm Surge Warning is in effect for....
* Morgan City Louisiana to Ocean Springs Mississippi
* Lake Borgne
 
A Hurricane Warning is in effect for...
* Morgan City Louisiana to the Mouth of the Pearl River
 
A Storm Surge Watch is in effect for...
* Sabine Pass to Morgan City Louisiana
* Ocean Springs Mississippi to the Mississippi/Alabama border
* Lake Pontchartrain and Lake Maurepas
 
A Hurricane Watch is in effect for...
* Intracoastal City to west of Morgan City
* Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans
 
A Tropical Storm Warning is in effect for...
* Mouth of the Pearl River to the Mississippi/Alabama border
* Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans
* Cameron to west of Morgan City
 
A Tropical Storm Watch is in effect for...
* Mississippi/Alabama border to the Alabama/Florida border
 
A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 36 hours in the indicated locations. For a
depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.  This is a life-threatening situation.  Persons
located within these areas should take all necessary actions to
protect life and property from rising water and the potential for
other dangerous conditions.  Promptly follow evacuation and other
instructions from local officials.
 
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued
36 hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous.  Preparations to protect life
and property should be rushed to completion.
 
A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.
 
A Hurricane Watch means that hurricane conditions are possible
within the watch area.
 
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.
 
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
 
For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 700 PM CDT (0000 UTC), the center of Hurricane Marco was located
by an Air Force Reserve Hurricane Hunter Aircraft near latitude 26.4
North, longitude 87.6 West. Marco is moving toward the
north-northwest near 13 mph (20 km/h). Marco is forecast to move
generally north-northwestward to northwestward tonight and approach
the Louisiana coast Monday afternoon. It is then forecast to turn
westward and move near or over the coast through Tuesday.
 
Maximum sustained winds are near 75 mph (120 km/h) with higher
gusts. Small fluctuations in strength are possible tonight. Gradual
weakening is expected to begin on Monday, and Marco could become a
remnant low by Tuesday night.
 
Hurricane-force winds extend outward up to 15 miles (30 km) from
the center and tropical-storm-force winds extend outward up to 105
miles (165 km).
 
The estimated minimum central pressure is 991 mb (29.27 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
STORM SURGE:  The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline.  The water could
reach the following heights above ground somewhere in the indicated
areas if the peak surge occurs at the time of high tide...
 
Morgan City LA to Mouth of the Mississippi River...4-6 ft
Mouth of the Mississippi River to Ocean Springs MS including Lake
Borgne...3-5 ft
Lake Pontchartrain and Lake Maurepas...2-4 ft
Intracoastal City LA to Morgan City LA...2-4 ft
Sabine Pass to Intracoastal City...1-3 ft
Ocean Springs MS to the AL/FL Border including Mobile Bay...1-3 ft
 
The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
dangerous waves.  Surge-related flooding depends on the relative
timing of the surge and the tidal cycle, and can vary greatly over
short distances.  For information specific to your area, please see
products issued by your local National Weather Service forecast
office.
 
WIND:  Hurricane conditions are expected within the hurricane
warning area by midday Monday, with tropical storm conditions
possible by early Monday. Tropical storm conditions are possible
within the tropical storm watch area on Monday, and hurricane
conditions are possible within the hurricane watch areas late
Monday.
 
RAINFALL:  Marco is expected to produce total rainfall accumulations
of 3 to 5 inches with isolated maximum amounts of 7 inches across
the Central U.S. Gulf coast through Tuesday.
 
This rainfall may result in scattered areas of flash and urban
flooding along the Central U.S. Gulf Coast.
 
SURF:  Swells generated by Marco are likely to affect portions of
the northern Gulf Coast for the next couple of days. These swells
are likely to cause life-threatening surf and rip current
conditions.  Please consult products from your local weather office.
 
TORNADOES:  An isolated tornado is possible early Monday morning
near the southeast Louisiana coast.  Isolated tornadoes are possible
across southeast Louisiana, southern Mississippi, southern Alabama,
and the Florida Panhandle Monday and Monday night.
 
 
NEXT ADVISORY
-------------
Next complete advisory at 1000 PM CDT.
 
$$
Forecaster Zelinsky
 
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