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Hurricane Ida Intermediate Advisory Number 10A
NWS National Hurricane Center Miami FL AL092021
700 PM CDT Sat Aug 28 2021
...IDA FORECAST TO STRENGTHEN RAPIDLY BEFORE LANDFALL...
...LIFE-THREATENING STORM SURGE, POTENTIALLY CATASTROPHIC WIND
DAMAGE, AND FLOODING RAINFALL EXPECTED TO IMPACT THE NORTHERN GULF
COAST BEGINNING SUNDAY MORNING...
SUMMARY OF 700 PM CDT...0000 UTC...INFORMATION
ABOUT 200 MI...320 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 285 MI...460 KM SE OF HOUMA LOUISIANA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...969 MB...28.61 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* East of Rockefeller Wildlife Refuge Louisiana to the
* Vermilion Bay, Lake Borgne, Lake Pontchartrain, Lake Maurepas,
and Mobile Bay
A Hurricane Warning is in effect for...
* Intracoastal City Louisiana to the Mouth of the Pearl River
* Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans
A Tropical Storm Warning is in effect for...
* Cameron Louisiana to west of Intracoastal City Louisiana
* Mouth of the Pearl River 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 Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND OUTLOOK
At 700 PM CDT (0000 UTC), the eye of Hurricane Ida was located near
latitude 26.6 North, longitude 87.5 West. Ida is moving toward the
northwest near 16 mph (26 km/h), and this general motion should
continue through late Sunday or early Monday, followed by a slower
northward motion on Monday. A northeastward turn is forecast by
Monday night. On the forecast track, the center of Ida will
continue moving across the central and northern Gulf of Mexico
tonight and early Sunday, and make landfall along the coast of
Louisiana within the hurricane warning area Sunday afternoon or
evening. Ida is then forecast to move well inland over portions of
Louisiana and western Mississippi on Monday and Monday night.
Data from the NOAA Hurricane Hunter aircraft indicate that maximum
sustained winds are near 105 mph (165 km/h) with higher gusts.
Rapid strengthening is forecast during the next 12 to 24 hours and
Ida is expected to be an extremely dangerous major hurricane when it
makes landfall along the Louisiana coast on Sunday. Rapid weakening
is expected after landfall.
Hurricane-force winds extend outward up to 30 miles (45 km) from
the center and tropical-storm-force winds extend outward up to 125
miles (205 km).
The estimated minimum central pressure based on data from the
NOAA Hurricane Hunters is 969 mb (28.61 inches).
HAZARDS AFFECTING LAND
Key messages for Ida can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC,
and on the web at hurricanes.gov/graphics_at4.shtml?key_messages.
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...10-15 ft
Mouth of the Mississippi River to Ocean Springs, MS including Lake
Intracoastal City, LA to Morgan City, LA including Vermilion
Ocean Springs, MS to MS/AL border...4-7 ft
Lake Pontchartrain...5-8 ft
Lake Maurepas...4-6 ft
Pecan Island, LA to Intracoastal City, LA...3-5 ft
MS/AL border to AL/FL border including Mobile Bay...2-4 ft
Sabine Pass to Pecan Island, LA...1-3 ft
Overtopping of local levees outside of the Hurricane and Storm
Damage Risk Reduction System is possible where local inundation
values may be higher than those shown above.
The deepest water will occur along the immediate coast near and to
the east of the landfall location, 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 in the hurricane warning
area along the Louisiana coast beginning Sunday with tropical storm
conditions expected to begin by late tonight or early Sunday
morning. These conditions will spread inland over portions of
Louisiana and Mississippi Sunday night and Monday.
RAINFALL: Heavy rainfall from Ida will begin to impact the
Louisiana coast Sunday morning, spreading northeast into the Lower
Mississippi Valley later Sunday into Monday. Total rainfall
accumulations of 8 to 16 inches with isolated maximum amounts of
20 inches are possible across southeast Louisiana into southern
Mississippi through Monday. This rainfall is likely to result in
life-threatening flash and urban flooding and significant riverine
Elsewhere across eastern Louisiana, Mississippi, far southwestern
Alabama and the Middle Tennessee Valley -- considerable flash and
riverine flooding impacts are likely on Monday and Tuesday, with
rainfall totals of 4 to 8 inches possible. Rainfall from Ida will
begin to affect the Ohio Valley by mid-week, resulting in flash and
riverine flooding impacts.
Rainfall impacts from Ida will diminish across western Cuba
this evening as the storm continues to lift northward away
from the island. Additional 1 to 2 inches of rain with isolated
maximum amounts of 4 inches possible across western Cuba through
this evening. These rainfall amounts may produce flash floods and
TORNADOES: Tornadoes will be possible Sunday into Monday across
the northern Gulf coast states including parts of eastern
Louisiana, Mississippi, central and southern Alabama, and the
Florida Panhandle. The longest duration tornado threat will exist
across southeast Louisiana and southern Mississippi.
SURF: Swells are beginning to reach the northern Gulf coast and
will continue to affect that area through Monday. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
Next complete advisory at 1000 PM CDT.