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Hurricane Ida Intermediate Advisory Number 14A
NWS National Hurricane Center Miami FL AL092021
100 PM CDT Sun Aug 29 2021
...EYE OF EXTREMELY DANGEROUS CATEGORY 4 HURRICANE IDA MOVING OVER
...CATASTROPHIC STORM SURGE, EXTREME WINDS, AND FLASH FLOODING IN
PORTIONS OF LOUISIANA...
SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
ABOUT 20 MI...30 KM W OF GRAND ISLE LOUISIANA
ABOUT 55 MI...90 KM SSW OF NEW ORLEANS LOUISIANA
MAXIMUM SUSTAINED WINDS...150 MPH...240 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...930 MB...27.46 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* Intracoastal City Louisiana to the Alabama/Florida border
* 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 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 Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
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 100 PM CDT (1800 UTC), the eye of Hurricane Ida was located by
NWS Doppler radar near latitude 29.2 North, longitude 90.3 West.
Ida is moving toward the northwest near 13 mph (20 km/h), and a
slightly slower northwestward motion should continue through this
evening. A turn toward the north should occur by Monday morning,
followed by a slightly faster northeastward motion by Monday night
and Tuesday. On the forecast track, the center of Ida will move
farther inland over southeastern Louisiana this afternoon and
tonight. Ida is then forecast to move well inland over portions of
Louisiana and western Mississippi Monday and Monday night, and move
across the Tennessee Valley on Tuesday.
Maximum sustained winds are near 150 mph (240 km/h) with higher
gusts. Ida is an extremely dangerous category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale. Rapid weakening is expected
during the next day or so, however Ida is forecast to remain a
hurricane through late tonight.
Hurricane-force winds extend outward up to 50 miles (85 km) from
the center and tropical-storm-force winds extend outward up to 150
miles (240 km). A Florida Coastal Monitoring Observation Tower at
South Lafourche Airport recently reported a sustained wind of
70 mph (113 km/h) and a wind gust of 102 mph (164 km/h). A
sustained wind of 47 mph (60 km/h) and a gust of 63 mph (102 km/h)
were recently reported at Lakefront Airport in New Orleans.
A NOAA National Ocean Service tide gauge in Shell Beach, Louisiana,
recently reported a water level of 6.8 feet above mean higher high
water, which is an approximation of inundation in that area.
The estimated minimum central pressure is 930 mb (27.46 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...
Port Fourchon, LA to Mouth of the Mississippi River...12-16 ft
Morgan City, LA to Port Fourchon, LA...8-12 ft
Mouth of the Mississippi River to Bay St. Louis, MS including Lake
Bay St. Louis, MS to Ocean Springs, MS...5-8 ft
Burns Point, LA to Morgan City, LA...5-8 ft
Lake Pontchartrain...5-8 ft
Ocean Springs, MS to MS/AL border...4-7 ft
Lake Maurepas...4-6 ft
East of Intracoastal City, LA to Burns Point, LA including Vermilion
MS/AL border to AL/FL border including Mobile Bay...3-5 ft
Rockefeller Wildlife Refuge, LA to Intracoastal City, LA...1-3 ft
AL/FL border to Okaloosa/Walton County Line including Pensacola
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: Catastrophic wind damage is likely near the core of Ida
as it moves inland over southeastern Louisiana through this
Hurricane conditions will spread farther inland within the Hurricane
Warning area over southeastern Louisiana through tonight. Tropical
storm conditions will also spread inland over portions of Louisiana
and Mississippi tonight and Monday.
RAINFALL: Heavy rainfall from Ida will continue to impact the
southeast Louisiana coast this morning, spreading northeast into the
Lower Mississippi Valley later today into Monday. Total rainfall
accumulations of 10 to 18 inches with isolated maximum amounts of
24 inches are possible across southeast Louisiana into far southern
Mississippi through Monday. This is likely to result in
life-threatening flash and urban flooding and significant riverine
Ida is forecast to turn to the northeast early Monday and track
across the Middle Tennessee Valley and Upper Ohio Valley through
Wednesday, producing the following rainfall totals:
Coastal Alabama to the far western Florida panhandle: 5 to 10 inches
with isolated maximum amounts of 15 inches, today through Tuesday
Central Mississippi: 4 to 8 inches with isolated maximum amounts of
12 inches, tonight through Monday night.
Middle Tennessee Valley, Upper Ohio Valley, Central Appalachians
into the Mid-Atlantic: 3 to 6 inches with isolated higher amounts,
Tuesday into Wednesday.
These rainfall totals will result in considerable flash and riverine
TORNADOES: Tornadoes will be most likely through Monday over
southeast Louisiana, southern Mississippi, southwest Alabama, and
the western Florida Panhandle. A few tornadoes are also possible
farther north across much of Mississippi and Alabama on Monday.
SURF: Swells will affect the northern Gulf coast through early
Monday. These swells are likely to cause life-threatening surf and
rip current conditions. Please consult products from your local
Next complete advisory at 400 PM CDT.