ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
Hurricane Ida Advisory Number 15
NWS National Hurricane Center Miami FL AL092021
400 PM CDT Sun Aug 29 2021
...IDA MOVING NORTHWESTWARD OVER SOUTHEASTERN LOUISIANA...
...CATASTROPHIC STORM SURGE, EXTREME WINDS, AND FLASH FLOODING
CONTINUES IN PORTIONS OF SOUTHEASTERN LOUISIANA...
SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
ABOUT 45 MI...75 KM SW OF NEW ORLEANS LOUISIANA
ABOUT 70 MI...115 KM SSE OF BATON ROUGE LOUISIANA
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Hurricane Warning along the coast of Louisiana from Morgan
City to Intracoastal City has been changed to a Tropical Storm
The Tropical Storm Warning from Cameron to Intracoastal City
Louisiana has been discontinued.
The Storm Surge Warning west of Morgan City has been discontinued.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* Morgan City Louisiana to the Alabama/Florida border
* Lake Borgne, Lake Pontchartrain, Lake Maurepas, and Mobile Bay
A Hurricane Warning is in effect for...
* Morgan 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...
* Intracoastal City Louisiana to west of Morgan 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 400 PM CDT (2100 UTC), the eye of Hurricane Ida was located
near latitude 29.5 North, longitude 90.6 West. Ida is moving toward
the northwest near 10 mph (17 km/h). A turn toward the north
is expected overnight, 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
tonight. Ida is then forecast to move well inland over portions of
western Mississippi Monday and Monday night, and move across the
Tennessee Valley on Tuesday.
Doppler radar data indicate that the maximum sustained winds are
near 130 mph (215 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
and remain a tropical storm until Monday afternoon.
Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km). A Weatherflow station near Dulac just reported sustained
winds of 93 mph (150 km/h) and a gust to 135 mph (217 km/h). A
Florida Coastal Monitoring Program observing station at the South
Lafourche airport recently reported a sustained wind of 91 mph (146
km/h) and wind gust of 122 mph (196 km/h). A sustained wind of 51
mph (81 km/h) and a gust to 82 mph (131 km/h) was recently reported
at Lakefront Airport in New Orleans.
The estimated minimum central pressure is 938 mb (27.70 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
Lake Pontchartrain...5-8 ft
Ocean Springs, MS to MS/AL border...4-7 ft
Lake Maurepas...4-6 ft
MS/AL border to AL/FL border including Mobile Bay...3-5 ft
Intracoastal City, LA to Morgan City, LA including Vermilion
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 evening.
Hurricane conditions will spread farther inland within the Hurricane
Warning area over southeastern Louisiana 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, spreading northeast into the Lower
Mississippi Valley this evening 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 river
Ida is forecast to turn to the northeast on 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 flooding
along with widespread minor to isolated major riverine flooding from
the Lower Mississippi Valley into far western Alabama.
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 continue to 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 weather office.
Next intermediate advisory at 700 PM CDT.
Next complete advisory at 1000 PM CDT.