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BULLETIN
Hurricane Ida Intermediate Advisory Number 16A
NWS National Hurricane Center Miami FL       AL092021
100 AM CDT Mon Aug 30 2021
 
...IDA MOVING NORTHWARD OVER SOUTHEASTERN LOUISIANA...
...DANGEROUS STORM SURGE, DAMAGING WINDS, AND FLASH FLOODING
CONTINUE OVER PORTIONS OF SOUTHEASTERN LOUISIANA...
 
 
SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...30.6N 90.8W
ABOUT 20 MI...30 KM SSW OF GREENSBURG LOUISIANA
ABOUT 45 MI...70 KM SSW OF MCCOMB MISSISSIPPI
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...N OR 355 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...972 MB...28.70 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 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 100 AM CDT (0600 UTC), the center of Hurricane Ida was located 
by NOAA Doppler weather radars and satellite data near latitude 
30.6 North, longitude 90.8 West. Ida is moving toward the north 
near 9 mph (15 km/h), and this general motion is forecast to 
continue today.  A faster northeastward motion is expected to begin 
by tonight and continue on Tuesday.  On the forecast track, the 
center of Ida will move farther inland over southeastern Louisiana 
early this morning and move into southwestern Mississippi later 
this morning. Ida is then forecast to move over central and 
northeastern Mississippi this afternoon and tonight, and move across 
the Tennessee Valley on Tuesday.
 
Maximum sustained winds have decreased to near 75 mph (120 km/h) 
with higher gusts. Additional rapid weakening is forecast during 
the next day or so, and Ida is expected to become a tropical storm 
later this morning.
 
Hurricane-force winds extend outward up to 30 miles (45 km) from
the center and tropical-storm-force winds extend outward up to 140
miles (220 km).  During the past hour, a sustained wind of 57 mph 
(92 km/h) and a gust to 68 mph (109 km/h) were measured by a 
Weatherflow station in Mandeville, Louisiana. Along the Gulf coast, 
a NOAA Ocean Service observing station at Bay Waveland Yacht Club, 
Mississippi, recently reported a sustained wind of 43 mph (69 km/h) 
and a gust to 54 mph (87 km/h).
 
The estimated minimum central pressure is 972 mb (28.70 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...
 
Morgan City, LA to Bay St. Louis, MS including Lake
Borgne...7-11 ft
Lake Pontchartrain...5-8 ft
Bay St. Louis, MS to Ocean Springs, MS...4-7 ft
Lake Maurepas...4-6 ft
Ocean Springs to AL/FL border including Mobile Bay...3-5 ft
Intracoastal City, LA to Morgan City, LA including Vermilion
Bay...1-3 ft
AL/FL border to Okaloosa/Walton County Line including Pensacola
Bay...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:  Wind damage is likely near the core of Ida as it moves 
farther inland over southeastern Louisiana during the next few 
hours.
 
Hurricane conditions will spread farther inland within the Hurricane
Warning area over southeastern Louisiana for the next couple of 
hours.  Tropical storm conditions will also spread inland over 
portions of Louisiana and Mississippi through this morning.
 
RAINFALL:  Heavy rainfall from Ida will continue to impact the
southeast Louisiana coast, spreading northeast into the Lower
Mississippi Valley today.  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 
today. This is likely to result in life-threatening flash and urban 
flooding and significant river flooding impacts.

Ida is forecast to turn to the northeast today 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
morning.
 
Central Mississippi: 4 to 8 inches, with isolated maximum amounts of
12 inches, through tonight.
 
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 this morning 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 later today.
 
SURF:  Swells will continue to affect the northern Gulf coast
through today.  These swells are likely to cause life-threatening
surf and rip current conditions. Please consult products from your
local weather office.
 
 
NEXT ADVISORY
-------------
Next complete advisory at 400 AM CDT.

Hourly Tropical Cyclone Updates are being discontinued after the 
100 AM CDT Intermediate Advisory.
 
$$
Forecaster Stewart
 
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