HURRICANE LARRY







HURRICANE LARRY

Coastal Watches/Warnings and Forecast Cone for Storm Center

cone graphic

* If the storm is forecast to dissipate within 3 days, the “Full Forecast” and “3 day” graphic will be identical

Click Here for a 5-day Cone Printer Friendly Graphic

How to use the cone graphic (video):

Link to video describing cone graphic

About this product:

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink),
tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the
center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center
at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be
tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed,
then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time:

D: Tropical Depression – wind speed less than 39 MPH
S: Tropical Storm – wind speed between 39 MPH and 73 MPH
H: Hurricane – wind speed between 74 MPH and 110 MPH
M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast
uncertainty is conveyed by the track forecast “cone”, the solid white
and stippled white areas in the graphic. The solid white area depicts
the track forecast uncertainty for days 1-3 of the forecast, while the
stippled area depicts the uncertainty on days 4-5. Historical data
indicate that the entire 5-day path of the center of the tropical
cyclone will remain within the cone about 60-70% of the time. To
form the cone, a set of imaginary circles are placed along the
forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions,
where the size of each circle is set so that it encloses 67% of the
previous five years official forecast errors. The cone is then formed
by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their
effects can span many hundreds of miles from the center. The area
experiencing hurricane force (one-minute average wind speeds of at least
74 mph) and tropical storm force (one-minute average wind speeds of
39-73 mph) winds can extend well beyond the white areas shown enclosing
the most likely track area of the center. The distribution of hurricane
and tropical storm force winds in this tropical cyclone can be seen in
the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the
chances that any particular location will experience winds of 34 kt (tropical storm force),
50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in

tabular form for selected locations and forecast positions. This information is also presented in
graphical form for the 34 kt, 50 kt,
and 64 kt thresholds.

Note:  A detailed definition of the NHC track forecast cone is also available.




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Hurricane Ida Public Advisory



000
WTNT34 KNHC 282353
TCPAT4

BULLETIN
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
----------------------------------------------
LOCATION...26.6N 87.5W
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:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* East of Rockefeller Wildlife Refuge 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,
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
Borgne...7-11 ft
Intracoastal City, LA to Morgan City, LA including Vermilion
Bay...6-9 ft
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
flooding impacts.

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
mudslides.

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 ADVISORY
-------------
Next complete advisory at 1000 PM CDT.

$$
Forecaster Cangialosi



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