ZCZC MIATCPAT3 ALL
TTAA00 KNHC DDHHMM
Potential Tropical Cyclone Three Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL AL032021
100 PM CDT Fri Jun 18 2021
...DISTURBANCE A LITTLE STRONGER...
...HEAVY RAINFALL AND TROPICAL-STORM-FORCE WINDS BEGINNING TO REACH
PORTIONS OF THE NORTHERN GULF COAST...
SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
ABOUT 165 MI...265 KM S OF MORGAN CITY LOUISIANA
ABOUT 295 MI...480 KM SSW OF MOBILE ALABAMA
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...N OR 15 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* East of Morgan City, Louisiana to the Okaloosa/Walton County line
* Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 6-12 hours.
Interests elsewhere along the northern Gulf Coast should monitor
the progress of this system.
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 disturbance was centered near latitude
27.3 North, longitude 91.1 West. The system is moving toward the
north near 14 mph (22 km/h), and a north to north-northeast motion
is expected during the next day or so. On the forecast track, the
system will make landfall along the north-central Gulf Coast
tonight or early Saturday. A northeastward motion across the
southeastern United States is likely after landfall through the
Satellite data indicate that maximum sustained winds have increased
to near 45 mph (75 km/h) with higher gusts. The circulation is
gradually becoming better defined, and a tropical storm is likely to
form over the north-central Gulf of Mexico later today or tonight.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.
Tropical-storm-force winds extend outward up to 205 miles east of
the center. A NOAA C-MAN station at the Southwest Pass of the
Mississippi River recently reported sustained winds of 44 mph (71
km/h) and a wind gust of 51 mph (82 km/h) at an elevation of 125
feet (38 meters).
The estimated minimum central pressure based on data from the Air
Force Hurricane Hunters and surface observations is 1007 mb (29.74
HAZARDS AFFECTING LAND
Key messages for Potential Tropical Cyclone Three can be found in
the Tropical Cyclone Discussion under AWIPS header MIATCDAT3,
WMO header WTNT43 KNHC, and on the web at
RAINFALL: Rainfall totals of 4 to 8 inches with isolated maximum
amounts of 12 inches are expected across portions of the Central
Gulf Coast beginning today. Considerable flash, urban and small
stream flooding impacts as well as new and renewed minor to isolated
moderate river flooding are likely.
As the system continues to lift northeast through the weekend,
anticipate heavy rain to expand across southeastern Mississippi,
southern and central Alabama, and central Georgia resulting in
rainfall totals of 3 to 5 inches with isolated maximum amounts of 7
inches. Flash, urban, small stream and isolated minor river flooding
impacts are possible.
The potential tropical cyclone is expected to produce total
rainfall of 3 to 6 inches with isolated amounts of 8 inches across
the Yucatan Peninsula of Mexico.
STORM SURGE: The combination of 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 Okaloosa/Walton County Line, FL...2-3 ft
Lake Borgne and Mobile Bay...2-3 ft
Lake Pontchartrain and Lake Maurepas...1-2 ft
Okaloosa/Walton County Line, FL to Panama City, FL...1-2 ft
Pensacola Bay, Choctawhatchee Bay, and Saint Andrew Bay...1-2 ft
Cameron, LA to Morgan City, LA...1-2 ft
Vermilion Bay...1-2 ft
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: Tropical storm conditions are beginning to reach the coast
within the warning area, and these winds will continue into
TORNADOES: There is a threat for a tornado or two this afternoon
across coastal Louisiana, spreading overnight into Saturday across
southern portions of Louisiana, Mississippi, Alabama, and the
western Florida Panhandle.
Next complete advisory at 400 PM CDT.