ZCZC MIATCPAT3 ALL
TTAA00 KNHC DDHHMM
Potential Tropical Cyclone Three Advisory Number 4
NWS National Hurricane Center Miami FL AL032021
1000 AM CDT Fri Jun 18 2021
...HEAVY RAINFALL AND GUSTY WINDS BEGINNING TO REACH PORTIONS OF
THE NORTHERN GULF COAST...
SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
ABOUT 220 MI...355 KM S OF MORGAN CITY LOUISIANA
ABOUT 340 MI...550 KM SSW OF MOBILE ALABAMA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Tropical Storm Warning has been discontinued from Morgan City
westward to Intracoastal City, Louisiana.
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 12
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 1000 AM CDT (1500 UTC), the disturbance was centered near
latitude 26.5 North, longitude 91.1 West. The system is moving
toward the north-northeast near 14 mph (22 km/h) and this general
motion is expected for 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 slow northeastward motion across the
southeastern United States is likely after landfall through the
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast, and a subtropical or tropical
storm is likely to form over the central or northern Gulf
of Mexico later today.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.
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 expected to first reach the
coast within the warning area later today, making outside
preparations difficult or dangerous.
TORNADOES: The threat for a tornado or two will begin this afternoon
across coastal Louisiana, then spread overnight into Saturday across
southern portions of Louisiana, Mississippi, and Alabama, to the
western Florida Panhandle.
Next intermediate advisory at 100 PM CDT.
Next complete advisory at 400 PM CDT.