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Potential Tropical Cyclone Three Intermediate Advisory Number 2A
NWS National Hurricane Center Miami FL AL032021
100 AM CDT Fri Jun 18 2021
...POTENTIAL TROPICAL CYCLONE THREE FORECAST TO BRING HEAVY
RAINFALL AND FLOODING TO THE NORTHERN GULF COAST...
SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION
ABOUT 390 MI...630 KM S OF MORGAN CITY LOUISIANA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 9 MPH...15 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...
* Intracoastal City Louisiana to the Alabama/Florida border
* 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
to 24 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 AM CDT (0600 UTC), the poorly defined disturbance was
centered near latitude 24.0 North, longitude 92.0 West. The system
is moving toward the north near 9 mph (15 km/h), and this motion
with some increase in forward speed is expected for the next day or
so. On the forecast track, the system will approach the
north-central Gulf Coast late Friday or early Saturday. A
northeastward motion across the southeastern United States is
likely after landfall.
Satellite-derived wind data indicate that 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 west-central or northwestern Gulf of Mexico
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.
The estimated minimum central pressure is 1007 mb (29.74 inches).
HAZARDS AFFECTING LAND
Key messages for Potential Tropical Cyclone Three can be found in
the Tropical Cyclone Discussion under AWIPS header MIATCDAT3 and
WMO header WTNT43 KNHC.
RAINFALL: 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. Rainfall totals of
4 to 8 inches with isolated maximum amounts of 12 inches are
possible beginning today and continuing through the weekend from
along the Central Gulf coast, northeastward into the southern
Appalachians. This will likely produce areas of flash, urban and
small stream flooding as well as minor to isolated moderate river
flooding with new and renewed rises on already elevated rivers.
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...
Intracoastal City, LA to MS/AL Border...2-3 ft
Vermilion Bay and Lake Borgne...2-3 ft
Lake Pontchartrain and Lake Maurepas...1-2 ft
MS/AL border to AL/FL border including Mobile Bay...1-3 ft
Cameron, LA to Intracoastal City, LA...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 couple of tornadoes is expected to
begin this afternoon across coastal Louisiana. This threat should
expand northward across southern portions of Louisiana and
Mississippi, and southwest Alabama Friday night into Saturday.
Next complete advisory at 400 AM CDT.