UPDATED 11:30 P.M. Marco weakens; Laura expected to become hurricane Tuesday
NATIONAL HURRICANE CENTER
TROPICAL STORM LAURA
Advisory Number 21
NWS National Hurricane Center Miami FL AL132020
1100 PM EDT Mon Aug 24 2020
...LAURA FORECAST TO BECOME A HURRICANE ON TUESDAY...
...HEAVY RAINS AND FLASH FLOODING CONTINUES OVER WESTERN CUBA...
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.7N 84.0W
ABOUT 80 MI...130 KM NE OF THE WESTERN TIP OF CUBA
ABOUT 765 MI...1230 KM SE OF LAKE CHARLES LOUISIANA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
The Tropical Storm Warning for the Middle Florida Keys has been
discontinued.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Watch is in effect for...
* San Luis Pass Texas to Ocean Springs Mississippi
* Lake Pontchartrain, Lake Maurepas, and Lake Borgne
A Hurricane Watch is in effect for...
* Port Bolivar Texas to west of Morgan City Louisiana
A Tropical Storm Warning is in effect for...
* Cuban provinces of Villa Clara, Cienfuegos, Matanzas, Mayabeque,
La Habana, Artemisa, Pinar del Rio, and the Isle of Youth
* Florida Keys from the Seven Mile Bridge to Key West
* Dry Tortugas
A Tropical Storm Watch is in effect for...
* South of Port Bolivar to San Luis Pass Texas
* Morgan City Louisiana to the Mouth of the Mississippi River
A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.
A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.
DISCUSSION AND OUTLOOK
----------------------
At 1100 PM EDT (0300 UTC), the center of Tropical Storm Laura was
located near latitude 22.7 North, longitude 84.0 West. Laura is
moving toward the west-northwest near 20 mph (31 km/h) and this
general motion with some decrease in forward speed is expected over
the next day or so. A turn toward the northwest is forecast by
Wednesday, and a northwestward to north-northwestward motion should
continue through Wednesday night. On the forecast track, the center
of Laura will move away from Cuba and over the southeastern Gulf of
Mexico overnight. Laura is then forecast to move over the central
and northwestern Gulf of Mexico Tuesday night and Wednesday, and
approach the northwestern coast of the Gulf of Mexico Wednesday
night.
Maximum sustained winds are near 65 mph (105 km/h) with higher
gusts. Strengthening is expected, and Laura is foreast to become a
hurricane on Tuesday. Additional strengthening is forecast on
Wednesday, and Laura could be near major hurricane strength when it
approaches the coast.
Tropical-storm-force winds extend outward up to 175 miles (280 km)
from the center.
The estimated minimum central pressure based on data from the NOAA
and Air Force Hurricane Hunters is 996 mb (29.42 inches).
HAZARDS AFFECTING LAND
----------------------
Key messages for Laura can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC.
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...
High Island TX to Morgan City LA including Sabine Lake, Calcasieu
Lake, and Vermilion Bay...7-11 ft
Port Bolivar TX to High Island TX...4-6 ft
Morgan City LA to Mouth of the Mississippi River...4-6 ft
Mouth of the Mississippi River to Ocean Springs MS including Lake
Borgne...3-5 ft
San Luis Pass TX to Port Bolivar TX...2-4 ft
Galveston Bay...2-4 ft
Lake Pontchartrain and Lake Maurepas...2-4 ft
The deepest water will occur along the immediate coast near and to
the right of the landfall location, where the surge will be
accompanied by large and destructive 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.
RAINFALL: Laura is expected to produce the following storm total
rainfall accumulations into tonight:
Western Cuba: 4 to 6 inches, with maximum amounts of 10 inches.
This heavy rainfall could lead to life-threatening flash and urban
flooding, and the potential for mudslides.
From Wednesday afternoon into Saturday, Laura is expected to produce
rainfall of 4 to 8 inches, with isolated maximum amounts of 12
inches across portions of the west-central U.S. Gulf Coast near the
Texas and Louisiana border north into portions of the lower
Mississippi Valley. This rainfall could cause widespread flash and
urban flooding, small streams to overflow their banks, and minor to
isolated moderate river flooding.
WIND: Tropical storm conditions are expected to spread westward
within the warning area in western Cuba during the next few hours.
Tropical storm conditions are also expected within the warning area
in the middle and lower Florida Keys and the Dry Tortugas tonight.
Hurricane conditions are possible in the hurricane watch area along
the Gulf Coast by late Wednesday, with tropical storm conditions
possible by Wednesday afternoon.
SURF: Swells generated by Laura are affecting portions of Cuba, the
central Bahamas, and the Florida Keys. Swells are expected to
spread northward along portions of the west coast of Florida
peninsula and the coast of the Florida panhandle on Tuesday
and Tuesday night, and reach the northern and northwest Gulf coast
by Wednesday. These swells are likely to cause life-threatening surf
and rip current conditions. Please consult products from your
local weather office.
NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.
TROPICAL STORM MARCO
Tropical Depression Marco Advisory Number 20
NWS National Hurricane Center Miami FL AL142020
1000 PM CDT Mon Aug 24 2020
...MARCO WEAKENS TO A TROPICAL DEPRESSION...
...HEAVY RAIN STILL POSSIBLE TONIGHT ACROSS PORTIONS OF THE CENTRAL
GULF COAST...
SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...29.0N 89.8W
ABOUT 45 MI...70 KM W OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
None.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
There are no coastal watches or warnings in effect.
DISCUSSION AND OUTLOOK
----------------------
At 1000 PM CDT (0300 UTC), the center of Tropical Depression Marco
was located near latitude 29.0 North, longitude 89.8 West. The
depression is moving toward the west near 9 mph (15 km/h). Marco is
forecast to continue moving westward near the coast of Louisiana
for the next day or so.
Maximum sustained winds have decreased to near 35 mph (55 km/h) with
higher gusts. Additional weakening is expected, and Marco is
forecast to become a remnant low on Tuesday. The system is then
forecast to dissipate by early Wednesday.
The estimated minimum central pressure is 1007 mb (29.74 inches).
HAZARDS AFFECTING LAND
----------------------
RAINFALL: Marco is expected to produce additional rainfall
accumulations of 1 to 3 inches with additional isolated totals of 5
inches across portions of the north-central Gulf coast and
Southeastern United States through Wednesday. Rain totals related
to Marco near Apalachicola, Florida reached as high as 11.81 inches
on Sunday per a CoCoRaHS report. The additional rainfall may result
in areas of flash, urban and small stream flooding along the same
area.
SURF: Swells generated by Marco are likely to affect portions of
the northern Gulf Coast overnight. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.
TORNADOES: A brief tornado or two remains possible overnight across
the Florida Panhandle, southwest Georgia, far southern Alabama, and
far southern Mississippi.
NEXT ADVISORY
-------------
Next complete advisory at 400 AM CDT.
$$
Forecaster Zelinsky