1. Gusty winds, heavy rainfall, and lingering coastal flooding are expected from Marco along portions of the Gulf Coast through this evening. For information on these hazards see products from your local National Weather Service office.

2. Tropical Storm Laura could bring dangerous storm surge, rainfall, and wind impacts to portions of the U.S. Gulf Coast by themiddle of the week, and tropical cyclone wind and surge watches and warnings could be issued for portions of the U.S. Gulf Coast later today.

CHANGES WITH THIS ADVISORY:

The Tropical Storm Warning and Storm Surge Warning for the U.S. Gulf Coast have been discontinued.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

There are no coastal watches or warnings in effect.

Gusty winds, heavy rainfall, and lingering coastal flooding are expected from Marco along portions of the Gulf Coast through this evening. For information on these hazards see products from your local National Weather Service office.

Tropical cyclone wind and surge watches or warnings are likely to be issued for portions of the U.S. Gulf Coast later today for Tropical Storm Laura.

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.

WIND: Wind gusts to tropical storm force are possible over the coastal sections of southeastern Louisiana and Mississippi through this evening.

RAINFALL: Marco is expected to produce total rainfall accumulations of 2 to 4 inches with isolated maximum amounts of 7 inches across portions of the northeast and northcentral Gulf coast through Tuesday. This 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 for the next day or so. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

TORNADOES: A couple of tornadoes are possible today into tonight across the Florida Panhandle, southern Georgia, southern Alabama, and southern Mississippi.

At 100 PM CDT (1800 UTC), the center of Tropical Storm Marco was located near latitude 28.7 North, longitude 88.6 West. Marco is moving toward the northwest near 6 mph (9 km/h). A turn to the westnorthwest is expected to occur by Tuesday, and this motion should continue until the system dissipates in a couple of days.

Aircraft and satellite derived wind data indicate that maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Further weakening is expected, and Marco is forecast to become a tropical depression tonight and degenerate to a remnant low on Tuesday.

Tropicalstormforce winds extend outward up to 80 miles (130 km) to the northeast of the center over water. A National Ocean Service weather station located on Petit Bois Island, Mississippi recently reported a wind gust to 35 mph (58 km/h).

The latest minimum central pressure reported by aircraft reconnaissance is 1008 mb (29.77 inches).

Marco continues to weaken as the deep convection has been stripped away from the center since this morning. An Air Force ReserveHurricane Hunter aircraft currently investigating the system has reported peak 925 mb flight level winds of 38 kt. Although there have been a few recent higher SFMR measurements that are due to rain contamination, a recent ASCAT overpass revealed only a small area of 30-35 kt winds. Based on these data the initial intensity is being lowered to 35 kt and a special advisory has been issued to update the short-term intensity forecast and discontinue warnings for the Gulf coast.

The showers and thunderstorms generating the tropical storm force winds to the northeast of Marco's center are forecast by most models to gradually dissipate through this evening. Based on how quickly the vortex has been spinning down and the anticipated decrease of convection, it is reasonable to assume that sustained tropical storm force winds will no longer reach the northern Gulf coast. Therefore, all wind and surge warnings for the Gulf coast associated with Marco have been discontinued. Shortly after the cyclone reaches the Gulf Coast later tonight it should degenerate to a remnant low, with this low dissipating inland within a couple of days. The latest intensity forecast was adjusted downward through 12 h, but remains the same as the previous NHC forecast thereafter.

Marco has been moving slowly all day, and an initial motion estimate is now 320/5 kt. There is no change to the forecast track reasoning. As the cyclone continues to weaken and degenerates to a remnant low, a turn to the west-northwest is expected as the system becomes steered in the low level flow. The latest forecast track was adjusted slightly northward through 12 h, but remains the same as the previous one until the system dissipates.This special advisory package replaces the 100 PM CDT (1800 UTC) intermediate public advisory.