The Threat Invest 95L Poses to the Gulf Coast
Invest 95L Satellite Imagery, Image: NOAA
National Weather Service link tracking Gulf Low. (Click on the Gulf Low tab above the radar imagery.)
Meteorologists across the Gulf Coast are closely watching Invest 95L despite its lack of organization and poor chance of development. With oil still gushing from the bottom of the Gulf of Mexico, this low and its associated wind and wave action could drive more oil into sensitive marshes and estuaries along the northern Gulf Coast. Yesterday, hurricane specialists Lixion Avila and Chris Landsea identified the low and gave it a 10% chance of development. We’d already had our eye on it in the FOX 8 Weather Department. Today, Avila and Landsea give it a 20% chance.
Stalled Frontal Boundary, Image: Unisys
In early June and July, the main source of tropical development in the Gulf of Mexico is a low that forms off of a stalled frontal boundary in the gulf. You can see the position of the low is about 150 miles or so south-southeast of the boot of Louisiana. There’s a lot of wind shear and dry air affecting the low right now keeping it from developing into anything tropical. Wind shear is expected to remain fairly strong over the next couple of days. So, for this thing to develop, wind shear has to relax and the dry air will have to be replaced by a warm and tropical air mass.
Water Vapor Imagery, Image: NOAA
More troubling for Gulf Coast residents is the wind and wave action associated with a low pressure system east of Louisiana. With oil gushing offshore, a persistent southeast wind could drive the oil onshore. Wave heights are currently about 5 feet around the location of the Deepwater Horizon Incident. Wave heights are forecast to become 6′ offshore, keeping skimmers and other cleanup craft in safe harbor.
-Dawn Brown
Advection Fog
Fog is a cloud that is actually on the ground! There are many different ways that fog forms. What’s behind advection fog, though, is pretty interesting. Advection fog is most common along the West Coast of The United States during the spring and first few months of summer. In fact, most of the fog that affects San Francisco, and the nearby coastal areas, is due to the advection fog process. Namely the fog that affects the West Coast is known as sea fog, Advection fog may last for hours, or even days.
Advection Fog From Above
The way advection fog, or more specifically sea fog, is winds blow over warm water that is relatively far out to sea. There, the air picks up warmth and moisture. The winds then take that air and drag it over cooler water nearer to the coast. This process condenses the water vapor out of the air and develops the cloud. The winds then take the cloud, which is near the surface of the water, and drag it over the near-shore areas of the land.
Advection fog can also occur in interactions between warmer water and cool landmass areas.
In fact, advection fog can occur during other seasons and in other parts of the country. On a smaller scale, advection sea fog occurs in the Gulf South during the wintertime months. Here, winds out of the southeast drag air over the warm waters of the central Gulf of Mexico and eventually over much cooler near-shore waters developing fog over places like New Orleans and Southeastern Louisiana. In fact, sea fog will be socking in Boothville in far southeast Louisiana prompting fog advisories through Friday morning.
US Watches & Warnings, Image: NOAA