Many things can influence weather throughout the world like altitude, atmospheric moisture, latitude, temperature, winds and large bodies of water. A large body of water that affects Coastal Mississippi is the Gulf of Mexico. This body of water plays the biggest part of the weather of Coastal Mississippi throughout the year. You can see the biggest influences of its effect on Coastal Mississippi during the winter and summer.
The Gulf of Mexico has the biggest influence on the weather of Coastal Mississippi because it is the ninth largest body of water in the world covering ever mile of Coastal Mississippi. The Gulf of Mexico is a warm body of water with temperatures averaging around high 60s in January and as high as the low 90s in July and August (1).
The temperature of the water affects the weather of Coastal Mississippi by brings warm moist air to the region. This warm moist air rises causing a variety of weather from fog to thunderstorms to fueling tropical storms and hurricanes. Forecasting for variety of weather for the Coastal Mississippi area can be challenging due to all the factors that the Gulf of Mexico can affect throughout the year.
During the winter, the Gulf of Mexico will provide warmth and moisture to Coastal Mississippi. The warming that the gulf causes affects the temperature of the air and the land. Coastal Mississippi will be on average 10 degrees Fahrenheit warmer than central and northern Mississippi with the temperatures around the coastal area 65 during the day and low 40s at night. The Gulf of Mexico acts as a heating mechanism for the coastal area. The Gulf of Mexico will also be warmer than the land around the coastal area causing a warm moist air to move over the land during the early mornings bring advection fog to the Coastal Mississippi. The advection fog cause problems with visibility and traffic problems all along the coastal areas. The visibility issues affect both traffic on the road and aviation limiting the range of sight for on the airfields and flights coming into land.
During the spring and fall, the Gulf of Mexico can affect the weather by providing the moisture needed to bring on rain showers and thunderstorms. The warm moist air coming up from the south over the land will collide with the cool dry air from the polar jet stream that still pushes south from the north causing the development of thunderstorms and squall lines. The thunderstorms can bring heavy rains to the region, which can cause flooding and damages to property. Coastal Mississippi averages 61 inches of rain a year and Northern Mississippi averages 50 inches a year (2). The warm moist air from the south mixing with the cool dry air from the north can bring tornados along with the thunderstorms too. The state of Mississippi averages 27 tornados year round with the northern part of the state being more severe in the spring and the coastal area being more severe in the fall (2). During the early parts of spring, there is enough temperature difference between the land and water that advection fog is still a problem for the coastal area.
During the summer, the Gulf of Mexico influences the weather around Coastal Mississippi the most. The coastal area will experience a variety of weather during the summer from simple sea breeze to the convective thunderstorms the build up in the afternoons. The sea breezes are brought on by the temperature difference from the land and the gulf. As the land heats up from daytime heating, the winds will shift around to the south bring a sea breeze from the Gulf of Mexico since a high pressure will from over the water and a low pressure over the land. As the sea breezes take affect during the afternoons, they push the moist warm air that is rising due to the heating during the day over the land. The air will then start to form cumulus clouds that will build, as the day gets warmer and more moisture rises form cumulonimbus clouds. As the warm air rises and expands forming the cumulonimbus clouds, they develop into thunderstorms and rain showers. The Gulf of Mexico has a major influence on tropical storms and hurricanes that are tracking towards Coastal Mississippi. The Gulf will get to temperatures around 90 degrees Fahrenheit during the summer, which for tropical storms and hurricanes to develop, the water temperature needs to be above 80 degrees. As a tropical storm or hurricane moves into the Gulf of Mexico, it will intensify in strength and size, which will give it a greater chance of making land fall somewhere along Coastal Mississippi. As the tropical storm or hurricane approaches the coastal area, it brings sea surges, high winds, thunderstorms and heavy rain showers to the area causing damage to property and possibly deaths. During the 2005 hurricane season, Hurricane Katrina made landfall in August and 238 people died during the storm in the Coastal Mississippi area (3).
Throughout the year, the Gulf of Mexico affects the weather of Coastal Mississippi and forecasting for it can be a challenge. Forecasting for the advection fog is a challenge during the winter and early springs as the forecaster needs to compare the surface wind charts, temperature readings of the land and water, and look at surface pressure charts to see if high pressure will be present in the early mornings before daytime heating occurs. Forecasting for the thunderstorms and tornadoes that occur in the spring becomes a challenge as you compare the upper level charts to see if the polar jet stream is tracking far enough south that it will bring cool dry air into the area to collide with the warm moist air that is pushing up from the south from the Gulf of Mexico. During the summer, the forecaster needs too see how quickly the day will start to heat up causing the sea breeze to take affect. The earlier in the day that the sea breeze takes affect, the greater chance that the area will experience thunderstorms that day. The forecaster needs to look at the moisture levels in the atmosphere as well as to see what if there is a lifting mechanism that will cause the warm moist air to rise to greater heights in the atmosphere, which helps produce the afternoon thunderstorms and rain showers. As the thunderstorms start to dissipate, that is usually when the rain showers will begin. Forecasting for tropical storms and hurricanes that are tracking towards Coastal Mississippi can be difficult due to the lack of weather reports you can receive as the storm is over the water. Satellite will give you a good idea of how high cloud tops are within the storm, temperature of water and the temperature within the storm. Tropical storms typical follow a general path as they enter the Gulf of Mexico but are always able to change direction without any signs of it happening.
The accuracy of the charts and satellites that the forecaster uses affects how accurate their forecast will be. The better charts that exam all factors from winds to temperature to moisture need to be as up to date as possible and looking at how the systems are moving. The satellite images that are examined need to be a loop of images without an images missing from the loop to be able to see if any weather systems are moving into the area or to locate the different pressure regions.
(1) Weatheratlas.com; article on the Climate of Mississippi;
(2) Wikipedia.com; article on the State of Mississippi;
(3) Wikipedia.com; article on Hurricane Katrina;