THE INFLUENCES OF THE GULF OF MEXICO
ON COASTAL MISSISSIPPI WEATHER
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FRANK LENNON
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.
References:
(1) Weatheratlas.com; article on the Climate of Mississippi;
http://www.worldatlas.com/webimage/countrys/namerica/usstates/msweather.htm
(2) Wikipedia.com; article on the State of Mississippi;
http://en.wikipedia.org/wiki/Mississippi
(3) Wikipedia.com; article on Hurricane Katrina;
http://en.wikipedia.org/wiki/Hurricane_Katrina
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