El Nino develops; what this may mean for Mississippi

NARROW BAND IN THE EASTERN PACIFIC WARMS DURING THE MONTH OF JUNE

National Oceanic and Atmospheric Administration (NOAA) announced the arrival of El Nino, a climate phenomenon with a significant influence on global weather, ocean conditions, and marine fisheries. 

El Nino is the periodic warming of the central and eastern tropical Pacific waters. 

Forecasters say the sea surface temperature climbed to 1.8 degrees Fahrenheit above normal along a narrow band in the eastern equatorial Pacific in June.

NOAA is projecting the influence of El Nino will further develop and continue to effect the Northern Hemisphere, through this upcoming Winter.

El Niño's impacts depend on a variety of factors, such as intensity and extent of ocean warming, and the time of year.

The most recent intense El Nino occurred in 1997/98 .

El Nino 1997/98,  killed more than 2,000 people and caused billions of dollars in damage to crops, infrastructure, ports and mines.

NOAA officials noted that not all El Nino effects are negative. It can suppress Atlantic hurricanes and bring needed moisture to the arid Southwest.

Climate Prediction Center (National Weather Service Agency -that maintains a continuous watch on short term climate fluctuations and diagnoses and predicts them) said, 

current trends favor development "of a weak-to-moderate strength" El Nino into the northern hemisphere winter of 2009, "with further strengthening possible thereafter."

 El Nino episodes tend to develop from March to June and reach peak intensity during the December to April period, weakening from May to July. Prolonged El Nino episodes have lasted 2 years and even as long as 3 to 4 years.

WHAT EFFECTS MAY THIS EL NINO BRING TO  MISSISSIPPI AND SURROUNDING AREAS?

One effect of this pattern for the state is that the late Fall and Winter seasons tend to be colder than normal and the Spring and Summer seasons tend to be warmer than normal.

This pattern also causes precipitation totals to be higher than normal in the Winter and Spring but drier than normal in the Summer.

(Some of the effects of a typical El Nino are currently ongoing across the state. It has been drier than normal across Central and Southern Mississippi, with some areas recording their driest June ever.  Plus,  it has been hotter than normal with many locations across Central and Southern Mississippi, soaring into the upper 90s and above 100 degrees, for extended periods of time, during the month of June, making it one of the hottest months of June in years!)

During El Nino events, the subtropical jet stream commonly becomes much more active across the southern United States.  This increases the number of storm systems that move along the gulf coast, during the winter and spring seasons. Also, increasing the tornado threat along the gulf coast. 

In addition, due to the wetter pattern that commonly is known with the effects of El Nino combined with the occasional intrusions of colder air into the South during the winter months, snow chances actually increase across the state.

Historically, moderate to strong El Niño episodes have produced (1 to 2 inches of rainfall) over the entire state, during November and December. 

During January-March, precipitation has averaged below normal in the northern third of the state, near normal in central portions, and above normal in the south.

[During the 1982-83 El Nino episode, the western half of the state received excess precipitation of 12 to 15 inches during November-December, and the southern half of the state received excess rainfall of up to 7 inches during January-March] 

As for hurricane season, El Nino significantly decreases the number of hurricanes in the Atlantic during the peak of  hurricane season, limiting  the threat to the Gulf Coast States.