John Grymes | 4/19/2005 10:28:32 PM
We may be only half way through 2004, but many Louisiana residents feel like they have already experienced more than a year's worth of weather, according to LSU AgCenter climatologist Jay Grymes.
Over the past six months, portions of the Pelican State have suffered dry spells and heavy rains, severe weather and river flooding, even a Valentine's Day snowstorm. But history tells us that such apparent weather mis-behavior is not unusual, Grymes points out.
"Winter and spring often are defined by a mixed bag of weather for Louisiana, and 2004 has fit that mold," the climatologist says, explaining, "These are the seasons when frontal systems are the weather ‘drivers’ for the Bayou State, and the time of year when severe weather can be most threatening."
Powerful thunderstorms, energized by the collision of moist Gulf air with colder and drier air masses from the north, are capable of producing excessive downpours, dangerous lightning, damaging winds and occasional tornadoes.
Grymes says Louisiana weather records have logged numerous accounts of these types of severe-weather events already this year. In addition to these short-term weather episodes, 2004 has been marked by extended weather trends. After a wetter-than-normal February, which resulted in basin flooding along several south Louisiana rivers, relatively dry weather set-in during March and April, with a brief run of near-drought conditions for many eastern and southeastern parishes.
That short, dry spell was terminated in dramatic fashion during mid-May, when a 10-day run of stormy weather produced as much as 10-20 inches of rain for parts of the state, prompting widespread flooding across the southern half of the state and leaving sections of Louisiana with the wettest May on record!
What can we expect for the upcoming weeks and months? "As we head into the heart of the summer months, the importance of frontal weather wanes as our regional weather controls become dominated by the Gulf of Mexico in the form of Louisiana's infamous heat and humidity," Grymes says.
He adds that by mid summer, the state typically displays a steep south-to-north rainfall gradient, with southern parishes recording roughly twice the amount of rain as those areas along and north of the I-20 corridor. Furthermore, the unpredictable, "hit and miss" nature of much of our summer shower activity can result in considerable differences in soil-moisture conditions, even within the same parish.
Speaking from experience, Grymes says, "For many of Louisiana's professional weathercasters, summer season forecasting can be among the most difficult."
Given the uncertainties of summer forecasts, the climatologist nonetheless expects no unusual weather departures this summer. In other words, he says to plan on our usual heat, humidity and scattered mainly-afternoon showers.
For information on related topics, visit the AgCenter Web site at www.lsuagcenter.com. For local information and educational programs, contact an extension agent in your parish LSU AgCenter office.