Odd Weather Cripples Harvest Says LSU AgCenter Climatologist

John Grymes  |  4/19/2005 10:28:38 PM

News You Can Use For November 2004

Smaller harvests are expected for most major Louisiana crops in 2004. Blame the combined effects of the unusually wet spring and the abnormally dry mid to late summer, says LSU AgCenter weather specialist and extension climatologist Jay Grymes.

Eight-week rain totals through May and June averaged 20 inches or more across most of the state, ranking as Louisiana's second wettest May-June in more than 100 years, Grymes says. The two-month deluge flooded fields and left standing water for weeks at a critical time for crop development. The result: near-total losses for many parishes, forcing some farmers to start over.

A much-needed drying-out began in July, as many parishes benefited from below-normal rain for that month.

"Unfortunately, what began as a welcomed dry spell rolled right into a prolonged run of near-drought weather through August and September for many south Louisiana parishes," Grymes notes.

Summer months are typically among the driest in the northern parishes, but wettest in the southern third of the state. August 2004 rains actually averaged a bit above the norm for most of northern Louisiana, while a number of southern parishes received less than 50 percent of their monthly norm. As the dry pattern extended into September, signs of moisture stress and the potential for wildfires were more and more apparent across many south Louisiana parishes.

"Summertime variations in weather can be very pronounced, even within a relatively small state like ours, and such regional variations became quite apparent during the late summer," the climatologist explains.

Although August-plus-September rains for much of northwestern Louisiana were above normal, rain totals over much of the remainder of the state were well below average, with the statewide August-September total of 5.5 inches, ranking it among the 10 lowest since the 1890s.

Some areas reported exceptionally low sums, with a number of central and east-central parishes averaging less than 3 inches of rain for the eight-week period.

"Rain shortages during the summer months can be particularly stressful," Grymes says, explaining that this is the time of year with the highest rates of evaporation and environmental moisture demand. As a result, the U.S. Drought Monitor (www.drought.unl.edu/dm/) posted the entire eastern half of the Bayou State as "unusually dry" (approaching drought status) as of early October.

Tropical Storm Matthew, however, abruptly ended the drought threat. "Not only did the ‘hit-and-run’ storm prove to be a drought-buster, but the tropical system's double-digit rains over portions of the Bayou State produced a flip-flop of concerns for a number of parishes in southeastern Louisiana," Grymes reports. Areas suffering from water shortages just days before Matthew's arrival were now bailing out from excessive floodwaters.

"While the overall impact of Matthew's rains on Louisiana agriculture will continue to be assessed through the next several months, it is all but certain that standing water and saturated soils in the wake of the storm will have a significant impact on harvesting efforts across much of the state through the upcoming weeks," the climatologist says.

What about the upcoming months? Grymes says early signals suggest that most of us along the Gulf Coast should keep our umbrellas handy. An El Niño (indicated by warmer-than-normal waters in the equatorial Pacific Ocean) appears to be brewing.

Although preliminary indications remain somewhat "cloudy" (pun intended, Grymes says), long-range projections from the National Weather Service Climate Prediction Center (www.cpc.ncep.noaa.gov/ ) as of early October indicate a likelihood for a cool and wet winter and spring for the Pelican State.

Such a long-range outlook comes as no surprise given the developing El Niño. History tells us that chances are better than two in three that southern parishes can expect wetter-than-normal weather during the winter and spring when El Niño is present. What the forecasts can't tell us is how cool and how wet. Mother Nature likes to keep that secret to herself.

"Thanks, Mother Nature!" Grymes says. 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.


On the Internet: LSU AgCenter: www.lsuagcenter.com/
On the Internet: U.S. Drought Monitor: www.drought.unl.edu/dm/
On the Internet: National Weather Service Climate Prediction Center: www.cpc.ncep.noaa.gov/
Source: Jay Grymes (225) 578-6870, or JGrymes@agcenter.lsu.edu 

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