Active weather across the Arklamiss region in 2008

2008 was quite an active year for weather across extreme Southeast Arkansas, Northeast Louisiana and Central and Southern Mississippi. A robust La Nina mode of the El Nino Southern Oscillation (ENSO)helped to bring periods of wet and very stormy weather to the region from the start of the year through May. By June the ENSO mode trended toward neutral and allowed for rather typical summertime conditions to take hold through early August with periods of heat being not too extreme. August and September were rather wet months for most of the region as the impact of several landfalling tropical systems was felt. By the start of the fall season the weather tended to dry out a bit and conditions turned abnormally cool, especially in November. The cool trend culminated in a round of snow for portions of Southern Mississippi in early December, although the latter half of December trended warmer and stormier.

Rainfall:
Fortunately, yearly precipitation at most reporting sites across the Arklamiss was either near normal or somewhat above normal. This was a pleasant contrast to 2007 when yearly rainfall was at near record low levels for many areas. The drought in 2007 actually extended back to 2005, so the relative wetness of 2008 effectively ended a three year drought in many areas. Still, there were many locations across the region (especially across Northeast Louisiana, Southwest Mississippi, and portions of eastern Mississippi) that experienced some rather dry stretches during 2008, which negatively impacted the growing season. Favorable tallies on rainfall ledgers at many sites were not met until the very end of 2008, thanks to a very wet December. A few notable statistics include: 11.51" of rain for August in Jackson setting the monthly record for the site, and also the wettest August and September on record at the Natchez Corps of Engineers rain gage (measuring 12.92" and 14.83", respectively).
The following table contains rainfall totals from 2008 for a selection of major reporting sites across the county warning area. Also shown are rainfall averages at each one of these sites for the last 25 years (unless otherwise noted).

Flooding:
Heavy rainfall and snowmelt well north of our region contributed to very high flows along the lower Mississippi River in the spring and early summer. Flooding along the Mississippi River in our region was observed during March and April, and river stages at many gages reached levels not seen since 1973. Mississippi River backwater flooding was aggravated by locally heavy rainfall periodically during this time, but mainly in the lower Yazoo River basin. Later in the year there was widespread flooding in Southeast Arkansas and Northeast Louisiana (and scattered flash flooding elsewhere) associated with the landfall of Hurricane Gustav. River flooding once again peaked in December as several systems brought heavy rainfall. During the latter period the Pearl River gage at Jackson measured nearly 32 feet, which was the highest level since 2004.

Temperatures:
2008 average temperatures across the region ended up generally near long term yearly averages in the region. Seasonal temperature trends revealed January to be colder than average, followed by a warm February, with temperatures from March through June quite close to average. July tended to be hotter than average although the region only had to put up with one widespread bout of readings at the century mark (lasting from 2 to 4 days). In contrast to July, August trended much cooler than average with the cool trend continuing through much of fall. December ended up the year with above average warmth to balance out the ledger.
The following table contains 2008 temperature averages and long term yearly temperature averages for selected sites across the forecast area. Temperature tendencies are much more dependant on specific instrument siting than precipitation tendencies. For that reason there is no "substitution" of datasets in this table and differing periods of record are noted.

Severe weather:
2008 featured an above-average amount of severe weather across the Arklamiss. A telling statistic was the 108 recorded tornadoes in the state of Mississippi, which breaks the previous record for the state of 99, set back in 2005. As stated in a previous press release, it is important to note a vast majority of these tornadoes were weaker EF0 and EF1s, which tended to be vastly under-reported prior to the early and mid 1990s. A majority of the tornadoes in the region occurred from January through May when the previously mentioned La Nina mode of ENSO worked to bring together a multitude of severe weather setups (which is generally typical of La Nina modes in the cool season in this region). September also featured quite a few tornadoes across the Arklamiss, mainly attributable to the landfall of Hurricane Gustav. The most notable severe weather events for 2008 in our region include, chronologically:

1. January 10th: Outbreak of tornadoes (including 3 EF3 tornadoes) moved across the lower Mississippi Valley. Main path of destruction spanned from just north of Vicksburg northeast through the Golden Triangle. A school in Caledonia received extensive damage but, fortunately, no fatalities occurred.

2. February 5th: A widespread and historic tornado outbreak occurred across the Tennessee Valley and portions of the Southeast. Over 50 fatalities resulted from this outbreak (although none in our County Warning Area). The Arklamiss region was spared the worst of the weather, although supercells producing extremely large hail and several tornadoes did affect portions of extreme Southeast Arkansas and Northern Mississippi.

3. April 4th: Extensive wind damage and several tornado touchdowns occurred down the axis of the Interstate 20 corridor. Damage was most extensive through portions of the populated metropolitan Jackson area, where EF2 damage was surveyed.

4. August 2nd and 3rd: A vigorous thunderstorm complex plowed south and southwest through the heart of the region overnight and produced widespread wind damage from wind gusts peaking up to 85 mph in some locations.

5. September 1st through September 3rd: Hurricane Gustav made landfall in southern Louisiana and the slowly decaying center of the system made a slow track northwest and then north over the course of a few days (just west of our region). The Arklamiss remained on the active eastern side of the landfalling system for the period, receiving combined blows from heavy rainfall, gusty winds and isolated tornadoes. Widespread wind damage was mainly limited to areas of extreme Southwest Mississippi and Northeast Louisiana (south of I-20) late on the first as the center passed just to the southwest. Periodic tornado occurrences associated with the eastern rainbands were more widespread, with a total of 26 tornado touchdowns surveyed inside the confines of the Jackson WFO County Warning Area. Fortunately, no major injuries or fatalities were reported in our region with this activity.

6. December 9th: Outbreak of severe weather produced 16 confirmed tornadoes in central Mississippi. Two of these tornadoes were strong (EF2),but fortunately no major injuries or fatalities were reported from this activity. The 16 tornadoes recorded in the region ranks as the second most ever recorded in Mississippi for the month of December.

Winter weather:
Finally, 2008 was not without occurrences of rare snowfall across the Arklamiss. Prior to this year, the occurrence of snow has been either very isolated or very light in our County Warning Area since 2002. The three main snow events for our region are listed below chronologically:

1. January 19th: A swath of moderate precipitation across the southern half of Mississippi changed over to snow in the early morning hours, although temperatures at the surface remained generally above freezing. Snow became locally heavy in many areas south of Interstate 20 for several hours with up to 4 or 5 inches being recorded in portions of Covington, Jefferson Davis and Jones counties. Snowfall amounts across the rest of Central and Southern Mississippi were mainly less than 3 inches.

2. March 7th and 8th: A developing low pressure system in the northern Gulf of Mexico helped to bring snow to northwestern portions of the area, mainly in the upper Arklamiss Delta locales. Observed amounts were as high as 4 to 6 inches in portions of northern Chicot and Bolivar Counties. Amounts elsewhere were generally much less.

3. December 11th: Although temperatures were once again mostly above freezing, a strong upper level low moved across and turned rain to snow across portions of Northeast Louisiana, as well as Central and Southern Mississippi. Many areas along and south of the I-20 corridor experienced at least a little sleet or snow, but measurable snow was mainly confined to a 60 to 70 mile wide corridor paralleling(but east) of the Natchez Trace. The heaviest snow fell near the Highway 84 corridor in South Central Mississippi between Brookhaven and Prentiss, where amounts from 6 to 10 inches were observed. Amounts from 2 to 5 inches were more common elsewhere within the main snow swath.