Sunday, June 24, 2012

Mid-South drought continues to worsen, little relief in sight

As the typically hot summer season gets underway, the Mid-South continues to deal with a growing drought problem that unfortunately shows no sign of letting up anytime soon. Though parts of the area have received some helpful and significant rain in the last few weeks from passing storm events, rainfall deficits continue to generally increase, and the drought’s severity has begun to accelerate in response.

In the latest U.S. Drought Monitor dated June 19, the metro area now stands in “Moderate” to “Severe” drought conditions. Locally, the worst drought conditions exist in the Crittenden County area as well as the northwest Mississippi Delta. Severe drought conditions have also grown to include nearly all of Arkansas as well as northwest Tennessee. Southwest TN, the biggest beneficiary to some of our recent rains, fares slightly better under the moderate drought. Still, this marks a deterioration of conditions there too.

U.S. Drought Monitor as of June 19. Metro conditions range from "Moderate Drought" (tan) to "Severe Drought" (orange).
The drought continues to worsen thanks to persistent high pressure that has held tight over much of the area since early in the year. This high pressure area has usually kept the active conveyor belt of weather, or the jet stream, far removed from the area. Thus, a long-term wet weather pattern has been very hard to come by. As of June 23, Memphis’s rainfall deficit has grown to over a foot, at 12.43”. With a yearly rainfall total of just 14.70” recorded at the airport that represents just 54% of the average.  As the graphic below shows, much of the area needs anywhere from 9 to 13 inches of rain to end the ongoing drought, with even worse conditions to our north and west.

How much rainfall is needed to end the drought. Image courtesy of Beau Dodson/
As the situation worsens, so does the level of impacts to a variety of interests. Many area yards and plants are beginning to brown, requiring increasing amounts of daily watering.  For those in agriculture, the lacking rainfall and drying soil moisture may soon begin to damage crops and limit harvest potential. Flow levels in area rivers/streams continue to drop with some tributaries potentially drying up. The Mississippi River at Memphis is currently at -2.55 feet, though still well short of the record low of -10.7 feet set in the historic drought of 1988. Fire danger is also increasing. While no burn bans or water conservation measures have been enacted to this point in the metro, much of AR is under a burn ban and such actions may occur locally as the summer continues if conditions do not improve.

Unfortunately, it does not appear that the situation will improve soon. The short-term forecast (next 5-7 days) offers near zero rain chances as temperatures soar to the mid and even upper 90s. Long-term forecasts don’t offer much hope either with above normal temperatures and near to below normal precipitation over the next 1 to 3 months.  As such, the Climate Prediction Center indicates our drought persisting or intensifying through the end of September.

The seasonal drought outlook through September 30. Drought conditions are expected to persist or intensify.
In these situations it often takes the remnants of a tropical system moving through the area to break the drought. While Tropical Storm Debby did develop yesterday in the central Gulf of Mexico, its track remains very uncertain due to a wide range of solutions offered by computer models. Chances are that we would receive little if any rain from this storm no matter it's track given the intensity and persistence of high pressure overhead. We will continue to monitor Debby’s progress and let you know if that changes.

Latest track of Tropical Storm Debby, courtesy National Hurricane Center
Stay with MemphisWeather.Net for up-to-date information on our worsening drought, the summer heat, Tropical Storm Debby, and all things weather affecting the Memphis area and the region as a whole!

--Kevin Terry, MemphisWeather.Net

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