There's another side to the weather pattern of the past six weeks that brought late summer/early fall heavy rain and flooding to the western Midwest and Northern Plains. That other side is the onset of drought over the southeastern U.S. From the Ohio Valley south to the Gulf Coast and the south Atlantic coast, along with the central and southern two-thirds of Texas, hot and dry conditions have set in quickly.
Comparing the U.S. Drought Monitor's presentation Aug. 6 with the latest one, Oct. 1, some stark numbers show up. The southeastern U.S. Drought Monitor Aug. 6 showed 87% of the region with no drought -- zero -- none. On Oct. 1, that same region only logged 22% with zero drought. That amounts to a 65% decline in the non-drought area -- or, if you want, a 65% increase in the area with some phase of drought.
Put it another way -- only around 15% of the southeastern U.S. had some phase of drought going on back in early August. Now, in early October, almost 80% of the region is in some phase of drought; this is another occurrence of a flash drought.
As noted in a study titled "Flash Drought Characteristics Based on U.S. Drought Monitor" and published in the journal Atmosphere, a flash drought is defined as an event with greater than or equal to two categories degradation in a four-week period based on the U.S. Drought Monitor. The circumstances we see in the southeastern U.S. now, compared with just eight weeks ago, certainly bear that out.
The current situation details are here in the Drought Monitor summary for the Southeast from the Oct. 1, 2018 Drought Monitor:
The warm and dry pattern continued over the region, with temperatures for the week generally 9 to 12 degrees (Fahrenheit) above normal. Most of the region was dry with only small, isolated pockets of observed precipitation.
Many areas had their warmest and driest September on record, accelerating the drought conditions in the region with dryness going back eight to 10 weeks now with associated high temperatures. In areas from Virginia south into northern Florida, degradation was widespread, with many new areas of severe and extreme drought added.
Outside of coastal areas impacted by recent tropical weather, almost the entire region is abnormally dry or worse, with many areas seeing multiple class degradation over the last several weeks. New areas of extreme drought were added to Kentucky, Alabama, Georgia, and South Carolina.
Additional articles which covered the flash drought development and were posted Oct. 4 are included at the following links:
From the Tennessean: https://bit.ly/…
From Scientific American: https://bit.ly/…
Bryce Anderson can be reached at firstname.lastname@example.org
Follow him on Twitter @BAndersonDTN
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