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The preacher man says it’s the end of time, and the Mississippi River, she’s a-goin’ dry.“
This column, being “about weather and not much else” as promised in the first edition back on October 12, will not attempt to pronounce the near-term likelihood of the “end of time” in the opening line of Hank Williams Jr.’s 1982 signature song “A Country Boy Can Survive.”
But the Mississippi River has in fact, of late, been a-goin’ dry. At Memphis, the river level in October reached the lowest stage since modern era gauge records began in 1954 and, after some recovery in early November, is declining again. The lowered river level, while snarling barge traffic, has revealed a recently sunken casino boat, a ferry that sunk in 1915, and even an ancient lion fossil.
It is emblematic of a nation that is experiencing widespread dryness from long-term lack of rainfall. Last week’s U.S. Drought Monitor map shows nearly 82% of the land area of the 48 contiguous states in stages of dryness ranging from “abnormally dry” to “exceptional drought” with almost 62% in at least moderate drought. (If you click on this Drought Monitor hyperlink Thursday or later, a new week’s map will be posted. It likely won’t show hugely different percentages, maybe some improvement in the South.)
But bring the focus to Virginia, and not much more than a third of the state is considered “abnormally dry,” as of last week, and less than 2% (mostly the Eastern Shore) is suffering anything worse.
Focusing even tighter on Cardinal News territory, only a few counties at the eastern edge in Southside and four counties in the Southwest tip are “abnormally dry.”
Everything else in between is considered adequately hydrated, presently.
Indeed, Roanoke, before whatever rainfall fell Tuesday night and Wednesday morning, was already pretty much at its annual normal rainfall with a month left – 42.73 inches through Nov. 28 when 42.82 is the 1991-2020 normal for a calendar year. Lynchburg is getting close too – 41.21 inches through Nov. 28 when 42.76 is the annual norm. So is Blacksburg – 41.15 total through Nov. 28, 42.64 being the annual norm.
But then, there’s Danville, that is almost 6 inches below normal for the year to date (through Nov. 28) at 34.54 inches and is going to need truly inundating downpours in December to reach the annual norm of 43.73 inches.
It’s a little curious considering these statistics that Danville is just outside the “abnormally dry” zone on the Drought Monitor map, which paints most of Halifax, Charlotte and Appomattox counties (and the eastern fringe of Campbell County) yellow, and everything eastward to almost Hampton Roads. But perhaps Danville’s near-normal 3+ inches of rainfall so far in November has been enough to moisten the soils and raise stream levels sufficiently for the Drought Monitor to not consider it currently dry there.
The dryness in the southwest corner of Virginia is merely the eastern fringe of the more widespread and significant drought in much of the Ohio and Tennessee valleys. The southwest corner, as residents are fond to note, is indeed closer to the capitals of Kentucky, West Virginia and Ohio than it is to Richmond, and quite often, its weather hews more closely to those states than to the rest of Virginia.
We could spend a lot of time here dissecting why 82% of the nation is abnormally dry.
We are in the third year of a La Niña pattern, the cooling of equatorial sea surface temperatures in the Pacific, often linked to weaker flow of subtropical moisture across the southern half of the U.S. Large heat-dome high-pressure systems formed over the central U.S. this summer, translating west with time, suppressing rainfall and blocking storm systems over a wide region. And, of course, climatology studies have found droughts are becoming more common, more extreme and more extensive as the global average temperature warms, linked to increased greenhouse gases from human industrial activities.
The Mississippi River is only three years removed from a top-five high crest at Memphis. Likely, weather patterns will shift soon enough and high water will be rollin’ on the river again rather than it a-goin’ dry. Drought in parts of the West fueling rampant wildfires, allowing Lake Mead to give up its dead and threatening water supplies for farmers, ranchers and perhaps, eventually, some major cities seems to be a much more chronic concern.
But being focused on Southwest and Southside Virginia weather, our main job here is to figure out why our region, for the most part, is not experiencing that dryness, currently.
It comes down to atmospheric happenstance and geologic permanence (relative to human timescale): Tropical systems and upslope flow.
The most straightforward factor is that the large section of our region not in abnormal dryness was the most affected by the rain from former hurricanes Ian (Sept. 30-Oct. 2) and Nicole (Nov. 10-11).
It was a late-firing and not especially active Atlantic tropical season, but the two most significant U.S. landfalling storms just happened to track right across our region after landfall.
Ian left the southwest corner of the state dry and tended to be lighter in the more eastern parts of our region compared to all the places in the middle nearer the Blue Ridge where 2-4 inches was common. Does that sound a lot like the Drought Monitor map?
Nicole swept widespread inch-plus rainfall across our region, but its heaviest rain on the 3-5-inch side of things tended to be concentrated along the Blue Ridge.
Last week this column covered frequent upslope flow over the mountains from the northwest that often brings snow showers in winter. But upslope flow from the east and southeast against the Blue Ridge is a much more frequent, substantial factor for heavy rain in the localities along and nearest the sharp rise in terrain from Piedmont to Appalachians.
Ian and Nicole were not the only examples of upslope-enhanced moist flow against the Blue Ridge in recent months. Storm systems on August 15, Sept. 5 and Nov. 5 also had substantial easterly or southeasterly upslope flow components that brought heavier rain, often exceeding an inch, to locations near the Blue Ridge while little or even nothing fell in areas to the east and west.
In any event, Virginia is faring far, far better currently with moisture than it did the last time we were in the third consecutive year of La Niña. By autumn 2002, after a couple different waves of dryness since 1998 that shrunk reservoirs and dried up streams, 98% of the commonwealth was considered to be in moderate drought or above, with a bullseye of “exceptional drought” centered right on Southside, covering Danville and Martinsville. (El Niño soon reversed our precipitation fortunes.)
Coming off super-soaked years in 2018 and 2020 that set records for heaviest annual rainfall at many locations in our region, there was little chance this triple-dip La Niña would turn out nearly as bad with long-term drought as the one at the turn of the century.
We can be thankful that the James, Roanoke and New rivers aren’t the ones a-goin’ dry this go-round.
STATS OF THE WEEK
The main topic of today’s column is pretty statistic-heavy, so we’ll do something a little more fun in the stats of the week.
Cardinal News readers from Tazewell to Tidewater (and a few beyond the commonwealth) came forward with 245 entries in our first Cardinal Weather snowfall prediction contest, which deadlined on Black Friday. That’s about double the number that entered in the final contest I ran for The Roanoke Times last fall. Some 142 of these entries were from school groups, with 103 from emails sent to me.
Averaging out those 103 entries, each picking for two different sites, here are Cardinal Weather readers’ group-sourced total snowfall predictions for the 2022-23 winter: Bluefield, W.Va., 37 inches; Blacksburg, 24.6 inches; Danville 8.1 inches; Lynchburg, 12.9 inches; Roanoke, 17.8 inches; Tri-Cities Airport, Tenn., 14.5 inches.
There are significant atmospheric pattern shifts on the horizon that could start to make some of our wintry talk more relevant. But not yet.
Though Thursday will be on the cold side, the next week or so will continue to be mostly mild, 50s and 60s highs, 30s and 40s lows most days, with chances of rain every three or four days as Pacific-origin cold fronts push through west to east.
Starting about late next week, there are signals in long-range models that high pressure near Greenland will block the jet stream like a boulder in the stream and force it southward, bringing colder air into much of the central and eastern United States.
It is way too early to tell how or if specific moisture-bearing systems will interact with that cold air for snow or ice threats, but let’s just say – quoting a much different song than what we started this column with – it’s beginning to look a lot like Christmas.
Journalist Kevin Myatt has been writing about weather for 19 years. His weekly column is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.