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It’s the last week of September, with summer in the rear-view mirror, the fall foliage not yet turned much, and the walk-up to winter wondering soon to begin. So, it’s time to clean out the summer notebook.
One item that’s kept getting bumped by more urgent weather is the second in the “Focus” series, taking a deep dive into climate and weather for a single locale in Cardinal News territory. In May we started with a “Focus on Danville” column; today, the second in the intermittent series is “Focus on Wytheville.” Much of today’s column will focus on the historic weather of a town at an unusual crossing of interstate highways and, quite often, at the crossroads of weather in our regions.
But there was also an interesting weekend weather event that, at once, turned out largely like discussed here last week in terms of regional impacts, but not so much in its evolution. So, we’ll also take a quick look back at Tropical Storm Ophelia in the second section of this column.
Let’s jump in.
Focus on Wytheville
For nine miles in Wythe County, the northbound route of one interstate shares the same lanes as the southbound route of another interstate. Across the median, the opposite directions of those interstates also share lanes. (The two interstates, though labeled north/south, are actually tracking west-east for those nine miles.)
The rare “wrong-way” concurrency of Interstates 81 and 77 that passes through Wytheville is an apt metaphor for the town’s location in respect to the air masses that often affect our region.
Wytheville can be north or south, west or east, higher elevation or lower elevation, downslope or upslope, relative to whatever is going on with the weather in Southwest and Southside Virginia.
Wytheville is a town of about 8,000 founded in 1789 and named for George Wythe, a signer of the Declaration of Independence, also the namesake of surrounding Wythe County. It was a site of repeated action in the Civil War and the birthplace of first lady Edith Bolling Wilson, second wife of Woodrow Wilson, who himself was born at Staunton, 152 miles up modern-day I-81. Many travelers know Wytheville as a stopping point where I-81 and I-77 crisscross – and share the road for nine miles – and it is centrally located among regional outdoor and tourist destinations like the New River Trail, Grayson Highlands State Park, Mount Rogers National Recreation Area, and the Big Walker Lookout Tower some snaky miles west on U.S. 52.
Though there are some data gaps, a co-op station listed as 1 mile south of Wytheville has a respectable amount of weather reporting data going back to 1930 – pretty similar in completeness to those that exist for the same period at the major climate stations in Blacksburg and Danville. (There is also a patch of records from 1894 to 1905. Unless otherwise noted, “on record” for Wytheville will be the continuous data run since 1930.)
Some historic weather facts:
· Since 1930, Wytheville has not recorded a 100-degree day, peaking at 98 on July 16 and 17, 1988; August 14, 1998; and June 30, 2012.
· Like many locations in our region, the Arctic outbreak of January 1985 brought Wytheville’s coldest temperature on record, with a low of -20 on Jan. 21. The temperature that day never got above zero, with a high of -3, the only entirely subzero day on record since 1930 at Wytheville.
· Wytheville’s largest single-event snowfall is 24.8 inches, which came when many other stations in the region also had their largest or nearly largest snowfall, Jan. 6-7, 1996. Other top-ranking snowfalls are also at common timeframes with other stations in the region – the next two on the list are 18 inches on March 12-14, 1993 (the “Superstorm” or “Blizzard of ’93”) and 17.4 inches on Dec. 9-10, 2018 (our region’s last widespread “big one”).
Unfortunately, seasonal snowfall records are pretty porous, with lots of missing data. Long-term averages with available data show around 18-20 inches of snowfall for the season, depending on how it is sorted, but the reality is probably a little higher. Available data shows 60 inches in 1894-95 (part of that patch of late 1800s records), with 59.3 inches in the 1986-87 winter and 58.4 in 1995-96 close behind, both big winters across our region. However, only 13.5 inches of snow is shown for 1959-60, a huge red flag for voluminous missing data in an epic winter for our region.
Wytheville collected 48.9 inches in the 2009-10 winter, the biggest winter of the 21st century so far for most of our region except parts of Southside, which fits squarely between the 43.1 inches at Roanoke and 53.6 at Blacksburg. That’s often where Wytheville ends up in seasonal snowfall and in many individual snowfall events – similar elevation to Blacksburg and over 1,000 feet above Roanoke, but farther south than either of them, so sometimes more susceptible to mixed precipitation changeovers encroaching from the south.
This past winter’s 0.8 inch of snowfall appears to be the least on record for Wytheville – only the 1972-73 winter is shown with less, at 0.5, but it has 29 days of missing data and, while a below-normal snowfall year regionally, wasn’t such an extremely low-snow winter elsewhere in our region.
Here are five factors that affect Wytheville uniquely compared to many other locations across Southwest and Southside Virginia.
1. Rain-shadowed from both sides
Wytheville rests in a valley with Appalachian ridges rising both to the northwest and southeast. Downslope flow over these ridges tends to dry out rain bands, which can partially shield Wytheville from heavier rainfall, especially that which blows in from the southeast off the warm Atlantic water, condensing more heavily on the eastern edge of the Blue Ridge about 30-40 miles to Wytheville’s east. There can be a similar effect on systems moving in from the northwest, which generally have less moisture and can dry up entirely moving southeast over the Appalachians.
This is reflected in Wytheville’s annual average rainfall total, which since 1930 is just shy of 38 inches. Many locations in our region such as Roanoke, Lynchburg, Danville and Blacksburg average over 40 inches of rain. The slight rain-shadow discount on several systems throughout the year adds up to a few inches less in annual average rainfall.
Wytheville has never recorded a single-calendar-date rainfall above 5 inches in its entire recorded weather history. By comparison, Roanoke has had eight such dates and Lynchburg seven.
The double rain shadows, however, didn’t stop Wytheville from joining many other locations in our region with a record wet 2020, totaling 65.31 inches for the year.
2. Where wedge meets sticky
Wytheville often occupies a key pivot point near where a wedge of cooler air slides down the eastern side of the Appalachians and warmer, more moist air remains to the west and southwest.
This can be a flash point for severe thunderstorm development. In an extreme example, warm air overtook Wytheville on April 8, 2011, as temperatures shot into the 70s, while cooler air remained wedged in farther north, with Roanoke stalling in the 50s. One storm following the boundary between warm and cool developed rotation and produced the tornado at Pulaski, 22 miles up I-81 from Wytheville, that damaged over 300 homes and caused $5 million in damage.
(No tornadoes have been reported in Wythe County since 1950. Wytheville, however, did suffer a particularly intense hailstorm on May 6, 2022).
Wytheville can also be a dividing line between wintry precipitation to the east and rain to the west in these particular setups (while other setups reverse this – see the next section). This happened this past March 12 when cold rain fell over much of Southwest Virginia west of I-77 but became snow to the east, providing the only meager accumulation of the season for many locations, with Wytheville near the dividing line.
3. Where Artic air hits a speed bump
Flipping the scenario of the previous section, quite often Arctic air pools west of the Interstate 77 corridor, while dragging its heels pressing eastward over the mountains.
The spine of the Appalachians often acts as a speed bump to Arctic air masses arriving from the west and northwest. As a result, there have been a number of precipitation events over the years that have turned to snow from Wytheville westward while staying rain, entirely or at least for a longer time, eastward.
One extreme example of this was the 1950 Appalachian Storm, with Wytheville located about where the foot-plus totals started heading westward all the way into eastern Kentucky and southern Ohio. Wytheville measured 14 inches in that day-after-Thanksgiving winter storm that became so wrapped up the cold air was heading northeast across the Mid-Atlantic and warm air off the Atlantic eventually wrapped around its north side into Michigan. Snow of half a foot got as far east as Roanoke but dropped to nothing not far eastward.
Early April 1987 (10 inches in Wytheville ) and late January 1998 (11 inches) brought similar snow setups where Wytheville was the gateway to bigger amounts, deepening westward in the Arctic cold and dwindling eastward where milder air streamed in. More recently, Christmas Eve 2020 brought 4 inches to Wytheville as rain changed to snow from the west, with some heavier amounts westward while dwindling down to an inch by the time you got to Roanoke and very little eastward.
4. Upslope snow squalls
It might seem a bit contradictory considering Wytheville has already been mentioned as being in a downslope rain shadow from the northwest, but upslope snow bands lifting over the Appalachians from West Virginia on northwest winds behind Arctic cold fronts frequently reach Wytheville and sometimes leave an inch or two before withering just to the east.
Quite often during northwest wind flow behind a winter cold front, a particularly persistent and intense, but narrow, band of heavy snow develops just south of Wytheville, crossing Interstate 81 near Rural Retreat. Travelers heading either direction on the interstate can often be quite flummoxed, being in blinding snow one minute and in bright sunshine the next.
5. Higher elevation valley
Most of Wytheville is about 2,300 feet above sea level, give or take a hundred or two, yet it’s positioned between much taller mountain ridges both to the northwest and southeast.
Being, at once, in a higher elevation and in a valley contributes to Wytheville’s lack of 100-degree heat historically, and usually it is a few degrees cooler in summer than many locations to the south and east.
Wytheville is high enough it often gets into wintry precipitation when lower elevations like the floor of the Roanoke Valley and areas east of the Blue Ridge are stuck in cold rain. But it is also low enough that Wytheville ends up in the cold rain when snow is licking the 3,500+ ridges west and south of its location.
Recall last Feb. 12 when the season’s best shot at a widespread winter storm didn’t have much cold air to work with. An upper-level low passed over with a cold bubble, allowing snow to reach as low as about 2,700 feet in elevation – but not quite down to Wytheville.
So, when a forecast mentions something occurring in “higher elevations,” Wytheville is often on the bubble, between and betwixt as it is in so many other ways related to weather.
Wrap-up of Ophelia
A week ago here, we discussed how Ophelia would more likely be a cold-season-like baroclinic (forming along an air mass boundary), coastal low-pressure system, possibly with some hybrid tropical system elements, rather than become a purely tropical system. At that time, the National Hurricane Center gave it only a 30 percent chance of developing into a tropical cyclone.
But the scene had shifted by Thursday evening, as new information indicated the storm would get its center of circulation squarely over some warm water in the Gulf Stream that flows northward about 150 miles off the southeast U.S. coast, and that would allow the storm center to get fully rooted in the evaporation and condensation of that warm ocean water and develop a tropical circulation. It developed as a more conventional surface low-pressure system along a frontal boundary and contained hybrid elements throughout its evolution, but there was no doubting it had a warm-core tropical center by late Friday.
So that is how what was originally projected as a coastal storm or possibly a hybrid “subtropical” storm became Tropical Storm Ophelia, making landfall in North Carolain with estimated sustained winds of 70 mph, only 5 mph short of hurricane status.
For sensible weather in Southwest and Southside Virginia, the storm being a coastal baroclinic low, subtropical hybrid low or tropical cyclone mattered little.
We ended up with the expected heavier rain of an inch-plus along and east of the U.S. 29 corridor (the highway that connects Danville, Lynchburg, Amherst and Charlottesville), middling amounts mostly 1/4 to 1 inch but locally up to 2 inches as far west as the Blue Ridge, and trailing off to lesser amounts across the New River Valley and along and west of the I-77 corridor. (Quite fittingly for the subject of the first part of this column, Wytheville was about where the rainfall amounts started diving off the cliff to only a few hundredths.)
While forecasts for rain and wind didn’t change much for Southwest and Southside Virigina with this storm’s shift to a more tropical nature, it is important, moving forward toward a winter that will probably have more storms threatening wintry precipitation than last winter did, to note the importance of following a storm’s evolution as we get closer to its time of impact.
While I will always strive to discuss the most recent information I can about an upcoming storm system here in the regular Wednesday column that is linked in the weekly Cardinal Weather newsletter, this covers the current thinking during a narrow midweek window of time that may precede storm arrival by multiple days. Storm track forecasts can shift hundreds of miles and intensity expectations can increase or decrease dramatically in the space of 24-48 hours, let alone precipitation type projections in winter.
In this case, for a change of storm evolution even with little change in expected impacts, I followed up with newer information on Cardinal News for Thursday night, and also kept updating my social media channels — @KevinMyattWx on X/Twitter and Kevin Myatt’s Weather Wonders on Facebook – with updates.
The Cardinal Weather newsletter comes out once a week on Wednesday evneing, but any additional weather articles through the week are linked to the daily Cardinal newsletter and on the Cardinal News web page. (All free, no paywalls, but donations and sponsorships warmly accepted).
The coastal low/subtropical/tropical saga of Ophelia may have seemed familiar. As it turns out, there was a very similar setup back on Memorial Day weekend, a system that was mostly a coastal low but flirted with tropical potential, back when the offshore waters weren’t quite as hot. That ended up bringing heavy rain to locations from the Roanoke Valley southward, sort of setting up the summer pattern of wet southern Virginia systems leaving the northern half of Virginia dry.
It will be interesting to see in weeks ahead if coastal lows become a hard habit to break as we get into some colder weather. For now, no sequel of Ophelia in the coming weekend, which looks sunny and dry with cool mornings and warm afternoons.
Journalist Kevin Myatt has been writing about weather for 20 years. His weekly column, appearing on Wednesdays, is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.