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April showers bring May flowers, we’re told. But in many recent years, April showers have led to May torrents.
A disproportionate number of recent Mays have been among the wettest such months at multiple locations in Cardinal News country with more than a century of weather records.
It didn’t seem likely that this May would follow suit, following the infrequently and underwhelmingly showery trends of February through April, but two periods of rain last week have already pushed Danville to its 10th wettest May in over a century of local weather records with 6.99 inches.
Just east in Southside, South Boston’s co-op weather station data only goes back to 1972, but the 8.62 inches that has already fallen there this month would make this the third wettest May on record, even if nothing falls in the last nine days of the month.
It appears highly probable that there will be additional rain, likely substantial and possibly heavy, as a series of low-pressure systems and fronts affect Southwest and Southside Virginia over the Memorial Day weekend and into next week. It will be difficult to pinpoint exact times and locations when rain and potential thunderstorms will be occurring, which can be frustrating for the many outdoor activities planned, but there will likely be periods of rain and storms across our region intermittently starting Thursday and continuing through at least Memorial Day itself.
Both Danville and South Boston were included in the “abnormally dry” zone on the most recent U.S. Drought Monitor map based on data through May 13, but with two bouts of rain over the next five days totaling 3 to 7 inches — including a whopping 3.89 inches at South Boston recorded in the 24 hours through 8 a.m. on Thursday, May 15 — the yellow color for “abnormally dry” is likely to be erased over much of Southside and reduced to a few shreds elsewhere in our region when the new Drought Monitor map comes out on Thursday.
During the week before last, developing dryness, including briefly reaching moderate drought in Lee County, was washed out of Southwest areas of the state west of Interstate 77 by generous rains around May 7-9.
This leaves areas in between the Southwest corner and Southside — the Roanoke and New River valleys, up and down the Interstate 81 corridor and along and just east of the Blue Ridge — that had substantial but spottier rainfall last week. The yellow “abnormally dry” color may not be entirely erased here, but will almost certainly cover much less territory than it did a week ago.
A few spots got similar totals to those of Southside, but most got more moderate amounts, an inch or two, give or take some.
Unlike Danville, it appears unlikely at this juncture that Lynchburg, Roanoke and Blacksburg will follow suit with a high-ranking May for rainfall. But the 2-3 inches that has already fallen puts those locations well into contention, even with moderate amounts, for totaling near the 4-4.5 inches that is normal for the month of May, which would be a departure from the dry tendencies of February through April.
At Lynchburg and Roanoke, five of the 10 wettest Mays on record have occurred since 2003. Half of the wettest Mays have occurred in less than 20 percent of the period of record, dating to 1892 at Lynchburg and 1912 at Roanoke. Blacksburg is similar, with four of the 10 wettest Mays, and seven of the 20 wettest, since 2001 in data that goes back to 1893.
Roanoke’s wettest May was in 2020, with 11.44 inches of rain, and its fourth wettest was in 2018 with 9.5 inches. Three of Lynchburg’s 10 wettest Mays occurred in the consecutive years of 2016, 2017 and 2018, the last of which was the third wettest May on record in the Hill City with 8.32 inches. Many locations in our region had their wettest years on record in either 2018 or 2020, with May being a significant contributor to those watermarks.
It would take a far more rigorous study to establish the statistical significance (or lack thereof) of May seemingly trending wetter in recent years regionally, especially in comparison to most other months of the year that either don’t appear to be trending wetter or are doing so at a lesser rate. Denser moisture advection off warmer oceans, earlier subtropical/tropical influence, and the tendency for more fronts and upper-level lows to become stalled in more sluggish high-level flow could be some broader climate influences for an increase in May rainfall regionally as the planet has warmed.
This particular May has trended wetter than how it began and previous months in 2024, as storm systems that had been mostly tracking north and west of our region have dipped a bit farther south. You may perceive that as good news for your dusty garden or bad news interfering with outdoor plans on this Memorial Day weekend.
Heat is on?
In between the rainy spells, skies have been sunny with gradually rising temperatures early this week. A spike of heat with widespread 80s and some lower 90s possible is expected for this Wednesday afternoon as this column posts, with similar heat possible on Thursday before shower chances increase.
Extreme heat has pooled over Central America underneath a “heat dome” high pressure system much like we expect more over the U.S. during the summer months. Much as the high positioned west and south of us can do for our region in midsummer, the location of the high steered a powerful complex of storms across the Houston metro area last week, then across the northern Gulf of Mexico all the way to Florida, garnering an official “derecho” label from the National Weather Service.
The coming rainy period will break a short burst of drier heat in our region in favor of more warm stickiness. How hot it gets this summer locally will ride on whether or not we get under the sunny, dry heat domes for any extended period of time, if we stay more in sticky storminess, or if the heat dome parks far enough west to flush out our heat and stickiness often with cooler, drier air from Canada.
Next week, we’ll begin taking entries from readers for the summer heat prediction contest, aimed at guessing the highest temperatures at a couple of locations across our region. We’ll take entries for a couple of weeks for the hottest temperatures in the June 15-Aug. 31 period.
So start thinking about how hot you think it might get this summer in our backyard.
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.
