Midsummer-like heat strikes back, but its days are numbered

August has tried to play it cool, but this summer’s hot and dry habit is hard to break.

Last week brought widespread anomalous late August chill and even some record-setting cool temperatures to the Southwest and Southside Virginia coverage area of Cardinal News. We recapped several of the lows on the morning of Wednesday, Aug. 21, in the article linked here , but Thursday and Friday, Aug. 22 and 23, brought additional cool regional morning lows ranging from the upper 30s to the lower 50s. Some notable examples:

• Danville tied a 102-year-old record Aug. 22 low at 51 degrees, then tied a 99-year-old record Aug. 23 low at 53 degrees.

• Roanoke had its two coolest back-to-back August mornings in 35 years with a pair of 50s.

• Tazewell County icebox Burke’s Garden recorded a low of 38 on three consecutive days, its coldest three-day stretch of August morning lows in 35 years.

• Abingdon followed up 47 on Aug. 21 with 46 on Aug. 22, the coldest two-day stretch of August low temperatures in 20 years.

• The Aug. 22 low of 41 at Copper Hill in Floyd County was the coldest August temperature recorded at the co-op station since it began reporting in 2000.

But the sizzle of mid-July has returned for a few days this week. Many areas in the lower elevations of our region topped 90 on Tuesday. As this Cardinal Weather column posts Wednesday afternoon, several locations across our region are expected to see their hottest temperatures since July 16, with mid to upper 90s in the Roanoke Valley and east of the Blue Ridge, and even topping 90 in much of the New River Valley and some lower-elevation valleys of Southwest Virginia.

It would not be bizarre if a spot or two clipped the 100-degree mark somewhere in Central or Southside Virginia on this Wednesday afternoon.

But this week’s heat surge is not midsummer-like heat setting up for a long stay, just as last week’s morning chill wasn’t autumn setting in for good. (Some called it a “false fall.” I prefer “fall preview,” since it’s never going to be real fall in August, anyway.)

A deep jet-stream trough that brought cool, dry weather last week shifted away from the eastern U.S., allowing the heat dome high-pressure system over the south-central U.S. to balloon north and east and include us in its hot, dry air for a few days.

The common denominator between the two air masses is the word “dry.” By mid-July, most of our region was in moderate to severe drought, but those conditions improved substantially across most of our region in the latter half of July and especially the first half of August.

(As of the Aug. 22 issuance of the U.S. Drought Monitor, moderate drought lingers in parts of the New River Valley and Southwest Virginia in and around Tazewell County. Drought remains severe in some of the Shenandoah Valley north of our region. The latest U.S. Drought Monitor for Virginia, due to update on Thursday, is linked here. )

But now, we are nearly three weeks past the pour of Tropical Storm Debby that affected all but the western counties of Cardinal News’ Southwest and Southside Virginia coverage area, and almost two weeks past a more streaky but fairly significant rain that wetted most of the southern half of our region.

The good news for both the hot and dry situations is that a southerly dip in the jet stream over the central and eastern U.S. is re-establishing, and that will bring cooler, wetter weather over the next several days.

This won’t happen with a sudden shift. Thursday will be almost as hot as Wednesday, and might feel worse, as dew points climb with thickening moisture in the air. But a slow-moving cold front pressing south and east will increase the chance of showers and thunderstorms throughout the late week and weekend.

That might not be the best news for Friday night high school football or Labor Day weekend outdoor plans, but none of these days are likely to be constant widespread washouts. Some early projections suggest that rain totals may exceed an inch over much of our region through Sunday, but not all at once. That would be helpful in heading off any renewed sliding toward deeper drought.

Labor Day itself looks to dry out behind a cold front with seasonable temperatures, 70s highs in the mountains to 80s in lower elevations. Even cooler air may return after that into the middle to latter part of next week, possibly more 40s lows and widespread 60s-70s highs.

Perhaps we will have to decide again down the road if it’s another “false fall” or a “fall preview,” or maybe even the first strained effort at “real fall.”

Hurricane season underachieving?

We are moving toward the statistical peak of Atlantic hurricane season over the next three weeks, but there is some buzz about how relatively unimpressive this season has been, at least compared to forecasts, especially now with a late August lull of several days since Hurricane Ernesto buzzed Bermuda. There is presently a region of the Atlantic being monitored for possible tropical development over the next week or so.

Five named storms by the end of August is a decent number, but there are growing doubts that the 2024 Atlantic hurricane season will be able to realize many expert forecasts that leaned toward a highly active season.

NOAA, the federal agency overseeing several weather forecast units, has projected 17 to 25 named storms, with 8 to 13 hurricanes and four to seven major hurricanes , noting 70% confidence in this prediction. Similarly, the Colorado State University Tropical Weather and Climate Research unit projected 23 named storms, 12 hurricanes and six major hurricanes . And a University of Pennsylvania climate research team led by well-known climate researcher Michael Mann has projected 33 named storms , which would be a seasonal record in the Atlantic.

One factor that may be at play in the somewhat lagging tropical season is that La Niña, the irregularly recurring cooling of equatorial Pacific sea surface temperatures, has stumbled out of the gate and hasn’t really developed yet. La Niña is strongly correlated with an increased number of tropical systems in the Atlantic, presumably because high-level westerlies off the Pacific do not shred the tops off developing systems as frequently in La Niña as would happen in its warm-water cousin, El Niño.

(Our region’s snow fans should be rooting for La Niña not fully developing, or reaching only a “weak” level, by the winter ahead.)

Large tropical development-suppressing dust storms blowing off the African Sahara over the Atlantic Ocean, cooling waters in some sections of what had been an extremely warm Atlantic Ocean, and just some happenstance with how and when disturbances have been ejected off Africa into unfavorable atmospheric conditions over the Atlantic may play into it as well.

But it is important to note that there still is time for tropical development to play some catch-up, as September and early October are the core of the season. Hurricane Beryl has already made history as the earliest Category 5 hurricane in the Atlantic in recorded history, and as always, it would only take one extraordinary hurricane into a densely populated coastal area to make this a truly memorable season.

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. Sign up for his weekly newsletter:

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