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Amid all the headlines about heat waves around the nation and globe, a resident under the Cardinal News umbrella in Southwest and Southside Virginia may be thinking: “It’s really not been all that bad here.”
Your feeling that summer around here has not been all that hot so far is backed up by statistics. The average temperature for June 1 (when summer begins for meteorological record-keeping) to July 24 is the coolest for that period in 14 years at Roanoke, Lynchburg, Blacksburg, Bristol and Wytheville; coolest in 20 years at Danville and Martinsville; coolest in 44 years at Burke’s Garden; coolest in 49 years at Wise; and coolest in 51 years at Lexington.
Many locations in our region fell short of the 80-degree mark on Saturday. In this particular year, July 22 had similar afternoon temperatures to those of Feb. 23.
But it’s a long way until fall – still more than five weeks even until the meteorological data-defined autumn begins Sept. 1 – and our region has been floating on a small bubble of relative cool amid a vast sea of extraordinary warmth. It’s doubtful this summer will end up among the warmest few on record at many Virginia locales, even though it almost certainly will do so nationally and globally, but there is plenty of time and potential left for it to sizzle a few or several days.
With that in mind, the “heat dome” high that has been roasting much of Texas and the Southwest U.S. in heat even more extreme and persistent than is typical there is expanding eastward to affect a much larger portion of the nation for the remainder of this week.
A push into the mid- to upper-90s, possibly scraping 100 at some spots, is expected by Thursday through Saturday for the sub-2,000-foot elevation areas of our region – the Roanoke Valley and areas east of the Blue Ridge. (Heat index values, which we discussed here earlier this summer, may well go over 100). Many upper 80s to lower 90s highs are expected in the New River Valley and much of the region west of the Blue Ridge, excluding the highest ridges that often struggle to make 80 in even our worst heat waves.
With the main center of hot high pressure staying west, we will still be on the east side of the clockwise flow, and that will bring a new cold front southeastward by the weekend and early next week with increased storm chances and then a retreat of temperatures back to more season-normal 80s to near 90 for highs. Also, afternoon heating with sticky dew points, terrain effects and the occasional upper-level impulse may boil up some scattered showers and storms on some of our hotter days to mitigate the heat (though not the stickiness) in localized areas.
Early returns on forecast models suggest the same northwest flow out of Canada around low-pressure troughing to our north that we’ve seen much of the summer will truncate this round of higher heat for our region, though it will persist in states south and west of us. The heat to our west and south may well lash us again deeper in August.
For now, patterns of circulation favor keeping the worst of the Canadian wildfire smoke well to our north as the days heat up this week. Northwest flow next week might bring more of it southward.
Having a summer that has not yet pushed the mercury more to the top end of the thermometer in our region is not really a surprise when an El Niño pattern has developed in the equatorial Pacific Ocean. El Niño refers to irregularly recurring warm sea-surface temperatures in a narrow stripe from Peru westward into the open Pacific.
Twice in this space previously, on June 14 with a discussion of what El Niño may mean for Virginia and on July 5 in making some predictions for the second half of 2023 (one of those being few if any 100-degree days this summer in our region, a prediction in some jeopardy), we have discussed how El Niño summers are rarely among the hottest for our particular region, even though El Niño is known to inject considerable heat into the global circulation pattern. It is usually the case, and has been so far this summer, that the high-pressure ridges with the hottest air set up elsewhere during El Niño patterns, not over our region.
But we should be hesitant about concluding automatically that the rest of summer will necessarily follow the mild manner of previous weeks, given some historic examples.
Neither 1983 nor 2007 were especially hot summers up until this time of July, but both provided sizzling August weather with multiple 100-degree days. August 1983, an El Niño summer, saw a quick but extreme run of heat around Aug. 20 with Danville and Roanoke each hitting 105 degrees on one day each, even 99s at places like Abingdon and Blacksburg. August 2007 saw a much more prolonged heat wave lasting most of the month, with widespread 90s on many days and 100-plus on four days at Roanoke, five days at Danville, and peak temperatures of 106 at Clarksville and 108 at the John H. Kerr Dam, both in Mecklenburg County.
As for the overall global climate picture, cooler temperatures relative to normal in our region so far this summer really change nothing, as we have been no more than a slightly bluish pixel on a glowing-red wide-screen global monitor. It was still a record warm June globally when temperatures were below normal in our region, July will likely rank at or near the top also considering large expanses of hot land and sea temperatures compared to historic norms, and 2023 is still on track to be the hottest or nearly the hottest year on record globally – and actually could still be among the top few locally, given the warm winter months we had.
Even as we get a splash of the broader heat wave later this week, be thankful for the regional reprieve from extreme heat we have had most of this summer and may well have again entering August.
It is time to start paying attention to the Atlantic Ocean basin (includes the Gulf of Mexico and Caribbean) for possible tropical trouble.
The National Hurricane Center has been monitoring three systems, none of which are given high chances of developing into tropical cyclones over the next seven days. As of Wednesday morning, only the system farthest east was still being given a chance at developing into a tropical cyclone, albeit a slim one, though that could pose some risk to the U.S. by late next weekend.
Hurricane forecasters have been a bit flummoxed between the typical El Niño tendency for a somewhat dampened Atlantic hurricane season, owing to strong westerly flow aloft off the Pacific Ocean that often shears out developing tropical systems, and many regions of extremely warm sea-surface temperatures being observed across the basin (including a possible world record 101.1-degree F sea surface temperature off the south Florida coast), which could add fuel for tropical development.
Forecasters at Colorado State (it may seem odd, but one of the leading university tropical research centers is in Fort Collins, Colorado) have increased their forecast for the season, from an initial forecast of 15 named storms and seven hurricanes to a new projection of 18 named storms and nine hurricanes for the Atlantic basin, based primarily on the widespread extremely warm sea-surface temperatures.
A storm is given a name when it becomes a tropical storm with 39 mph sustained winds around a closed circulation center fed by the latent heat released in evaporated ocean water. There have already been four named storms in the Atlantic, including one hurricane, Don, which affected open water very far to the north of what is common in July.
Both greenhouse-gas-related climate change and a reduction of sun-blocking aerosols from ship exhaust, along with coinciding natural atmospheric patterns over the ocean this particular summer, have been noted as likely culprits for the warm Atlantic water temperatures, not typically something that happens during El Niño, which is a warming of the equatorial Pacific.
Be that as it may, and however the conundrum between shearing El Niño winds and warm sea surface temperatures plays out, August is historically when we should start paying more attention to tropical systems in the Atlantic, both for any coastal plans we may have and for any potential impacts inland in our region. Unless other more urgent weather intervenes, we’ll revisit this matter more in depth in this space next week.
Heat contest update
Between the time contest entries are sent in and the time to score them to find the winner, I rarely look at them. So I can’t really tell how individual entries in the heat prediction contest are doing compared to the whole. But if you remember what location and temperature you entered when you emailed me last month, here is an update on how you are doing, so far. (Closest guess wins, with earliest entry being tiebreaker if two or more picks are equal.)
Listed is the highest temperature, as of Tuesday, July 25, for each station since the contest period started on June 20, with a big possibility that many of these are topped in the next several days.
Abingdon 87, Appomattox 91, Blacksburg 87, Clarksville 95, Danville 91, Galax 86, Lexington 90, Lynchburg 92, Martinsville 91, Roanoke 94, Wise 86, Wytheville 87.
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.