Weather Journal: Recent extreme heat in May in Roanoke recalls more than 81 years ago | Local News

Say “1941” and the first thing that rightly comes to mind is America’s entry into World War II after the Japanese bombing of Pearl Harbor on December 7.

1941 has also cropped up lately, locally, as the opening year of The Roanoker restaurant, an establishment that closes this weekend.

Last weekend’s premature summer heat wave presented 1941 in a different light. Friday was tied for Roanoke’s hottest May Day since 1941, sharing that honor with also 96-degree May Days in 1962 and 2011. It hadn’t been hotter than Friday in May in 81 years. .

But hotter, longer was May 1941. There were six days of 95 degrees or more in Roanoke in May 1941, nearly half of the 14 May days recorded since 1912 and double the number of those days in 81 years since 1941.

Five of those six days were warmer than Friday.

The May 1941 heat wave peaked at 99 degrees on May 22, framed by 97-degree days on either side. After a brief cool break – it dipped to 43 for an early morning low on May 25 – the heat returned with a vengeance, hitting 98 on May 28 and 97 on May 29.

People also read…

The front page of the Roanoke Times for May 23, 1941 was dominated by war — “GUNS OF BRITISH NAVY DEFENDING CRETE; THE LUFTWAFFE CLAIMS VICTORY OVER THE FLEET,” misleads the main headline.

The second page, however, was highlighted by news of the heat wave and accompanying drought – “Mercury rising to record highs in the state; Dry Spell Damage Crops,” read the main title, draped across the top of the page.

The Associated Press article under the headline reported Danville hit 101, Lynchburg 100 and Roanoke 99 the previous day. Richmond recorded its hottest May day on record at 95.7, the article reports, but that would be surpassed by 97 the next day and 98 on May 28.

A household name that many today associate more with a minor league baseball park was guiding a New River Valley community through a drought. “Due to continued dry weather, Mayor EW Calfee yesterday called on Pulaskians to help conserve the municipal water supply by stopping all sprinkling and the use of hoses to wash floors and walkways.”

The heat temporarily ceased with storms accompanied by gusty dusty winds and large hail before a cold front on May 23, but returned a few days later with another banner title on May 29 focusing more on drought: “Drought Destroys Much of State’s Crops – Federal Aid Requested.” »

The article reported that 75% of the state’s hay crop had already been ‘burnt’ and that 20% of dairy farmers in the state were already giving hay to cows when they should normally be able to graze on pasture. .

If all this fuss over the oddly timed heat of 1941 sounds familiar, we also looked back to 1941 when temperatures soared into the mid-90s in early October 2019.

When Roanoke’s temperature reached 98 on October 3, 2019, it was the hottest October day since 1941, when it reached 99 on October 6 and four days reached 95 or more.

Two months before the Japanese attack on Pearl Harbor, there was a warmer October day in Roa…

Which brings us to a curious curiosity about 1941: there was extreme heat in May and October, unmatched in intensity and persistence in any of those months through the 110 years of daily weather records from Roanoke until to date, but the summer in between was pretty bland. .

In fact, during the meteorological summer of June 1 to August 31, Roanoke’s temperature never exceeded 97 – May 22 and October 6 were the hottest days of 1941 at 99 degrees.

The 1941 summer average temperature of 75 degrees is in the middle of the pack among the 110 recorded summers, just short of a long-term average that fell from 74 to 75.5 in just over a century.

This proves that extreme heat in May does not necessarily portend a similar event in summer.

May, like most months, has warmed on average over the past century locally, paralleling national and global trends primarily related to greenhouse gas emissions from human industrial activities. The sensor location shifting from a rural environment to a heavily commercial environment, inducing more “urban heat island” warming, is also a likely factor in warming Roanoke temperatures.

The average May temperature, using statistical regression with long-term data, rose half a degree in Roanoke from 64.9 to 65.4 over the past 110 years.

But a deeper dive into the data reveals that it’s not that simple.

May’s daily highs, the hottest on record each day, fell more than 2 degrees from 78.1 to 75.8, while the daily lows, the coolest on record each day, climbed further by 3 degrees, from 51.6 to 55.

May days have gotten cooler, May nights have gotten much warmer, locally in Roanoke, since 1912.

There’s a clue as to why that might be – in the same time frame, average May rainfall in Roanoke fell from 2.84 inches to 4.73 inches, again using statistical regression calculated by the National Weather Service.

Four of the wettest six Mays on record have occurred since 2000.

All of this data would imply that May has become a stickier, cloudier, and wetter month in most years than it has in the past. This kept daily highs from getting as hot while overnight lows were accentuated, a trend we saw strikingly throughout the hottest months of the year. Higher dew points, widely observed in other studies, due to advection from warmer oceans, are likely culprits.

This month of May has quickly shown both sides of the coin, going from hot and dry to cool and soggy in just a few days, with Roanoke having its first day of 2022 with more than 2 inches of rain on Monday as temperatures fell from record highs. tough heat to stay stuck in abnormally cool 50s and 60s all day through Wednesday.

Weather Journal appears on Wednesdays.

Contact Kevin Myatt at [email protected] Follow him on Twitter @kevinmyattwx.