The Russian heartland has reeled this summer under deadly severe heat thathas only been made worse by debilitating drought and wildfires.Moscow has its hottest month in 130 years of records, including its highesttemperature ever recorded.
Average temperatures for the month of July were fully 15 F above normal, andsince the start of summer, average temperatures have been a staggering 13.8 Fabove normal.
Fires are blazing where normally the land is lush and well-watered withgreen woods and crops.
The Associated Press reports that tens of thousands of firefighters andvolunteers were battling wildfires that have killed at least 40 people anddestroyed several thousand homes so far. Smoke from these fires has envelopedMoscow with smog.
Hundreds more have drowned in swimming mishaps while trying to cool off fromthe relentless heat.
So what exactly is the cause of this unusual, severe heat in an area usuallyaccustomed to moderate, moist summers?
"Clues can be found in the upper atmosphere of the middle latitudes, wherethe ever-present winds of the jet stream hold sway," said AccuWeather.comSenior Meteorologist Jim Andrews.
According to Andrews, a strong upper-atmospheric high, or ridge, built overEuropean Russia toward the beginning of summer. In doing so, it diverted thejet stream and its rain-giving train of summer storms farther north than usual,giving much of the area drought conditions this summer.
In addition, southern desert heat from central Asia, the Arabian Peninsulaand North Africa began to flow northward, which strengthened this ridge andtightened its hold over the region.
Land parched by drought normally tends to heat more than well-watered land,as evaporation works as a cooling agent, Andrews said.
"The land and the atmosphere above it answer by becoming hotter," he said.
"This, in turn, strengthens the upper ridge and its ability to shunt awaycooling, rain-bearing storms riding the steering winds of the jet stream."The increase in temperature, the increase in evaporation and the drying ofthe ground create a "vicious cycle" in that each condition continues tointensify, and it is unclear which condition came first, which Andrews refersto as a "chicken or the egg" conundrum.
Whatever the case, the cycle seems to have kicked in with profound effectfor millions in the Russian heartland.
So, what will it take to break the iron-clad upper ridge and the heat anddrought it has created?According to Andrews, this pattern will run its course eventually, as strongsunshine of long Russian summer days will inevitably give way as the seasonsprogress.
"Rain-giving storms will break down the ridge followed by the cold and snowof the long Russian winter," he said.
In the meantime, heat and drought will grip greater Moscow through at leastSunday with abnormal heat for at least another week in southern Russia.
Story by AccuWeather.com's Gina Cherundolo and Expert Senior Meteorologist JimAndrews
