Wild and Wooly Pattern
The last two weeks of July have featured a rash of flash flooding thunderstorms here in the Tri-State area. From Olive Hill to Danville and from Lake Vesuvius to Sutton and Elkhorn City, violent thunderstorms crossed the WSAZ viewing area while I was away on vacation.
Conductor Dan Conley sent along the enclosed e-picture of felled trees along the railroad tracks in Wayne from Sunday’s downburst. There the sheer force of the wind driven rain proved too much for many trees to handle.
Of course our WSAZ weather team had the storms covered like a blanket. The efforts of Chris, Marina and Josh showcased the talent we have in our weather lab.
The nature of these storms is thermodynamic. That’s Greek to most! But let’s break it down using some old fashioned Language Arts from Ms. Fulmer’s 8TH grade class at St Matt’s elementary school in Philly (where I received a marvelous primary school education).
Thermo is the root for heat and dynamic means energy. When the air gets hot and humid, there is plenty of heat available for thunderstorm development.
Now in itself, a hazy, hot and steamy day can produce a cloudburst in the afternoon and evening. Localized high water is a given on these days.
But watch out when you throw in some wind energy (aka dynamics). That’s kind of like an athlete O.D.’ing on steroids. His muscles get oversized and for a time he can do Herculean tasks. The analogy of course is that run of the mill downpours turn into monsoons which flood our streams, creek beds and even our cities.
Last week, starting Saturday July 17th, heat wave conditions were building into the nation’s breadbasket and channeling in our direction. But in itself a hot air mass can struggle to muster rain when moisture is scarce. Just ask the folks who live in Vegas or Phoenix. That’s where the humidity comes into play.
However when steamy jungle-like air gets entrained into the summer heat, towering afternoon cumulus clouds build heavenward replacing the sunny skies and mirages of a desert heat wave. In time, the clouds turn from chunks of cauliflower in appearance to dark pieces of broccoli. These are the thunderheads that will soon unleash their downpours.
Now back to the Greek derivation. The term dynamic in science and engineering refers to motion and the kinetic energy available when an object (or in our case, a parcel of air) is moving.
In meteorology, a summer day will often see light winds at ground level. But as we look at winds at higher altitudes, the winds will increase in strength. Where those winds hit their maximum, we designate those areas as jet streaks (small areas of faster winds).
These are the regions where the kinetic energy, the “dynamics” of the atmosphere, is most prone to stronger thunderstorms.
For the first half of July, that wind energy was oriented thru southern Canada, leaving much of the Midwest and Northeast storm free.
Then as we moved to the last two weeks of the month, those so called “jet stream winds” settled south to I-90, I-80 and finally I-64. Torrential rains swamped Milwaukee, Chicago, Olive Hill and Pikeville to name a few towns.
As for this week, we started out quiet on Monday as the north wind blew less humid and less hot air into the region. Afternoon highs made the mid 80s with dewpoints in the mid 60s, down from mid 90s and 70s respectively last week. The jet stream too has temporarily retreated back into Canada.
Now however, that jet is showing signs of swooping south again this week. Meanwhile waiting in the wings, the humid tropical air of summer is planning its next appearance in our region.
Where those two forces meet, a new wave of violent thunderstorms will break out. On this Monday night, the tropical air is producing violent storms in Nashville and Bowling Green, KY.
Right now our super computers seem to suggest the merger point will be in the parched and heat riddled Carolinas.
Here’s a look at a map that shows where the heaviest rains this week MAY FALL. I say may fall since in this summer of malcontent thunderstorms, it seems anyplace, anytime best describes the thundery shenanigans.