'Ring of Fire' Weather Pattern Brings Dangerous Heat, Severe Storms and Heavy Rain
Published: July 20, 2017
A ring of fire weather pattern is gripping the U.S. this week, resulting in dangerous heat and bouts of thunderstorms that may contain damaging wind gusts, hail, isolated tornadoes and heavy rain.
Though "ring of fire" isn't a formal weather term, it's sometimes used by meteorologists to describe a particular summertime weather pattern that sets up occasionally.
Here's how it works: Sinking air associated with a strong upper-level high-pressure system east of the Rockies leads to very hot temperatures near its core. Forming a ring around the high's clockwise flow are disturbances aloft that tap into moisture, resulting in bouts of storms near its periphery.
You can see the general setup for this week's ring of fire weather pattern in the graphic below.
Ring of Fire Weather Pattern
Here's what to expect.
The worst of the heat this week will grip areas from the central Plains into the mid-Mississippi Valley, parts of the South and mid-Atlantic states.
Excessive heat warnings and heat advisories have been issued by the National Weather Service in parts of the Midwest, South and East for a dangerous combination of hot temperatures and high humidity. This includes Kansas City and St. Louis, where heat index values are forecast to be 105 to 115 degrees each afternoon through Saturday.
(MAPS: Forecast High Temperatures)
Highs in the middle to the upper 90s and a few 100s will be common from South Dakota to Missouri to parts of the mid-Atlantic states and the South through late week. Heat index values of 100 to 110-plus degrees are likely during the afternoon hours.
Forecast Highs This Weekend
Overnight temperatures won't provide much relief, with lows only dipping into the middle and upper 70s in the lower Midwest and South. A few spots will not even dip below 80 degrees late this week.
Few daily record highs are forecast to be threatened since that bar is high now that we are in the climatological hottest time of year in most areas.
(MORE: July the Hottest Month in Most of the U.S.)
Cooler conditions will return to the Midwest and Plains by Sunday as the area of high pressure weakens. Temperatures will also retreat to near average in the mid-Atlantic by early next week.
Ring of Fire Storms
The periphery of the high will be the main focus for stormy activity late this week.
The northern Plains, upper Midwest and Great Lakes will have the highest chance for bouts of severe storms, with damaging winds, hail and isolated tornadoes, as disturbances ride through the northern side of the high-pressure system. Flash flooding could also be problematic in those regions due to the several bouts of storms rolling through.
(FORECAST: Severe Weather Takes Aim on Midwest)
Friday's Thunderstorm Forecast
Saturday's Thunderstorm Forecast
In the Southwest and Rockies, monsoonal moisture will continue to flow northward on the western periphery of the high. Those storms could result in more localized flash flooding.
(MORE: Threats From the Southwest Monsoon)
The Northeast, Gulf Coast and Southeast coast will also see isolated to scattered showers and storms at times through late week.
Rainfall Potential Through Friday
MORE: Hottest and Coldest Temperatures Recorded in All 50 States
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