Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 7:50 PM GMT on January 30, 2013
A powerful tornado ripped through Adairsville, Georgia, northwest of Atlanta, at 11:19 am EST this morning, killing at least one person in a mobile home park. The tornado caused major structural damage in the downtown district, and overturned approximately 100 cars on I-75 near Exit 306 (see eyewitness video here, with swear words.) Eight injuries, some serious, are also being reported from a tornado just southeast of Calhoun, GA around 11:30am EST. NOAA's Storm Prediction Center has placed most of the Southeast in their "Slight Risk" region for severe weather for Wednesday, a step down from the "Moderate Risk" potential issued on Tuesday for the Midwest. Three other tornadoes have hit Georgia today, and there were 79 reports of wind damage due to high winds as of 2 pm EST along the cold front that triggered today's severe weather, from Alabama to Pennsylvania. Tornado watches continue for a wide swath of the Southeast this afternoon, from Alabama to North Carolina.
Figure 1. Car overturned by the tornado near Adairsville, Georgia, on January 30, 2013. Image courtesy of WSB-TV on http://pic.twitter.com/2lAL0Lmc.
Figure 2. Radar reflectivity (top) and Doppler velocity (bottom) images of the tornado that hit Adairsville, Georgia at 11:19 am EST Wednesday, January 30, 2013. Adairsville is under the circle with a "+" in it.
Figure 3. A wild weather day in the Southeast: NOAA's Storm Prediction Center logged four preliminary reports of tornadoes as of 2 pm Wednesday, along with 79 reports of damaging winds.
Video 1. View of the Adairsville, Georgia tornado of January 30, 2013. Note the blue power flashes as the tornado brings down power lines.
Record string of 219 days without a tornado death ends
Today's fatality ends the longest continuous stretch without a tornado death ever recorded in the U.S.--219 days. The last time the U.S. saw a tornado death was at Venus in Highlands County, Florida, from an EF-0 tornado associated with Tropical Storm Debby on June 24, 2012. The previous record was 197 straight days without a tornado death, which ended on February 28, 1987. Part of the reason for the long stretch without a tornado death during 2012 - 2013 was the relative lack of tornadoes. According to NOAA's Storm Prediction Center (SPC), the total number of tornadoes during 2012 was just 936. This is the first time since 2002 that fewer than 1000 tornadoes have been recorded. The jet stream was positioned unusually far north in Canada during much of 2012, which brought drought to much of Tornado Alley. It's tough to get tornadoes when you're experiencing near-record drought conditions and very few thunderstorms. Saskatchewan, Canada saw as many tornadoes in July 2012 as all of the U.S., thanks to the more northward position of the jet stream.
Figure 4. June 24, 2012: A tornado spawned by Tropical Storm Debbie crosses Lake Winterset in Winter Haven, Florida. Another tornado from Debbie on this day caused the last tornado death in the U.S., at Venus in Highlands County, Florida. Image credit: wunderphotographer whgator3.
Record moisture and rains
Today's severe weather outbreak was helped by record levels of January moisture, as a flow of unusually moist air rode northwards from the Gulf of Mexico, where water temperatures were about 0.5°F above average. Meteorologists use a term called "precipitable water" to discuss how much water vapor is in the atmosphere. Precipitable water is defined as how much rain would fall on the ground if one took a vertical slice of the atmosphere above a given location and condensed all the water vapor into rain. Precipitable water levels tend to be highest in the summer, since warm air holds more waver vapor, and can exceed two inches in the Midwest U.S. In winter, though, it is rare to see precipitable water values higher than one inch. However, precipitable water was well over an inch well into Canada, and three upper air stations--Detroit, MI, Lincoln IL, and Caribou, Maine--set all-time records for January moisture, and four other stations had their 2nd highest January moisture on record. From the 00Z January 30 to 00Z January 31 upper air balloon soundings taken at the 73 radiosonde stations in the contiguous U.S., we observed these record or near-record precipitable water values for January:
Detroit, MI: New Record: 1.21" Old record: 1.20" 1/11/75
Lincoln, IL: New record: 1.46" Old Record: 1.35" 1/12/60
Caribou, Maine: New Record: 1.21" (Ties old record of 1.21" 1/14/2005)
Alpena, MI: 2nd place, 0.99". First place: 1.01", 1/5/97
Buffalo, NY: 2nd place, 1.21". First place: 1.34", 1/15/95
Wilmington, OH: 2nd place, 1.44" First place: 1.51", 1/12/2005
Gray, ME: 2nd place, 1.36" First place: 1.38" 1/20/96
Green Bay (4th), Albany, NY (4th), Sterling, VA (4th), Shreveport (6th), Little Rock (3rd), Nashville, TN (10th), Chatham, MA (10th), and Maniwawi, Quebec (4th) all had top-ten January precipitable water values. Radiosonde data goes back to 1948.
The exceptional moisture led to record rains in many regions of the Midwest, with numerous locations setting daily precipitation records. Two airports recorded their wettest January day on record, including Madison, WI (1.84", previous record 1.80" on January 1, 1892) and Houghton Lake, MI (1.21", old record 1.08" on in 1938.) Top-five wettest January days in recorded history were also set at Muskegon, MI (2.48"), Marquette, MI (1.21"), and South Bend, IN (1.94".) Here where I live, in Southeast Michigan, being outside yesterday was like walking through a surreal white soup. Rains like nothing I've ever seen in January fitfully poured from the sky throughout the day, ponding up on the frozen ground. Eerie white fog swirled over the sodden snow drifts as thunder rumbled overhead in temperatures 25°F above average. What planet was this? The heavy rains of 1.60" that fell in 26 hours at the nearby Flint airport made this month our wettest January in recorded history, with 3.66" of precipitation.
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