Storms moved through the area, some produced severe weather.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LSX wrote it up.
Storms moved through the area, some produced severe weather.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS St. Louis, MO wrote its last area forecast discussion before the first event at Aug 18, 5:56 AM CST, 7 hours 39 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED AVIATION NATIONAL WEATHER SERVICE ST LOUIS MO 656 AM CDT TUE AUG 18 2015 .SHORT TERM: (THROUGH WEDNESDAY NIGHT) ISSUED AT 312 AM CDT TUE AUG 18 2015 ACTIVE WEATHER IS ANTICIPATED OVER THE NEXT FEW FORECAST PERIODS. AN UPPER LEVEL VORT MAX WILL SWING THROUGH NEB TODAY BEFORE IT LIFTS NORTHEASTWARD AND DEEPENS OVER IA/MN. A SECONDARY VORT MAX THEN MOVES THROUGH THE BASE OF THE TROUGH ON WED/WED NIGHT AND DRIVES A COLD FRONT THROUGH MO/IL. LARGE SCALE LIFT AHEAD OF THESE FEATURES WILL SUPPORT PERIODS OF SH/TS, ESPECIALLY TONIGHT AND TOMORROW. 0-6KM SHEAR WILL BE INCREASING THIS AFTN/EVE ACROSS THE NORTHWESTERN CWA. MOST MODELS AGREE ON ~30 KTS OF 0-6 KM SHEAR ACROSS THE NORTHWESTERN CWA BY 00Z, SUGGESTING THAT A FEW STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE. SHEAR VALUES THEN INCREASE MARKEDLY OVERNIGHT AND WED, BUT THE INSTABILITY IS MUCH LOWER UNTIL WED AFTN, AND EVEN THEN IT IS SPATIALLY LIMITED TO THE EXTREME SOUTHEASTERN CWA. DEPENDING ON THE SPEED OF THE COLD FRONT ON WED AND ON THE AMOUNT OF CLOUDINESS AHEAD OF THE FRONT, THERE MAY BE ENOUGH INSTABILITY ACROSS THE SOUTHEASTERN CWA TO TAP INTO 40-50 KTS OF 0-6KM SHEAR FOR A FEW STRONG TO SEVERE THUNDERSTORMS ON WED AFTN. PRECIPITATION GRADUALLY TAPERS OFF ON WED NIGHT WITH INCREASING SUBSIDENCE BEHIND THE FRONT. THE POST-FRONTAL AIR MASS LOOKS RATHER BRISK BY MID-AUGUST STANDARDS, AND UNSEASONABLY COOL TEMPERATURES (AROUND 5-10 DEG BELOW AVERAGE) ARE EXPECTED ON LATE WED NIGHT/EARLY THU MORNING. AIR TEMPERATURES IN THE 50S MIGHT BE A TO SURPRISE EARLY MORNING RISERS ON THURSDAY...A SURPRISE TO ANYONE WHO HASN'T SEEN THE WEATHER FORECAST. KANOFSKY .LONG TERM: (THURSDAY THROUGH MONDAY) ISSUED AT 312 AM CDT TUE AUG 18 2015 WEATHER SHOULD REMAIN MOSTLY DRY FOR THU-FRI UNTIL THE NEXT TROUGH SWINGS IN FROM THE PACIFIC NW INTO THE PLAINS ON SATURDAY. THIS SYSTEM MAY BRING SH/TS TO THE AREA FROM SATURDAY THROUGH SUNDAY. LOOK FOR RELATIVELY COOL TEMPERATURES TO PERSIST ON THU/FRI, A WARM-UP ON SAT/SUN WHEN WARM/MOIST AIR IS DRAWN NORTHWARD AHEAD OF THE NEXT LOW PRESSURE SYSTEM, AND ANOTHER COLD FRONT ON SUN/SUN NIGHT FOLLOWED BY COOLER TEMPERATURES AGAIN FOR SUN NIGHT INTO MON. KANOFSKY && .AVIATION: (FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 641 AM CDT TUE AUG 18 2015 RADIATIONAL FOG WILL REMAIN POSSIBLE AT KSUS AND KCPS THROUGH 14Z, OTHERWISE VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH MIDDAY. SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON WITH GOOD POTENTIAL FOR IMPACTS AT ALL OF THE TERMINALS. I HAVE CONSERVATIVELY INTRODUCED TEMPO GROUPS AT ALL OF THE TERMINALS FOR MVFR FLIGHT CONDITIONS, HOWEVER THE CONDITIONS COULD CERTAINLY DROP TO IFR WITH GUSTY WINDS. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO IMPACT THE TERMINALS THIS EVENING AS A COLD FRONT PUSHES INTO THE AREA. SPECIFICS FOR KSTL: VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH MIDDAY. SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON ACROSS EASTERN MO WITH GOOD POTENTIAL FOR IMPACTS AT KSTL. I HAVE CONSERVATIVELY INTRODUCED A TEMPO GROUP FOR MVFR FLIGHT CONDITIONS, HOWEVER THE CONDITIONS COULD CERTAINLY DROP TO IFR WITH GUSTY WINDS. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO IMPACT THE TERMINAL THIS EVENING AS A COLD FRONT PUSHES INTO THE AREA. GLASS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && WFO LSX
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 412 AM CDT TUE AUG 18 2015 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-190000- GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL- MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL- CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR IL-MONROE IL-KNOX MO- LEWIS MO-SHELBY MO-MARION MO-MONROE MO-RALLS MO-PIKE MO-BOONE MO- AUDRAIN MO-MONITEAU MO-COLE MO-OSAGE MO-CALLAWAY MO-MONTGOMERY MO- LINCOLN MO-GASCONADE MO-WARREN MO-ST. CHARLES MO-FRANKLIN MO- ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO- WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO- MADISON MO-REYNOLDS MO- 412 AM CDT TUE AUG 18 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS WILL SPREAD ACROSS THE AREA TODAY AND TONIGHT. SOME OF THE STORMS MAY BE STRONG TO SEVERE. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORMS WILL CONTINUE ON WEDNESDAY. SOME OF THE STORMS COULD BE STRONG TO SEVERE ACROSS PARTS OF SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS. THERE IS A CHANCE OF THUNDERSTORMS FROM FRIDAY NIGHT THROUGH SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE LATE THIS AFTERNOON AND TONIGHT ACROSS PARTS OF CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS. KANOFSKY
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
126 PM CDT TUE AUG 18 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0120 PM HAIL WRIGHT CITY 38.83N 91.02W
08/18/2015 E0.50 INCH WARREN MO TRAINED SPOTTER
HAIL RANGED FROM PEA TO MARBLE SIZE.
&&
DYEThe St Louis radar (KLSX), 44 km away, was scanning. The volume nearest the first event began at 19:37 UTC.
4 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds blew down a large tree limb onto a car 5 miles southeast of New Haven causing extensive damage. Numerous other limbs were blown down over far northern Franklin County.
Numerous large tree limbs were blown down near the intersection of Highways N and Z, south of Wentzville. Further southeast, a large tree was blown over in O'Fallon and a large section of a 30 foot tree was split off.
Thunderstorm winds blew down several power poles and power lines in the Layfayette Square area of St. Louis.
Thunderstorm winds blew down numerous tree limbs as well as several large trees and power lines. One house just east of New Bloomfield on County Road 436 had two windows broken from tree limbs. At least 20 trees were damaged on this property as well from the thunderstorm winds. One large tree was blown over and briefly blocked Highway UU east of Fulton.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2015Every state in 2015This day in weather historyWarnings in Missouri, August 2015
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 603956, 603961, 603963, 603967.