A upper disturbance interacted with a diffuse warm front to spawn two isolated, brief tornadoes in Illinois.
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 DVN wrote it up.
A upper disturbance interacted with a diffuse warm front to spawn two isolated, brief tornadoes in Illinois.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at May 26, 5:49 AM CST, 3 hours 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 649 AM CDT TUE MAY 26 2015 .SYNOPSIS... ISSUED AT 332 AM CDT TUE MAY 26 2015 SHOWERS ARE PERCULATING OVER NORTHEAST IA EARLY THIS AM IN WAKE OF PASSING OUTFLOW BOUNDARY. OVERALL... RAIN CHANCES WILL BE INCREASING TODAY AS A SHORTWAVE TROUGH OVER KS/OK LIFTS NORTHEAST INTO THE UPPER MIDWEST WHILE MERGING WITH REMNANT UPPER LEVEL LOW SHIFTING EAST FROM NE. ISENTROPIC ASCENT...VORTICITY ADVECTION... INCREASING LOW LEVEL CONVERGENCE WITH PASSING MESO-LOW ALONG WITH SURGE OF MOISTURE/THETA-E RIDGE WITH PW VALUES CLIMBING TO NEAR 1.5 INCHES WILL ALL RESULT IN FAIRLY GOOD COVERAGE OF SHOWERS AS DAY PROGRESSES WITH A FEW STORMS AS WELL. WEAK COOL FRONT/SURFACE TROUGH TO MOVE INTO THE AREA TONIGHT AND SHOULD RESULT IN TAPERING RAIN CHANCES. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CDT TUE MAY 26 2015 INCREASING COVERAGE OF SHOWERS AND A FEW STORMS EXPECTED THIS AM WITH FORCING AND MOISTURE ADVECTION AHEAD OF APPROACHING SHORTWAVE AND SURFACE MESO-LOW. LOCALLY HEAVY RAIN WILL BE THE MAIN CONCERN... WITH THE FOCUS FOR HIGHER RAIN AMOUNTS (POTENTIALLY POCKETS OF RAINFALL OF 1-2 INCHES) BEING OVER THE WESTERN CWA... ESPECIALLY NORTHWEST OF REMNANT OUTFLOW BOUNDARY FROM NEAR IOW- DBQ WHERE LIFT IS MAXIMIZED WITH INCREASING CONVERGENCE FROM APPROACHING MES0-LOW AND UPPER LEVEL DIFFLUENCE AHEAD OF SHORTWAVE. CANT RULE OUT SOME FLOODING ISSUES BEING POSSIBLE ESPECIALLY WITH ANY TRAINING AND PROLONGED BOUTS OF HIGHER RAINFALL RATES. THIS AFTERNOON IT WOULD APPEAR AS THOUGH GREATER COVERAGE OF PCPN WILL MIGRATE NORTH OF I-80 AS SYSTEM LIFTS THROUGH THE REGION AND MID LEVEL DRY INTRUSION ENVELOPS MUCH OF THE AREA. THIS MAY ALLOW FOR SOME PARTIAL SUNSHINE WHICH COULD ALLOW FOR SOME DESTABILIZATION AND DEVELOPMENT OF SCATTERED SHOWERS AND STORMS. SUFFICIENT SHEAR WITH 0-6KM BULK SHEAR 30-35 KTS FOR POTENTIAL OF A STRONGER STORM OR TWO SHOULD SUFFICIENT DESTABILIZATION OCCUR. AS FOR HIGHS TODAY... AS THE CLOUDS/PCPN GO... SO GO THE TEMPS AND THEREFORE A TRICKY TEMP FORECAST WITH BUST POTENTIAL. HAVE NUDGED DOWN HIGHS 1-2 DEGS NORTHWEST CWA WHERE LIKELIHOOD OF MORE RAIN AND LINGERING CLOUDS AND HAVE AROUND 70 OR LOWER 70S THERE WITH MID/UPPER 70S ELSEWHERE. TONIGHT... ANTICIPATE GRADUAL TAPERING OF RAIN CHANCES WITH FOCUS SHIFTING MORE TO THE SOUTH IN TIME AS WEAK COOL FRONT/TROUGH MOVES INTO THE REGION. LOWS COOLEST NORTHWEST (MID/UPPER 50S) TO WARMEST SOUTHEAST (LOWER 60S) UNDER PARTLY TO MOSTLY CLOUDY SKIES AND LIGHT SOUTHWESTERLY WINDS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 332 AM CDT TUE MAY 26 2015 MAIN FORECAST CONCERN FOR THE LONG TERM FORECAST ARE THE CHANCES FOR POPS AT THE BEGINNING OF THE PERIOD AND THEN THE CHANCE FOR POPS THIS WEEKEND. ACTIVE WEATHER PATTERN REMAINS IN PLACE ACROSS THE AREA THROUGH THE LONG TERM WITH CHCS OF POPS VIRTUALLY EVERY DAY WITH THE EXCEPTION OF A SHORT PERIOD WEDNESDAY INTO THURSDAY. WEDNESDAY...THE CURRENT TROF THAT HAS PLAGUED THE CENTRAL UNITED STATES FOR THE PAST WEEK OR SO FINALLY EJECTS OUT OF THE PLAINS. THIS OCCURS BECAUSE ANOTHER TROF IS BUILDING IN FROM THE NW. THIS GIVES US ONLY ABOUT 24 HOURS OF H5 RIDGING UNTIL THE NEXT TROF TURNS THE FLOW TO THE SW ON THURSDAY. WEDNESDAY AFTERNOON INTO THURSDAY LATE AFTERNOON SHOULD BE QUIET AND PLEASANT. THURSDAY THE FLOW TURNS SSW ACROSS THE AREA. THIS SHOULD USHER MOISTURE AND SHRTWVS INTO THE AREA AGAIN FOR THURSDAY NIGHT INTO THE WEEKEND. THE MODELS...ESPECIALLY THE SPECTRAL MODELS WITH LARGER GRID SPACING SEEM TO BE OVERDOING IT WITH COVERAGE OF THE POPS. THEY HAVE DONE IT WITH THE CURRENT SYSTEM. THIS COULD BE DUE TO THE CONVECTION DOWNSTREAM SOUTH OF HERE OR ISSUES WITH PARAMETRIZATION SCHEMES. REGARDLESS...THEY DEPICT DIURNAL CONVECTION. THE NAM SEEMS TO BE THE BEST AS FAR AS COVERAGE OF POPS. THIS SUGGESTS THAT THURSDAY MOST OF THE SHOWERS AND STORMS WILL BE WEST OF THE AREA UNTIL NEAR 00Z. AFTER 00Z FRIDAY SHOWERS AND STORMS WILL ADVECT INTO THE AREA AND LIKELY AFFECT NW ZONES THE MOST FRIDAY NIGHT. OVERALL TIMING AND STRUCTURE OF THE FORCING APPEARS TO BE CONSISTENT THROUGH 12Z SATURDAY. THERE ARE SMALL DIFFERENCES BUT NOTHING THAT WOULD AFFECT A FORECAST THIS FAR OUT. THOSE DIFFERENCES WOULD LIKELY AFFECT MESOSCALE FEATURES THAT ARE INHERENTLY DIFFICULT TO FORECAST THIS FAR OUT. THE OVERALL TROF IS SLOW TO LEAVE THE AREA. COOLER AIR WILL BE PULLED INTO THE AREA SUNDAY...LEADING SUNDAY AND SUNDAY NIGHT BEING CHILLY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 638 AM CDT TUE MAY 26 2015 SHOWERS AND A FEW STORMS WILL BE FOUND THIS AM WITH MVFR TO LOCAL IFR CONDITIONS. THE RAIN WILL TAPER OFF FROM SOUTH TO NORTH MID MORNING THROUGH EARLY AFTERNOON. WILL HAVE A CHANCE AT SCATTERED SHOWERS AND A FEW STORMS THIS AFTERNOON AND EVENING AHEAD OF A WEAK SURFACE TROUGH... BUT LOW CONFIDENCE ON OCCURRENCE AT TERMINALS THUS HAVE LEFT OUT ANY MENTION OF THIS CHANCE FOR NOW. CONDITIONS EXPECTED TO IMPROVE TO VFR THIS AFTERNOON AND REMAIN GENERALLY VFR THROUGH TONIGHT...WITH MVFR CONDITIONS IN ANY SCATTERED SHOWER OR STORM ACTIVITY. SOUTH TO SOUTHEAST WINDS AROUND 10 KTS AND GUSTY AT TIMES WILL VEER TO SOUTHWEST 10-20 KTS THIS AFTERNOON THEN DIMINISH BLO 10 KTS TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...05 SHORT TERM...05 LONG TERM...GIBBS AVIATION...05
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 405 AM CDT TUE MAY 26 2015 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-270915- BUCHANAN-DELAWARE-DUBUQUE-BENTON-LINN-JONES-JACKSON-IOWA-JOHNSON- CEDAR-CLINTON-MUSCATINE-SCOTT-KEOKUK-WASHINGTON-LOUISA-JEFFERSON- HENRY IA-DES MOINES-VAN BUREN-LEE-JO DAVIESS-STEPHENSON-CARROLL- WHITESIDE-ROCK ISLAND-HENRY IL-BUREAU-PUTNAM-MERCER-HENDERSON- WARREN-HANCOCK-MCDONOUGH-SCOTLAND-CLARK- 405 AM CDT TUE MAY 26 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL ILLINOIS...NORTHWEST ILLINOIS...WEST CENTRAL ILLINOIS...EAST CENTRAL IOWA...NORTHEAST IOWA...SOUTHEAST IOWA AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT A FEW THUNDERSTORMS CAN BE EXPECTED OVER THE OUTLOOK AREA THROUGH THIS EVENING. THE RISK OF SEVERE WEATHER APPEARS LOW AT THIS TIME HOWEVER... ISOLATED STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE POSSIBLE MAINLY THIS AFTERNOON AND EVENING. HEAVY RAINFALL WILL ALSO BE FOUND WITH ANY STORMS... WITH LOCALIZED FLASH FLOODING POSSIBLE IN ANY AREAS THAT SEE REPEATED STORM ACTIVITY OR SEE A PROLONGED PERIOD OF HIGHER RAINFALL RATES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORMS RETURN TO THE AREA THURSDAY EVENING THROUGH THE WEEKEND. AT THIS TIME THE SEVERE WEATHER THREAT APPEARS LOW...BUT CANNOT BE RULED OUT....ESPECIALLY FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
The Quad Cities radar (KDVN), 55 km away, was scanning. The volume nearest the first event began at 14:59 UTC.
2 tornado, 1 thunderstorm wind. Local standard time, as filed.
An EF1 tornado with winds of 100 mph tracked from 6.75 miles south-southwest of Atkinson to 3 miles south of Atkinson. Tornado began at 959 am and ended at 1004 am CDT, causing damage mainly to trees and farm outbuildings.
A survey completed with assistance from Bureau County Emergency Management showed a short tornado damage path with damage mainly to trees and a machine shed. Tornado winds were estimated at 90 mph.
A strong downburst damaged a barn, some trees, and the porch of a house.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2015Every state in 2015This day in weather historyThe tornado archive for Illinois, 2015Warnings in Illinois, May 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: 582903, 582904, 583292.