An upper-level disturbance triggered a cluster of strong to severe thunderstorms across Iowa and far northern Missouri during the pre-dawn hours of August 23rd. These storms tracked eastward into north-central Illinois by mid to late morning, producing gusty winds and heavy rainfall.
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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 ILX wrote it up.
An upper-level disturbance triggered a cluster of strong to severe thunderstorms across Iowa and far northern Missouri during the pre-dawn hours of August 23rd. These storms tracked eastward into north-central Illinois by mid to late morning, producing gusty winds and heavy rainfall. Some minor wind damage was reported in Peoria and Tazewell counties.
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 Lincoln, IL wrote its last area forecast discussion before the first event at Aug 23, 9:22 AM CST, 0 minutes earlier.
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1022 AM CDT Sat Aug 23 2014 .UPDATE... ISSUED AT 1022 AM CDT SAT AUG 23 2014 15z/10am radar mosaic shows large cluster of thunderstorms tracking E/NE across eastern Iowa into northwest Illinois. The storms extend as far south as Knox and northern Peoria counties, where frequent lightning and torrential rainfall is currently occurring. These particular cells will continue to push eastward across the far northern KILX CWA over the next 2-3 hours, primarily staying north of an Elmwood to Minonk line. Meanwhile, isolated storms have developed along an outflow boundary from this complex southward along a Canton to Springfield line. These cells will also track eastward and may become more numerous across east-central Illinois this afternoon. Have made some adjustments to PoPs today, mainly to go categorical across the far north this morning. Aside from the widely scattered convection, the main weather story today will be the hot and humid conditions. Afternoon highs are still on track to reach the upper 80s and lower 90s, with heat index readings exceeding 100 degrees. && .SHORT TERM...(Today and tonight) ISSUED AT 321 AM CDT SAT AUG 23 2014 Short-term concerns focus on convective development and heat today. Differing solutions among the high-res models give lower confidence on timing an coverage of storms today. Outflow boundaries lingering from yesterday's storms will likely play a role in today's development. The most noticeable boundary extending from SW to NE across our counties. One storm complex has remained active just to the SE of LWV, but is drifting SE. A couple of localized storm complexes to our west may evolve eastward this morning, as low level jet dynamics expand toward Illinois. That could help those storms affect areas NW of the IL river this morning. Current thinking is that expansion of the storm development along the outflow boundary generally keep storms NE of a line from Rushville to Effingham. Coverage may not be as extensive as the GFS and ECMWF are indicating, so we will continue to Chance PoPs mainly NE of a line from Peoria to Lawrenceville, with slight chances back west to Rushville to Effingham. By this evening, storms are expected to be mainly confined to areas east of I-57, then ending by midnight. The very moist air mass will remain in place today, with precipitable water values of over 2 inches. Therefore, locally heavy rainfall will be possible again today from any storms. Rainfall rates could reach as high as 2 to 3 inches per hour. Depending on the timing of convection and amount of sunshine during the afternoon, high temperatures today should reach the upper 80s and lower 90s. These readings, combined with dew points in the middle 70s, will produce heat index values of 100 to 105. Have continued the current Heat Advisory with no changes in coverage. Lows tonight will be held in the low to middle 70s due to very moist dew points. Patchy fog will likely develop under light winds and clearing skies. && .LONG TERM...(Sunday through Friday) ISSUED AT 321 AM CDT SAT AUG 23 2014 Expansive upper ridge remains in place through Tuesday. Main frontal boundary will be well to our north during this time, allowing for the tropical conditions to continue. Will need to watch for potential need to expand the heat advisory northward toward at least the I-74 corridor, as heat index values there should be approaching 105F from Sunday through Tuesday. However, heat index values today will be low enough that the 4-day criteria of 100-105F will probably not be met. With main frontal boundary to our northwest through Tuesday, any convection further south within the ridge will be more isolated and will struggle to break through the cap. Will have some 30-40% PoP's across the northeast half of the forecast area Tuesday afternoon along the fringes of a potential MCS. Will concentrate PoP's Tuesday night northwest of I-55, but main focus will likely be more northwest of the Illinois River. Ridge starts to break down on Wednesday as a broad trough heads eastward into the Plains. The GFS is more progressive with a broad wave reaching the Midwest on Thursday and ridging building across the Rockies, while the ECMWF cuts off a piece of energy from the main jet and drifts it eastward the remainder of the week. The former solution focuses the rain on the Wednesday/Thursday time frame, while the latter would linger the rain all the way into the weekend. A bit of a wild card will be the track of the tropical system lifting north from the Bahamas toward midweek, and how fast it ejects northeast (i.e. slowing down systems moving through the CONUS). The GFS ensemble spread is fairly wide by Thursday afternoon, indicating a lower confidence. The forecast right now will lean a bit more toward the progressive GFS, but will not clear it out as sharply or quickly behind the main front, with slight chances continuing Thursday night into Friday in many areas. Unfortunately, the varying solutions result in a wide temperature range toward the end of the week. The GFS would suggest highs only in the lower 70s by Friday, while the ECMWF keeps the very warm and humid conditions ongoing. Will favor the MEX MOS guidance for now with temperatures a couple degrees either side of 80. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 648 AM CDT SAT AUG 23 2014 Locally dense fog will keep CMI and BMI at VLIFR through 13z, with improvement to IFR by 14z, then VFR by 16z. IFR fog at SPI and DEC should improve to VFR by 15z. Light east winds at the surface will oscillate 20 degrees either side of 090 degrees through tonight. Wind speeds today should remain below 10kt under a weak pressure gradient. A few storms are expected to develop later this morning, primarily in the vicinity of a NW to SE oriented outflow boundary. Weak steering flow aloft will cause any storms to move very slowly, allowing them to drop heavy rain. Localized flooding will remain a concern for low lying areas. The high moisture content in the boundary layer will keep the chance for fog through tonight. For now we trended down to MVFR vis after 09z at all sites. && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056- 061>063-066>068-071>073. && UPDATE...BARNES SHORT TERM...SHIMON LONG TERM...GEELHART AVIATION...SHIMON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 554 AM CDT SAT AUG 23 2014 ILZ027>031-036>038-040-041-043>046-055-057-241100- CHAMPAIGN-DE WITT-DOUGLAS-EDGAR-FULTON-KNOX-MARSHALL-MASON-MCLEAN- PEORIA-PIATT-SCHUYLER-STARK-TAZEWELL-VERMILION-WOODFORD- 554 AM CDT SAT AUG 23 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND EAST CENTRAL ILLINOIS. .DAY ONE...TODAY AND TONIGHT LOCALLY DENSE EARLY MORNING FOG WILL LIFT SHORTLY AFTER SUNRISE. OTHERWISE, SCATTERED THUNDERSTORMS ARE EXPECTED TODAY. FREQUENT LIGHTNING AND LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. NONE OF THE STORMS SHOULD PRODUCE SEVERE WIND OR DAMAGING HAIL. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY HOT AND HUMID CONDITIONS WILL PREVAIL INTO EARLY NEXT WEEK. HIGH TEMPERATURES WILL CLIMB INTO THE LOWER 90S AND PEAK HEAT INDEX VALUES WILL RISE ABOVE THE 100 DEGREE MARK SATURDAY THROUGH MONDAY. THUNDERSTORM CHANCES RETURN TUESDAY THROUGH THURSDAY...AS THE HEAT DIMINISHES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. ILZ042-047>054-056-061>063-066>068-071>073-241100- CASS-CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-EFFINGHAM- JASPER-LAWRENCE-LOGAN-MACON-MENARD-MORGAN-MOULTRIE-RICHLAND- SANGAMON-SCOTT-SHELBY- 554 AM CDT SAT AUG 23 2014 ...HEAT ADVISORY IN EFFECT UNTIL 7 PM CDT MONDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS...EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...TODAY AND TONIGHT LOCALLY DENSE EARLY MORNING FOG WILL LIFT SHORTLY AFTER SUNRISE. THEN HEAT WILL INCREASE, WITH PEAK AFTERNOON HEAT INDEX READINGS BETWEEN 100 AND 105. A FEW THUNDERSTORMS MAY DEVELOP TODAY. FREQUENT LIGHTNING AND LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. NONE OF THE STORMS SHOULD PRODUCE SEVERE WIND OR DAMAGING HAIL. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH EARLY NEXT WEEK. HIGH TEMPERATURES WILL CLIMB INTO THE LOWER TO MIDDLE 90S WITH PEAK HEAT INDEX VALUES AROUND 105 DEGREES FROM SUNDAY THROUGH MONDAY. THUNDERSTORM CHANCES RETURN WEDNESDAY THROUGH THURSDAY NIGHT...AS THE HEAT DIMINISHES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. SHIMON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LINCOLN IL 931 AM CDT SAT AUG 23 2014 ILZ027-231600- KNOX- INCLUDING THE CITY OF...GALESBURG 931 AM CDT SAT AUG 23 2014 ...THUNDERSTORMS WITH VERY HEAVY RAINFALL MOVING INTO THE AREA... AT 925 AM CDT A LINE OF THUNDERSTORMS EXTENDING FROM ALEDO TO MONMOUTH WAS MOVING NORTHEASTWARD AT AROUND 20 MPH. THESE STORMS ARE PRODUCING FREQUENT LIGHTNING AND TORRENTIAL RAINFALL RATES OF 1.5 TO 2 INCHES PER HOUR. THE STORMS WILL MOVE INTO KNOX COUNTY BETWEEN 930 AND 1000 AM CDT...PRIMARILY IMPACTING LOCATIONS ALONG AND NORTHWEST OF A GALESBURG TO ALTONA LINE. MOTORISTS ARE URGED TO EXERCISE CAUTION AND BE PREPARED FOR POOR VISIBILITIES AND PONDING OF WATER ON ROADWAYS. IN ADDITION...MINOR FLOODING OF LOW-LYING AND POOR DRAINAGE AREAS IS POSSIBLE. THE STORMS WILL EXIT KNOX COUNTY BY 1100 AM CDT. BARNES
The Lincoln radar (KILX), 86 km away, was scanning. The volume nearest the first event began at 15:19 UTC.
2 thunderstorm wind. Local standard time, as filed.
A 6 to 7-inch diameter branch was broken off a cedar tree.
Several tree branches were blown down in Pekin.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2014Every state in 2014This day in weather historyWarnings in Illinois, August 2014
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: 540132, 540133.