A bow echo dropped southward out of Wisconsin across Stephenson County producing damaging winds.
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 bow echo dropped southward out of Wisconsin across Stephenson County producing damaging winds.
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 Aug 11, 1:45 PM CST, 11 hours 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 245 PM CDT SAT AUG 11 2007 .SYNOPSIS... SLOW MOVING COOL FRONT APPROACHING IOWA WITH SOUTH WINDS OF 10 TO 20 MPH AHEAD OF FRONT ALLOWING WAA TO PUSH AREA TEMPERATURES INTO UPPER 80S TO AROUND 90F AT 2 PM WITH HEAT INDICES OF 90 TO 100F. UPPER AIR ANALYSIS SHOWS WEAK UPPER WAVE AND UPPER DIFFLUENCE IN NORTHERN PLAINS TO SUPPORT EVENING AND OVERNIGHT CONVECTION ALONG FRONT AS IT ARRIVES IN NORTH 1/2 MAINLY AFTER MIDNIGHT. DEWPOINTS OF 68 TO 73F AND SOUTH WINDS TO RESULT IN ANOTHER MUGGY AND WARM NIGHT. && .SHORT TERM...TONIGHT AND TOMORROW... KEPT MIN TEMPS ON HIGH SIDE OF GUIDANCE AHEAD OF COOL FRONT. UPPED POPS INTO 30 PERCENT CHANCE ALONG HIGHWAY 20 AND SLIGHT CHANCE TO I- 80 AFTER MIDNIGHT AS PROPAGATION VECTORS SUGGEST SOME BACKBUILDING INTO AREA ALONG WITH DECENT UPPER LEVEL DIFFLUENCE. LOCAL TOOLS SUPPORT HIGH WBZ AND MODERATE INSTABILITY TO KEEP STRONGEST STORMS BELOW SEVERE LEVELS WITH ISOLATED GUSTY WINDS OF 30-45 MPH MID/LATE EVENING HOURS INTO EARLY OVERNIGHT. HIGH PWS OF 1.5+ INCHES MAY ALLOW FOR BRIEF HEAVY RAINFALL. SUNDAY...KEPT SLIGHT CHANCE SE 1/3 AS FRONT MOVES ACROSS BUT LIMITED MID/UPPER LEVEL FORCING SUGGEST COVERAGE TO BE REDUCED MORE THAN NORMAL WITH A BOUNDARY. BUT...IF MCS MORE VIGOROUS OVERNIGHT THAN COULD ENHANCE FORCING AND PASS FOR NEXT SHIFTS TO MONITOR THAT MAY RESULT IN HIGHER POPS. WITH COMPRESSIONAL HEATING IN SOUTH HALF MAX TEMPS TO REACH MID 90S WITH HEAT INDICES OF 100 TO 105F THAT MAY PUSH HEAT ADVISORY CRITERIA FOR SUBSEQUENT SHIFTS. ..NICHOLS.. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. THE COMING WEEK WILL BE VERY INTERESTING. NONLINEAR PROCESSES ARE THE PRIMARY FACTORS DRIVING THE SENSIBLE WX. MANY MCS EPISODES ARE EXPECTED AND THE PROBABILITY FOR ABOVE NORMAL RAINFALL IS HIGH WITH A STALLED EAST WEST BOUNDARY JUST SOUTH OF THE CWFA. TEMPERATURES ALSO EXPECTED TO BE QUITE VARIABLE WITH A SIGNIFICANT GRADIENT ACROSS THE CWFA. MODELS SHOW A RESPECTABLE DISTURBANCE TOPPING THE RIDGE SUNDAY WHICH WILL BE THE GENESIS FOR MCS (BRAVO) LATE SUNDAY NIGHT INTO MONDAY MORNING. AHEAD OF SAID SHORTWAVE...DAYTIME HEATING SHOULD RESULT IN SOME ISOLATED TSRA/SHRA ACROSS ABOUT THE SOUTHERN 2/3RDS OF THE CWFA DURING THE EVENING. STRONG SIGNALS REGARDING MOISTURE/SPEED CONVERGENCE POINT TO MCS (CHARLIE) DEVELOPING ALONG THE MISSOURI RIVER MONDAY EVENING. SAID MCS SHOULD MOVE GENERALLY EAST AND ARRIVE LATE MONDAY NIGHT/TUESDAY. BOUNDARIES LEFT OVER FROM THIS MCS SHOULD ALLOW DIURNAL CONVECTION TO FIRE TUESDAY AFTERNOON/EVENING ACROSS THE SOUTH THIRD OF THE CWFA AS THE WEAK FRONT MOVES THROUGH THE AREA. THINGS REALLY GET INTERESTING TUESDAY NIGHT/WEDNESDAY AS THE LLJ ADVECTS MOISTURE INTO THE REGION. MCS (DELTA) SHOULD DEVELOP IN NORTHWEST IOWA AND TRACK EAST SOUTHEAST ACROSS THE NORTHERN THIRD OR HALF OF THE CWFA. THIS MCS HAS THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL AND BOUNDARIES LEFT OVER SHOULD AID IN SCATTERED CONVECTION DEVELOPING ACROSS THE ENTIRE AREA WEDNESDAY. MCS (ECHO) TO DEVELOP IN ABOUT THE SAME AREA AS DELTA AND WILL AFFECT THE CWFA LATE WEDNESDAY NIGHT/THURSDAY. AGAIN...THIS MCS COULD PRODUCE LOCALLY HEAVY RAINFALL WITH THE NORTH HALF FAVORED ATTM. PER ECMWF...A RESPECTABLE CANADIAN HIGH SHOULD PUSH THE FRONT FAR ENOUGH SOUTH TO ALLOW A DRY FRIDAY/FRIDAY EVENING. HOWEVER... CONFIDENCE IN THIS IS NOT HIGH WITH THE 850 MB BAROCLINIC ZONE STILL OVER THE AREA. RETURN FLOW DEVELOPS RAPIDLY FRIDAY NIGHT AND MCS (FOXTROT) SHOULD FIRE SOMEWHERE IN NORTHERN IOWA/SOUTHERN MINNESOTA. THE MOVEMENT OF THIS MCS IS QUESTIONABLE DUE TO THE HIGHLY SMOOTHED MODEL SOLUTIONS REGARDING MOISTURE/SPEED CONVERGENCE AT 850MB. POTENTIAL THERE IT MAY AFFECT THE CWFA SO HAVE OPTED TO GO WITH SILENT 20 POPS FOR NEXT SATURDAY. ...08... && .AVIATION... VFR CONDITIONS WITH FAIR SKIES THOUGH PERIOD WITH SOME ISOLATED COVERAGE OF THUNDERSTORMS AFTER 02Z WITH LOCALIZED MVFR OF 1 TO 3 MILES IN RAIN WITH CEILINGS OF 2 TO 4,000 FT. SOME AREAS OF LIGHT RADIATIONAL FOG AROUND AND ESPECIALLY AFTER MIDNIGHT MAINLY IN THE 2 TO 6 MILE RANGE UNTIL 8 AM. ..NICHOLS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && NICHOLS/08
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 503 AM CDT SAT AUG 11 2007 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-121015- 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- 503 AM CDT SAT AUG 11 2007 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... TEMPERATURES IN THE LOW TO MID 90S AND INCREASING HUMIDITY TODAY WILL COMBINE TO PRODUCE HEAT INDICES OF AROUND 100 DEGREES IN PORTIONS OF SOUTHEAST IOWA...FAR WEST CENTRAL ILLINOIS AND NORTHEAST MISSOURI. A FRONTAL SYSTEM WILL DROP SOUTH TOWARD THE DUBUQUE...TO CEDAR RAPIDS AREA BY LATE TONIGHT. OUT AHEAD OF IT...THERE WILL BE A CHANCE FOR SOME THUNDERSTORMS THIS EVENING AND OVERNIGHT GENERALLY ALONG AND NORTH OF A LINE FROM WEST OF CEDAR RAPIDS... TO FREEPORT IN NORTHWEST ILLINOIS. IF STORMS DO MANAGE TO GET DOWN INTO THESE AREAS TONIGHT...THERE WILL BE A LOW CHANCE THAT A FEW STORMS WILL PRODUCE DAMAGING WINDS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY... SUNDAY THE COLD FRONT CONTINUES TO MOVE SOUTHEAST ACROSS THE OUTLOOK AREA IN THE MORNING. BY THIS TIME NO STORMS ARE EXPECTED IN THE FORECAST AREA...THOUGH ISOLATED CELLS ARE POSSIBLE CLOSE TO THE BOUNDARY. A SECOND FRONT IS EXPECTED TO MOVE THROUGH THE AREA ON TUESDAY WITH LOW CHANCES OF SHOWERS AND THUNDERSTORMS. LATER IN THE WEEK...SHOWERS AND THUNDERSTORMS ARE EXPECTED LATE TUESDAY NIGHT THROUGH WEDNESDAY AND WEDNESDAY NIGHT. IT IS TOO EARLY TO DETERMINE THE POTENTIAL FOR SEVERE WEATHER OR HEAVY RAINS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA IL 140 AM CDT SUN AUG 12 2007 ILZ001-002-120815- JO DAVIESS-STEPHENSON- INCLUDING THE CITIES OF...GALENA...FREEPORT 140 AM CDT SUN AUG 12 2007 ...A LINE OF STRONG THUNDERSTORMS PUSHING OUT OF SOUTHERN WISCONSIN AND INTO NORTHWEST ILLINOIS... A LINE OF STRONG THUNDERSTORMS WILL MOVE QUICKLY SOUTHEAST OUT OF SOUTHERN WISCONSIN AND REACH A STOCKTON...TO FREEPORT LINE BY 220 AM. THESE STORMS WILL BE CAPABLE OF PRODUCING WIND GUSTS UP TO 50 MPH...FREQUENT AND INTENSE CLOUD TO GROUND LIGHTNING...AND TORRENTIAL DOWNPOURS AT RATES OF OVER AN INCH AN HOUR. HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. IF YOU LIVE IN NORTHEAST PORTIONS OF JO DAVIESS AND NORTHERN STEPHENSON COUNTIES...MOVE INDOORS AS THESE STORMS APPROACH YOUR AREA. 12
The Milwaukee radar (KMKX), 97 km away, was scanning. The volume nearest the first event began at 06:55 UTC.
3 thunderstorm wind. Local standard time, as filed.
Winds estimated to be 65 mph blew down some tree limbs in Rock Grove, IL.
Winds estimated to be 65 mph blew down a large tree limb on the north side of Freeport, IL.
Winds estimated to be 65 mph blew down a dead tree onto Highway 73 north of Lena, IL.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2007Every state in 2007This day in weather historyWarnings in Illinois, August 2007
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: 56826, 56827, 56829.