Alert archive / Iowa / Severe Thunderstorm Warnings in 2010
Severe Thunderstorm Warning 324, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 20, 2010, 3:11 PM CDT for 4 counties in Iowa. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 20, 2010, 3:11 PM CDT (20:11 UTC)
- Expired
- Aug 20, 2010, 3:45 PM CDT
- In force
- 34 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Appanoose County, IA, Lucas County, IA, Monroe County, IA, Wayne County, IA
The radar
The Des Moines radar (KDMX), 108 km from the middle of the area, began a volume at 20:14 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 20, 1:58 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 8.2 hours before the alert went out and 232 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 2447 J/kg
- Mixed-layer CIN
- -119 J/kg
- Mixed-layer LCL
- 1071 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 55 m²/s²
- 0-3 km storm-relative helicity
- 73 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 4.4
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 3:00 PM CDT, 11 minutes earlier.
Area forecast discussion, Aug 20, 3:00 PM CDT, 11 minutes before
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 300 PM CDT FRI AUG 20 2010 ...UPDATED 18Z AVIATION DISCUSSION... .SHORT TERM.../TONIGHT/ THUNDERSTORMS SHOULD DEVELOP OR CONTINUE NEAR OUTFLOW BOUNDARY OVER SOUTH CENTRAL IOWA EARLY THIS EVENING. DEVELOPMENT WAS BEING ADDED CONSIDERABLY BY A NICE LOOKING SHORTWAVE TROUGH APPROACHING FROM THE CENTRAL PLAINS. AIRMASS HAD DESTABILIZED OVER SOUTHEAST FA WHICH SHOULD FUEL STORMS LATE THIS AFTERNOON AND EVENING. DON/T THINK THE 12Z NAM/GFS HANDLE QPF THIS EVENING VERY WELL. 12Z RUN OF SPC 4KM WRF SEEM TO HAVE THE BEST HANDLE ON TSTMS OVER MO ATTM. IT TOOK THE BRUNT OF THIS ACTIVITY ESE AND NOT INTO IA. SMALL TSTM CLUSTER OVER SC IA ATTM SHOULD MOVE INTO INSTABILITY AND THEN OUT OF CWA EARLY THIS EVENING. WILL KEEP LINGERING POPS IN AFTER THIS UPSTREAM OF THE MID LEVEL SHORTWAVE TROUGH. ALTHOUGH LOCALLY HEAVY RAIN IS EXPECTED...EXPECT CONVECTION TO BE PROGRESSIVE ENOUGH TO NOT REQUIRE A FLASH FLOOD WATCH. MAY SEE SOME LATE NIGHT FOG AND ST ESPECIALLY EAST AND SOUTHEAST LATE TONIGHT. .LONG TERM.../SATURDAY THROUGH FRIDAY/ FOR THE PERIOD SATURDAY THROUGH MONDAY...MODELS ARE IN GOOD AGREEMENT WITH MASS FIELDS BUILDING AN UPPER LEVEL RIDGE OVER THE UPPER MIDWEST. HIGH PRESSURE AT THE SURFACE AND ALOFT SHOULD RESULT IN DRY WEATHER. AIRMASS NOT NEAR AS HOT EARLIER IN THE MONTH WITH 850 MB TEMPS STAYING AROUND 20C FOR THE MOST PART. TEMPERATURE PROFILE SUPPORTS HIGH TEMPS IN THE 80S SATURDAY THROUGH MONDAY. FOR THE PERIOD TUESDAY THROUGH FRIDAY...NEXT MAJOR SYSTEM DURING THE 7-DAY FORECAST PERIOD IS EXPECTED TO SLIDE THROUGH OUR REGION EARLY IN THE LONG TERM PD. PROGRESSIVE UPPER LEVEL TROF SLIDES ACROSS THE NORTHERN U.S. WITH AN ATTENDANT SURFACE COLD FRONT. SHRA/TSRA EXPECTED WITH THE COLD FROPA. ALTHOUGH THE BEST DYNAMICS ARE EXPECTED TO REMAIN NORTH OF OUR CWA... INSTABILITY WILL BE SUFFICIENT TO POSE A RISK OF SVR WX. THIS WX SYSTEM WILL HAVE A GOOD PUSH OF SEASONABLY COOL CANADIAN AIR BEHIND IT. THAT COOL AIR WILL ARRIVE IN OUR CWA BY TUESDAY NIGHT ONWARD...BRINGING US THE COOLEST TEMPERATURES THUS FAR THIS SEASON. AM CONCERNED THAT THE GOING TEMPS MAY NOT BE COOL ENOUGH...AS THIS AIR MASS WILL BE MORE FALL-LIKE THAN SUMMER-LIKE. THE REMAINDER OF THE LONG TERM PD IS EXPECTED TO REMAIN DRY. && .AVIATION... 20/18Z...SCATTERED SHOWERS AND THUNDERSTORMS ALONG A LINE ORIENTED FROM NE TO SW IOWA WILL SLOWLY MOVE EAST THIS AFTERNOON AND AFFECT ALO...DSM...AND OTM. CLEARING SKIES WILL THEN MOVE IN ACROSS THE STATE LATER TONIGHT SETTING THE STAGE FOR FOG DEVELOPMENT LATE TONIGHT/EARLY TOMORROW MORNING. MODELS INDICATE LVFR CONDITIONS...BUT LIGHT NORTHWESTERLY WINDS SHOULD MITIGATE DENSE FOG DEVELOPMENT...SO KEPT CONDITIONS TO WIDESPREAD MVFR...WITH SMALL WINDOW OF IFR CONDITIONS CENTERED AROUND 10Z. HAVE SIGNIFICANT IMPROVEMENT AFTER 12Z WITH VFR CONDITIONS THROUGH END OF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...JOHNSON AVIATION...BEITLICH LONG TERM...ZOGG
Hazardous weather outlook, Aug 20, 3:10 PM CDT, 1 minute before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 310 PM CDT FRI AUG 20 2010 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>072-081-082- 092-093-212015- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE- BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER- POWESHIEK-CASS-ADAIR-MADISON-ADAMS-UNION-TAYLOR-RINGGOLD- 310 PM CDT FRI AUG 20 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS EVENING. AN ISOLATED SEVERE STORM IS POSSIBLE...MAINLY SOUTHEAST OF A WATERLOO...DES MOINES TO ATLANTIC LINE. LOCALLY HEAVY RAIN IS ALSO POSSIBLE. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORM CHANCES RETURN TO THE FORECAST MONDAY NIGHT INTO TUESDAY. AT THIS TIME IT IS TOO EARLY TO DETERMINE THE THREAT OF SEVERE WEATHER. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS UNLIKELY. IAZ073>075-083>086-094>097-212015- WARREN-MARION-MAHASKA-CLARKE-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE- APPANOOSE-DAVIS- 310 PM CDT FRI AUG 20 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS ARE EXPECTED THIS EVENING. THERE IS A SLIGHT RISK OF SEVERE WEATHER...WITH DAMAGING WINDS AND LARGE HAIL THE MAIN SEVERE WEATHER THREATS. LOCALLY HEAVY RAIN IS POSSIBLE. RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR LOWER DES MOINES AND SKUNK RIVER BASINS. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORM CHANCES RETURN TO THE FORECAST MONDAY NIGHT INTO TUESDAY. AT THIS TIME IT IS TOO EARLY TO DETERMINE THE THREAT OF SEVERE WEATHER. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING.
In the hours before
Special weather statement, Aug 20, 12:53 PM CDT, 2 hours 18 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1253 PM CDT FRI AUG 20 2010 IAZ028-038-039-049-050-060-061-071>074-082>084-202000- BREMER-GRUNDY-BLACK HAWK-MARSHALL-TAMA-POLK-JASPER-ADAIR-MADISON- WARREN-MARION-UNION-CLARKE-LUCAS- INCLUDING THE CITIES OF...WAVERLY...GRUNDY CENTER...WATERLOO... MARSHALLTOWN...TOLEDO...DES MOINES...NEWTON...GREENFIELD... WINTERSET...INDIANOLA...KNOXVILLE...CRESTON...OSCEOLA...CHARITON 1253 PM CDT FRI AUG 20 2010 ...LOCALLY HEAVY RAIN POSSIBLE THROUGH THE AFTERNOON... A BROKEN LINE OF THUNDERSTORMS EXTENDING FROM NEAR CRESTON NORTHEAST THROUGH THE DES MOINES METRO AREA...BAXTER...MARSHALLTOWN...TRAER...AND INTO THE WATERLOO AND CEDAR FALLS AREA. LOCALLY BRIEF HEAVY RAIN AND OCCASIONAL CLOUD TO GROUND LIGHTNING WILL BE POSSIBLE WITH THIS BAND OF STORMS THROUGH 3 PM CDT. KLP
Special weather statement, Aug 20, 1:49 PM CDT, 1 hour 22 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 149 PM CDT FRI AUG 20 2010 IAZ072>074-083-201945- CLARKE-MADISON-MARION-WARREN- 149 PM CDT FRI AUG 20 2010 ...SMALL HAIL AND HEAVY DOWNPOURS POSSIBLE... AT 147 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER SOUTHEASTERN MADISON COUNTY...MOVING EAST AT 30 MPH. ONE HALF INCH DIAMETER HAIL...WINDS GREATER THAN 40 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... TRURO AND 9 MILES SOUTH OF PATTERSON BY 155 PM CDT... ST. CHARLES BY 200 PM CDT... NEW VIRGINIA AND 9 MILES SOUTH OF BEVINGTON BY 205 PM CDT... ST. MARYS AND 9 MILES SOUTH OF MARTENSDALE BY 210 PM CDT... INDIANOLA BY 225 PM CDT... MILO AND ACKWORTH BY 235 PM CDT... 9 MILES NORTH OF LACONA BY 240 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. PODRAZIK
Local storm report, Aug 20, 2:00 PM CDT, 1 hour 11 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
200 PM CDT FRI AUG 20 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0155 PM HEAVY RAIN 5 NE WINTERSET 41.40N 93.96W
08/20/2010 M1.80 INCH MADISON IA TRAINED SPOTTER
1.8 INCHES MEASURED SINCE 1130AM
&&
JBSpecial weather statement, Aug 20, 2:20 PM CDT, 51 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 220 PM CDT FRI AUG 20 2010 IAZ073-074-083>085-202015- CLARKE-LUCAS-MARION-MONROE-WARREN- 220 PM CDT FRI AUG 20 2010 ...THUNDERSTORM PRODUCING HAIL AND STRONG WINDS... AT 215 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER CENTRAL CLARKE COUNTY...MOVING EAST AT 35 MPH. PENNY SIZE HAIL...WINDS GREATER THAN 40 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...AND BRIEF HEAVY DOWNPOURS ARE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... WOODBURN BY 230 PM CDT... 9 MILES NORTH OF DERBY BY 240 PM CDT... LUCAS BY 245 PM CDT... CHARITON AIRPORT AND CHARITON BY 255 PM CDT... WILLIAMSON AND 8 MILES NORTH OF RUSSELL BY 305 PM CDT... 9 MILES SOUTH OF MELCHER-DALLAS BY 310 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. PODRAZIK
Special weather statement, Aug 20, 3:06 PM CDT, 5 minutes before
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</html>The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 2:24 PM CDT | Severe Thunderstorm Warning | DMX | Clarke, Lucas, Warren | 36 min |
| Aug 20, 3:25 PM CDT | Areal Flood Advisory | DMX | Wapello | 3 hr |
| Aug 20, 3:50 PM CDT | Flash Flood Warning | DMX | Wapello | 6 hr |
Nearby
Severe Thunderstorm Warnings in Iowa, 2010Every severe thunderstorm warning in 2010
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.