Alert archive / Iowa / Special Weather Statements in 2016

Special Weather Statement, NWS Des Moines, IA

August 11, 201610 counties in Iowa

NWS Des Moines, IA issued this special weather statement at Aug 11, 2016, 4:29 AM CDT for 10 counties in Iowa. It was in force for 61 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 11, 2016, 4:29 AM CDT (09:29 UTC)
Expired: Aug 11, 2016, 5:30 AM CDT
In force: 61 min
Issued by: NWS Des Moines, IA

Counties Calhoun County, IA, Cerro Gordo County, IA, Hancock County, IA, Humboldt County, IA, Kossuth County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Winnebago County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 136 km from the middle of the area, began a volume at 09:31 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 9.5 hours before the alert went out and 225 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 2446 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1020 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 191 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 9.6

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 11, 3:59 AM CDT, 30 minutes earlier.

Area forecast discussion, Aug 11, 3:59 AM CDT, 30 minutes before

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Hazardous weather outlook, Aug 10, 4:04 PM CDT, 12 hours 25 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
404 PM CDT WED AUG 10 2016

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-112115-
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-WARREN-MARION-MAHASKA-ADAMS-UNION-
CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-
APPANOOSE-DAVIS-
404 PM CDT WED AUG 10 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR INTO THIS EVENING.
LOCALIZED DAMAGING WIND GUSTS ARE POSSIBLE WITH THESE STORMS.
ADDITIONAL STORMS ARE EXPECTED TO ARRIVE AFTER MIDNIGHT TONIGHT
OVER PORTIONS OF CENTRAL AND NORTHERN IOWA. LOCALIZED HEAVY
RAINFALL AND DAMAGING WIND GUST WILL AGAIN BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

HEAT INDEX VALUES MAY REACH INTO THE 100 TO 105 DEGREE RANGE
THURSDAY AHEAD OF IMPENDING COLD FRONT.

WIDESPREAD THUNDERSTORMS WILL BE LIKELY ACROSS THE STATE BEGINNINGOVER
NORTHERN IOWA THURSDAY AND THE REMAINDER OF THE AREA THURSDAY
NIGHT AND FRIDAY. VERY HEAVY RAINFALL WITH LOCALIZED AMOUNTS IN
EXCESS OF 5 INCHES IS POSSIBLE. THIS MAY RESULT IN FLASH FLOODING
AND SIGNIFICANT RISES ON STREAMS. ISOLATED STRONG TO SEVERE
THUNDERSTORMS ARE ALSO POSSIBLE WITH DAMAGING WINDS THE PRIMARY
THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME HOWEVER
RAINFALL AND FLOODING REPORTS ARE ENCOURAGED AND HELPFUL.

In the hours before

Special weather statement, Aug 11, 4:29 AM CDT, 0 minutes before

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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 3:46 AM CDT	Flash Flood Watch	DMX	Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more	27 hr
Aug 11, 3:58 AM CDT	Heat Advisory	DMX	Adair, Adams, Appanoose, Audubon, Cass, Clarke and 14 more	16 hr
Aug 11, 5:35 AM CDT	Special Weather Statement	DMX	Cerro Gordo, Franklin, Hamilton, Webster, Worth, Wright	55 min
Aug 11, 6:43 PM CDT	Special Weather Statement	DMX	Boone	62 min
Aug 11, 6:52 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Crawford, Sac	53 min

Nearby

Special Weather Statements in Iowa, 2016 Every special weather statement in 2016

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.