Alert archive / Iowa / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 105, NWS Des Moines, IA

July 2, 1999Hamilton County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 2, 1999, 5:46 PM CDT for Hamilton County, Iowa. It was in force for 34 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Jul 2, 1999, 5:46 PM CDT (22:46 UTC)
Expired: Jul 2, 1999, 6:20 PM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Whole counties

County Hamilton County, IA

What was reported inside it

Time	Report	Where	Remark
Jul 2, 6:00 PM CDT	Hail 1.75	Stanhope, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.8 hours before the alert went out and 250 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: 217 J/kg
Mixed-layer CIN: -357 J/kg
Mixed-layer LCL: 1083 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 406 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Jul 2, 3:45 PM CDT, 2 hours 1 minute earlier.

Area forecast discussion, Jul 2, 3:45 PM CDT, 2 hours 1 minute before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
345 PM CDT FRI JUL 2 1999

THUNDERSTORM COMPLEX CURRENTLY WORKING ITS WAY ACROSS CENTRAL IOWA
WITH THE STRONGEST STORMS LOCATED IN SOUTHERN DALLAS AND WEBSTER
COUNTIES. THUNDERSTORM PROPAGATING TO THE SOUTHEAST INTO UNSTABLE
ATMOS. LOW LEVEL SHEAR WILL HELP KEEP SOME THUNDERSTORM SEVERE.
CAPPING OVER SOUTHEAST SECTION OF THE DES MOINES FORECAST AREA IS
RELATIVELY WEAK WITH CAPPING STRONGER OVER THE REMAINDER OF THE
FORECAST AREA. DALLAS COUNTY STORM IS MOVING ALONG OR JUST TO THE
NORTH OF THE WARM FRONTAL BOUNDARY. 850 MB WARM FRONT OVER CENTRAL
SECTION OF THE STATE. THINKING ACTIVITY NORTH OF THE WARM WILL
CONTINUE UNDER THE LOW LEVEL WARM ADVECTION AND LIFT OVER THE FRONT.
THIS IS THE REASON FOR THE HIGHER POPS IN NORTHERN SECTIONS OF THE
FORECAST AREA. WARM FRONT CONTINUES TO LIFT NORTH TONIGHT SHIFTING
THE THREAT NORTHWARD INTO SOUTHERN MINNESOTA.  WARM ADVECTION
CONTINUES SATURDAY...QUICKLY STRENGTHENING THE CAP BY MIDDAY SO THAT
ANY CHANCE OF CONVECTION WILL BE SUPPRESSED.

EXTENDED...
WILL BE HOT AND HUMID SUNDAY AND MONDAY. AS DAVENPORT NOTED A COLD
FRONT ON MONDAY INTO MONDAY NIGHT WILL HELP COOL THE ATMOSPHERE OFF
TUESDAY AND WEDNESDAY. AGREE AS WELL ENOUGH CAPPING AND STABILITY TO
KEEP ANY ACTIVITY SUPPRESSED.

.DSM...NONE

In the hours before

Local storm report, Jul 2, 5:31 PM CDT, 15 minutes before

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Local storm report, Jul 2, 5:31 PM CDT, 15 minutes before

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Local storm report, Jul 2, 5:34 PM CDT, 12 minutes before

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Local storm report, Jul 2, 5:34 PM CDT, 12 minutes before

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Local storm report, Jul 2, 5:35 PM CDT, 11 minutes before

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Local storm report, Jul 2, 5:35 PM CDT, 11 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
Jul 2, 10:47 AM CDT	Tornado Warning	DMX	Crawford	48 min
Jul 2, 11:29 AM CDT	Tornado Warning	DMX	Crawford	36 min
Jul 2, 12:01 PM CDT	Severe Thunderstorm Warning	DMX	Carroll	34 min
Jul 2, 12:22 PM CDT	Severe Thunderstorm Warning	DMX	Carroll	33 min
Jul 2, 12:37 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Guthrie	48 min
Jul 2, 12:45 PM CDT	Severe Thunderstorm Warning	DMX	Greene	50 min
Jul 2, 1:22 PM CDT	Severe Thunderstorm Warning	DMX	Dallas	48 min
Jul 2, 1:42 PM CDT	Severe Thunderstorm Warning	DMX	Audubon	48 min
Jul 2, 2:07 PM CDT	Tornado Warning	DMX	Audubon	33 min
Jul 2, 2:28 PM CDT	Severe Thunderstorm Warning	DMX	Guthrie	47 min
Jul 2, 3:00 PM CDT	Severe Thunderstorm Warning	DMX	Adair	65 min
Jul 2, 3:10 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun	35 min
Jul 2, 3:16 PM CDT	Severe Thunderstorm Warning	DMX	Guthrie	19 min
Jul 2, 3:23 PM CDT	Severe Thunderstorm Warning	DMX	Webster	47 min
Jul 2, 3:29 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Madison	36 min
Jul 2, 4:05 PM CDT	Severe Thunderstorm Warning	DMX	Madison	35 min
Jul 2, 4:43 PM CDT	Severe Thunderstorm Warning	DMX	Webster	32 min
Jul 2, 5:12 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton	33 min
Jul 2, 5:21 PM CDT	Severe Thunderstorm Warning	DMX	Boone	34 min
Jul 2, 5:24 PM CDT	Severe Thunderstorm Warning	DMX	Webster	31 min
Jul 2, 5:38 PM CDT	Severe Thunderstorm Warning	DMX	Boone	47 min
Jul 2, 5:57 PM CDT	Severe Thunderstorm Warning	DMX	Story	48 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1999 Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.