Alert archive / Iowa / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 21, NWS Des Moines, IA

May 16, 1999Sac County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 16, 1999, 9:24 AM CDT for Sac County, Iowa. It was in force for 41 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
May 16, 1999, 9:24 AM CDT (14:24 UTC)
Expired
May 16, 1999, 10:05 AM CDT
In force
41 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Sac County, IA

The radar

The Des Moines radar (KDMX), 135 km from the middle of the area, began a volume at 14:25 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.

What was reported inside it

TimeReportWhereRemark
May 16, 9:50 AM CDTHail 1.75Lake View, 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

Minneapolis, MN (KMPX), launched 12:00Z, 2.4 hours before the alert went out and 300 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 1999-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 1999-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
597 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDSM 161424 RRA
SVRDSM
IAC161-161505-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
924 AM CDT SUN MAY 16 1999

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN AND CENTRAL SAC COUNTY IN WEST CENTRAL IOWA

* UNTIL 1005 AM CDT

* AT 923 AM CDT... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 45
  MILES SOUTH OF SPENCER OR 7 MILES WEST NORTHWEST OF EARLY...
  MOVING EAST NORTHEAST AT 40 MPH.

* THIS STORM CAN BE EXPECTED NEAR...
   EARLY              BY 931 AM CDT
   NEMAHA             BY 938 AM CDT

THIS STORM HAS A HISTORY OF LARGE HAIL. GO INSIDE A STURDY BUILDING
AND STAY AWAY FROM WINDOWS.

SMALL/SEARCY

The office that day

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

IssuedProductOfficeCountiesLasted
May 16, 3:52 AM CDTSevere Thunderstorm WarningDMXClarke33 min
May 16, 4:09 AM CDTSevere Thunderstorm WarningDMXWarren36 min
May 16, 8:47 AM CDTSevere Thunderstorm WarningDMXGreene33 min
May 16, 9:19 AM CDTSevere Thunderstorm WarningDMXBoone, Greene36 min
May 16, 10:12 AM CDTSevere Thunderstorm WarningDMXBoone, Story33 min
May 16, 10:28 AM CDTSevere Thunderstorm WarningDMXCalhoun, Webster32 min
May 16, 10:47 AM CDTSevere Thunderstorm WarningDMXHamilton, Hardin33 min
May 16, 10:58 AM CDTSevere Thunderstorm WarningDMXWebster32 min
May 16, 11:18 AM CDTSevere Thunderstorm WarningDMXHardin32 min
May 16, 11:23 AM CDTSevere Thunderstorm WarningDMXHamilton, Wright47 min
May 16, 12:00 PM CDTSevere Thunderstorm WarningDMXFranklin45 min
May 16, 12:27 PM CDTSevere Thunderstorm WarningDMXButler63 min
May 16, 12:40 PM CDTSevere Thunderstorm WarningDMXBremer65 min
May 16, 12:46 PM CDTSevere Thunderstorm WarningDMXFranklin34 min
May 16, 1:28 PM CDTSevere Thunderstorm WarningDMXButler32 min
May 16, 1:43 PM CDTSevere Thunderstorm WarningDMXBremer62 min
May 16, 2:18 PM CDTSevere Thunderstorm WarningDMXBlack Hawk47 min
May 16, 3:42 PM CDTTornado WarningDMXCrawford33 min
May 16, 4:13 PM CDTTornado WarningDMXCrawford17 min
May 16, 4:20 PM CDTTornado WarningDMXCrawford50 min
May 16, 4:33 PM CDTSevere Thunderstorm WarningDMXHardin32 min
May 16, 4:38 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Grundy32 min
May 16, 4:43 PM CDTTornado WarningDMXSac47 min
May 16, 5:55 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer35 min
May 16, 6:13 PM CDTSevere Thunderstorm WarningDMXCass32 min
May 16, 6:17 PM CDTFlash Flood WarningDMXHardin2 hr
May 16, 6:26 PM CDTSevere Thunderstorm WarningDMXButler34 min
May 16, 6:38 PM CDTTornado WarningDMXAudubon, Cass47 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1999Every 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; radar from the NEXRAD Level II archive.