Alert archive / Iowa / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 29, NWS Des Moines, IA

May 18, 2000Poweshiek County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 18, 2000, 12:48 PM CDT for Poweshiek County, Iowa. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: May 18, 2000, 12:48 PM CDT (17:48 UTC)
Expired: May 18, 2000, 1:20 PM CDT
In force: 32 min
Issued by: NWS Des Moines, IA
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 95 km from the middle of the area, began a volume at 17:50 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
May 18, 11:30 AM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 5.8 hours before the alert went out and 173 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: 1779 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 796 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 178 m²/s²
0-3 km storm-relative helicity: 310 m²/s²
Significant tornado parameter: 2.4
Supercell composite: 10.8

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KDMX 181749
SVRDSM
IAC157-181815-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1248 PM CDT THU MAY 18 2000

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  POWESHIEK COUNTY IN CENTRAL IOWA

* UNTIL 120 PM CDT

* AT 1248 PM CDT DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM WITH
  LARGE HAIL 4 MILES SOUTH OF BROOKLYN...OR ABOUT 45 MILES NORTH OF
  OTTUMWA...MOVING NORTHWEST AT 30 MPH.

* SOME LOCATIONS THREATENED THROUGH 120 PM CDT...
  BROOKLYN
  GRINNELL

OTHER SEVERE STORMS OVER EASTERN JASPER COUNTY WILL BE MOVING 
NORTHEAST AROUND 20 MPH...REACHING SEARSBORO TO GRINNELL BY 110 PM.  

DAMAGING HAIL UP TO TWO INCHES IN DIAMETER IS LIKELY IN ALL OF 
POWESHIEK COUNTY.

A TORNADO WATCH IS ALSO IN EFFECT FOR THE WARNED AREA. REMEMBER...
SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING.

LAT...LON 4152 9275 4158 9232 4186 9231 4186 9277

SEARCY
NNNN

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 May 18, 8:50 AM CDT, 3 hours 58 minutes earlier.

Area forecast discussion, May 18, 8:50 AM CDT, 3 hours 58 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
850 AM CDT THU MAY 18 2000

WILL BE MAKING A QUICK UPDATE TO DIMINISH PRECIP IN THE NORTH AND
CUT BACK ON MORNING PRECUIP WORDING SOUTH.  BEST SEVERE POTENTIAL NOW
LOOKS TO BE SOUTH OF I-80...MAYBE A LITTLE FARTHER SOUTH...AND EAST
OF I-35.  GOOD MINI SUPERCELL DAY.

.DSM...NONE

SEARCY

The office that day

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

Issued	Product	Office	Counties	Lasted
May 18, 10:23 AM CDT	Severe Thunderstorm Warning	DMX	Story	22 min
May 18, 10:34 AM CDT	Tornado Warning	DMX	Adair, Cass	21 min
May 18, 10:39 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Hardin, Story	31 min
May 18, 10:39 AM CDT	Severe Thunderstorm Warning	DMX	Grundy, Marshall	31 min
May 18, 10:49 AM CDT	Severe Thunderstorm Warning	DMX	Dallas	31 min
May 18, 10:54 AM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Grundy, Tama	31 min
May 18, 11:00 AM CDT	Tornado Warning	DMX	Audubon, Cass	30 min
May 18, 11:10 AM CDT	Severe Thunderstorm Warning	DMX	Dickinson	10 min
May 18, 11:19 AM CDT	Severe Thunderstorm Warning	DMX	Dallas, Madison, Polk, Warren	46 min
May 18, 11:27 AM CDT	Severe Thunderstorm Warning	DMX	Wapello	28 min
May 18, 11:27 AM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	28 min
May 18, 11:36 AM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	29 min
May 18, 11:51 AM CDT	Tornado Warning	DMX	Polk, Warren	29 min
May 18, 12:07 PM CDT	Tornado Warning	DMX	Jasper, Marion	28 min
May 18, 12:36 PM CDT	Severe Thunderstorm Warning	DMX	Jasper	29 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2000 Every severe thunderstorm warning in 2000

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.