Alert archive / Iowa / Severe Thunderstorm Warnings in 1996

Severe Thunderstorm Warning 33, NWS Des Moines, IA

May 17, 1996Calhoun County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 17, 1996, 11:16 PM CDT for Calhoun County, 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: May 17, 1996, 11:16 PM CDT (04:16 UTC)
Expired: May 17, 1996, 11:50 PM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Whole counties

County Calhoun County, IA

The radar

The Des Moines radar (KDMX), 105 km from the middle of the area, began a volume at 04:19 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

Omaha, NE (KOAX), launched 00:00Z, 4.3 hours before the alert went out and 186 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: 3864 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 1845 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: -24 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 180416
SVRDSM
IAC025-180450-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1116 PM CDT FRI MAY 17 1996

* SEVERE THUNDERSTORM WARNING FOR
  EASTERN CALHOUN COUNTY - WEST CENTRAL IOWA

* UNTIL 1150 PM CDT
 
* SOME LOCATIONS AFFECTED
    KNIERIM
    SOMERS

* AT 1105 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM 20 MILES
  SOUTHWEST OF FORT DODGE NEAR HIGHWAY 20 MOVING NORTHEAST AT 40 MPH.

* THE STORM WILL BE NEAR SOMERS AT 1115 PM.

THIS IS A DANGEROUS STORM.  DO NOT GO OUTDOORS.

 A TORNADO WATCH IS ALSO IN EFFECT.  SEVERE THUNDERSTORMS CAN
PRODUCE TORNADOES.

FELDT

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.

In the hours before

Special weather statement, May 17, 8:24 PM CDT, 2 hours 52 minutes before

IAZALL-180330-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
824 PM CDT FRI MAY 17 1996

HAZARD...SEVERE THUNDERSTORMS WITH DAMAGING WINDS OF 60 MPH OT
GREATER AND LARGE HAIL - UP TO THREE DIAMETER.  ISOLATED TORNADOES
ARE POSSIBLE.

AREA OF CONCERN...GREATEST AREA OF CONCERN UNTIL 11 PM CDT IS WEST
OF A LINE FROM SHENANDOAH TO FORT DODGE TO MASON CITY.  CENTRAL
PORTION OF THE STATE COULD RECEIVE ISOLATED DAMAGING WINDS AFTER 9
PM CDT.

TIMING DETAILS...STORMS IN WEST CENTRAL IOWA WILL MOVE NORTHEAST
THROUGH THE AREA OF GREAT CONCERN AND INTO NORTH CENTRAL IOWA BEFORE
MIDNIGHT.  STORMS IN CENTRAL IOWA ARE NOT EXPECTED UNTIL AFTER 9 PM
CDT OR LATER.

METEOROLOGICAL COMMENTS...VERY UNSTABLE AIR REMAINS OVER THE STATE
HOWEVER VERY WARM AIR ALOFT IS KEEPING MUCH OF THE AREAS CAPPED AND
INHIBITING DEVELOPMENT.  HOWEVER AS A COLD FRONT PUSHES INTO FARTHER
INTO THE STATE THIS CAP WILL BE OVERCOME AND DEVELOPMENT IS LIKELY.
AT THE SAME TIME A FAIRLY STRONG JET WILL TRACK OVER THE AREA AND
FURTHER ENHANCE THE LIKELIHOOD OF DEVELOPMENT DESPITE THE TIME OF
DAY.  UPPER LEVEL WINDS CONTINUE TO SHOW WEAK DYNAMICS FAVORABLE
FOR TORNADIC DEVELOPMENT.  INSTEAD THE WIND PROFILE FAVORS DAMGING
STRAIGHT LINE WINDS.

PRECAUTIONS...EMERGENCY MANAGERS MAY CONTINUE TO MONITOR THE LATEST
FORECASTS AND STATEMENTS OUTSIDE THE WATCH AREA.  INSIDE THE WATCH
AREA COUNTIES IN WEST CENTRAL IOWA CAN EXPECT STORMS OVER THE NEXT
FEW HOURS.

Special weather statement, May 17, 10:12 PM CDT, 1 hour 4 minutes before

IAZ004>007-015>017-023>028-035-180345-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1012 PM CDT FRI MAY 17 1996

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN WEBSTER COUNTY
WILL EXPIRE AT 1020 PM...

THE SEVERE THUNDERSTORM THAT PRODUCED GOLF BALL SIZE HAIL IN
SOUTHWEST WEBSTER COUNTY HAD DECREASED IN INTENSITY AS OF 1015 PM.
THE SEVERE THUNDERSTORM WARNING FOR WEBSER COUNTY WILL EXPIRE AT
1020 PM.

FELDT

The office that day

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

Issued	Product	Office	Counties	Lasted
May 17, 8:30 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	50 min
May 17, 8:50 PM CDT	Severe Thunderstorm Warning	DMX	Audubon	50 min
May 17, 9:51 PM CDT	Severe Thunderstorm Warning	DMX	Webster	29 min
May 17, 10:53 PM CDT	Severe Thunderstorm Warning	DMX	Sac	32 min
May 17, 11:05 PM CDT	Severe Thunderstorm Warning	DMX	Webster	30 min
May 17, 11:50 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Wright	35 min
May 18, 12:11 AM CDT	Severe Thunderstorm Warning	DMX	Franklin	34 min
May 18, 12:31 AM CDT	Severe Thunderstorm Warning	DMX	Floyd	44 min
May 18, 12:38 AM CDT	Severe Thunderstorm Warning	DMX	Butler	32 min
May 18, 12:59 AM CDT	Severe Thunderstorm Warning	DMX	Chickasaw, Howard	46 min
May 18, 1:21 AM CDT	Severe Thunderstorm Warning	DMX	Winneshiek	39 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1996 Every severe thunderstorm warning in 1996

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.