Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 22, NWS Des Moines, IA

May 16, 1997Union County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 16, 1997, 6:37 PM CDT for Union County, Iowa. It was in force for 48 min. 2 reports 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, 1997, 6:37 PM CDT (23:37 UTC)
Expired
May 16, 1997, 7:25 PM CDT
In force
48 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Union County, IA

The radar

The Des Moines radar (KDMX), 89 km from the middle of the area, began a volume at 23:40 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, 6:50 PM CDTHail 1Afton, IA
May 16, 7:07 PM CDTHail 0.75Lorimor, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 16, 5:00 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.6 hours before the alert went out and 181 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, Omaha, NE at 12:00Z on 1997-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 12:00Z on 1997-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 square meters per square second.193958Sfc1 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
2709 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
271 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.

503 
WUUS1 KDSM 162338 RRA
SVRDSM
IAC175-170025-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
637 PM CDT FRI MAY 16 1997

* SEVERE THUNDERSTORM WARNING FOR
  UNION COUNTY - SOUTH CENTRAL IOWA

* UNTIL 725 PM CDT
 
* SOME AREAS AFFECTED
    CRESTON
    AFTON
    LORIMAR
    THAYER

* AT AT 630 PM CDT STORM SPOTTERS REPORTED A SEVERE THUNDERSTORM 15
  MILES NORTH OF CRESTON OR 50 MILES SOUTHWEST OF DES MOINES MOVING
  SOUTHEAST AT 40 MPH.

* THE STORM WILL BE NEAR AFTON BY 655 PM.

THIS IS A DANGEROUS STORM.  DO NOT GO OUTDOORS.

STARK

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 16, 2:20 PM CDT, 4 hours 17 minutes before
IAZ004-005-015-023-024-033>035-044>046-057-058-070-071-081>086-
092>097-170115-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
222 PM CDT FRI MAY 16 1997

HAZARD--WIDELY SCATTERED THUNDERSTORMS.  A FEW COULD PRODUCE LARGE
HAIL AND WIND GUSTS OVER 55 MPH.

AREAS OF CONCERN--WESTERN AND SOUTHERN IOWA...SOUTH AND WEST OF AN
ALGONA...TO ADAIR...TO CHARITON LINE.

TIMING DETAILS--DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
STARTING AFTER 300 PM AND LASTING UNTIL AROUND 800 PM.

METEOROLOGICAL COMMENTS--BREEZY SOUTHWEST WINDS WERE WARMING UP
TEMPERATURES ACROSS IOWA BUT WERE ALSO INCREASING MOISTURE
LEVELS...ESPECIALLY OVER WESTERN PORTIONS OF THE STATE.  BY LATE THIS
AFTERNOON LOW LEVEL MOISTURE MAY INCREASE ENOUGH TO PRODUCE WEAK
INSTABILITY AND ALLOW WIDELY SCATTERED SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS WESTERN AND SOUTHWEST IOWA.  EVEN THOUGH THE MOISTURE
WILL INCREASE SOME...IT WILL STILL BE RELATIVELY DRY IN THE LOW LEVELS
OF THE ATMOSPHERE SO GUSTY WINDS WOULD BE THE PRIMARY THREAT.
WIDESPREAD SHOWERS AND STORMS ARE NOT EXPECTED HOWEVER...SO MOST SPOTS
SHOULD NOT BE AFFECTED.

PRECAUTIONS--NO ACTIONS NEED TO BE TAKEN AT THIS TIME.  HOWEVER PEOPLE
WITH OUTDOOR ACTIVITIES PLANNED LATE THIS AFTERNOON AND EARLY THIS
EVENING SHOULD MONITOR THE LATEST SHORT TERM FORECASTS AND OUTLOOKS
FOR UPDATED INFORMATION.

SMALL
Special weather statement, May 16, 2:22 PM CDT, 4 hours 15 minutes before
IAZ004-005-015-023-024-033>035-044>046-057-058-070-071-081>086-
092>097-170115-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
222 PM CDT FRI MAY 16 1997

HAZARD--WIDELY SCATTERED THUNDERSTORMS.  A FEW COULD PRODUCE LARGE
HAIL AND WIND GUSTS OVER 55 MPH.

AREAS OF CONCERN--WESTERN AND SOUTHERN IOWA...SOUTH AND WEST OF AN
ALGONA...TO ADAIR...TO CHARITON LINE.

TIMING DETAILS--DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
STARTING AFTER 300 PM AND LASTING UNTIL AROUND 800 PM.

METEOROLOGICAL COMMENTS--BREEZY SOUTHWEST WINDS WERE WARMING UP
TEMPERATURES ACROSS IOWA BUT WERE ALSO INCREASING MOISTURE
LEVELS...ESPECIALLY OVER WESTERN PORTIONS OF THE STATE.  BY LATE THIS
AFTERNOON LOW LEVEL MOISTURE MAY INCREASE ENOUGH TO PRODUCE WEAK
INSTABILITY AND ALLOW WIDELY SCATTERED SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS WESTERN AND SOUTHWEST IOWA.  EVEN THOUGH THE MOISTURE
WILL INCREASE SOME...IT WILL STILL BE RELATIVELY DRY IN THE LOW LEVELS
OF THE ATMOSPHERE SO GUSTY WINDS WOULD BE THE PRIMARY THREAT.
WIDESPREAD SHOWERS AND STORMS ARE NOT EXPECTED HOWEVER...SO MOST SPOTS
SHOULD NOT BE AFFECTED.

PRECAUTIONS--NO ACTIONS NEED TO BE TAKEN AT THIS TIME.  HOWEVER PEOPLE
WITH OUTDOOR ACTIVITIES PLANNED LATE THIS AFTERNOON AND EARLY THIS
EVENING SHOULD MONITOR THE LATEST SHORT TERM FORECASTS AND OUTLOOKS
FOR UPDATED INFORMATION.

SMALL
Special weather statement, May 16, 6:35 PM CDT, 2 minutes before
IAZ034>039-044>049-057-058-170100

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
635 PM CDT FRI MAY 16 1997

...PARTIAL CLEARANCE OF SEVERE THUNDERSTORM WATCH NUMBER 287...

THE FOLLOWING COUNTIES HAVE BEEN CLEARED FROM SEVERE THUNDERSTORM
WATCH NUMBR 287.

CALHOUN - WEBSTER - HAMILTON - HARDIN - GRUNDY - BLACK HAWK
CRAWFORD - CARROLL - GREENE - BOONE - STORY - MARSHALL - AUDUBON
AND GUTHRIE.

THE STRONG TO SEVERE THUNDERSTORMS HAVE MOVED SOUTHEAST OF THE AREA.
THOUGH SCATTERED SHOWERS WILL PASS THROUGH THE AREA DURING THE NEXT
TWO HOURS...SEVERE STORMS ARE NOT EXPECTED.
Special weather statement, May 16, 6:36 PM CDT, 1 minute before
IAZ034>039-044>049-057-058-170100

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
635 PM CDT FRI MAY 16 1997

...PARTIAL CLEARANCE OF SEVERE THUNDERSTORM WATCH NUMBER 287...

THE FOLLOWING COUNTIES HAVE BEEN CLEARED FROM SEVERE THUNDERSTORM
WATCH NUMBR 287.

CALHOUN - WEBSTER - HAMILTON - HARDIN - GRUNDY - BLACK HAWK
CRAWFORD - CARROLL - GREENE - BOONE - STORY - MARSHALL - AUDUBON
AND GUTHRIE.

THE STRONG TO SEVERE THUNDERSTORvMS HAVE MOVED SOUTHEAST OF THE AREA.
THOUGH SCATTERED SHOWERS WILL PASS THROUGH THE AREA DURING THE NEXT
TWO HOURS...SEVERE STORMS ARE NOT EXPECTED.

The office that day

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

IssuedProductOfficeCountiesLasted
May 16, 5:32 PM CDTSevere Thunderstorm WarningDMXBoone, Polk33 min
May 16, 5:38 PM CDTSevere Thunderstorm WarningDMXDallas32 min
May 16, 6:02 PM CDTSevere Thunderstorm WarningDMXAdair33 min
May 16, 6:58 PM CDTSevere Thunderstorm WarningDMXRinggold, Taylor47 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1997Every severe thunderstorm warning in 1997

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.