Alert archive / Iowa / Severe Thunderstorm Warnings in 1996
Severe Thunderstorm Warning 71, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 1996, 7:58 PM CDT for Sac County, Iowa. It was in force for 42 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
- Jun 20, 1996, 7:58 PM CDT (00:58 UTC)
- Expired
- Jun 20, 1996, 8:40 PM CDT
- In force
- 42 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 01:01 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Jun 20, 8:14 PM CDT | Hail 0.75 | Early, 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 00:00Z, 1.0 hours before the alert went out and 158 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.
- Mixed-layer CAPE
- 2363 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 1424 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 112 m²/s²
- 0-3 km storm-relative helicity
- 276 m²/s²
- Significant tornado parameter
- 2.1
- Supercell composite
- 19.6
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDSM 210058
SVRDSM
IAC161-210140-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
758 PM CDT THU JUN 20 1996
* SEVERE THUNDERSTORM WARNING FOR
NORTHERN SAC COUNTY - WEST CENTRAL IOWA
* UNTIL 840 PM CDT
* SOME LOCATIONS AFFECTED
NEMAHA
EARLY
SAC CITY
* AT 755 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM 5 MILES NORTH
OF EARLY...OR 45 MILES SOUTH OF SPENCER MOVING EAST AT 25 MPH.
* THE STORM WILL BE JUST NORTH OF SAC CITY AROUND 815 PM.
THIS IS A DANGEROUS STORM. DO NOT GO OUTDOORS. A TORNADO WATCH IS
ALSO IN EFFECT. SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES.
SMALLWhat 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, Jun 20, 2:54 PM CDT, 5 hours 4 minutes before
IAZ004>006-015-016-023>025-033>036-044>048-057>060-070>073-081>083- 092>094-202230- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 255 PM CDT THU JUN 20 1996 HAZARD...SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING WIND GUSTS TO 75 MPH...HAIL ONE INCH IN DIAMETER...AND ISOLATED RAINFALL AMOUNTS OF 2 TO 3 INCHES. AREA OF CONCERN...WESTERN HALF OF IOWA...ALONG AND WEST OF A LAMONI TO DES MOINES TO LAKE MILLS LINE. TIMING DETAILS...LATE THIS AFTERNOON ACROSS FAR NORTHWEST IOWA AND THIS EVENING AND TONIGHT OVER CENTRAL AND NORTHERN IOWA. METEOROLOGICAL COMMENTS...A STATIONARY FRONT LOCATED ACROSS NORTHEAST THROUGH SOUTHWEST IOWA WILL CONTINUE TO BE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON INTO TONIGHT. AN UPPER LEVEL DISTURBANCE IS FORECAST TO PUSH OUT OF THE ROCKIES AND INTO THE PLAINS LATE THIS AFTERNOON AND INTERACT WITH AN EXTREMELY UNSTABLE AIRMASS ACROSS EASTERN NEBRASKA. THUNDERSTORMS WERE ALREADY OCCURRING OVER PARTS OF NORTHEAST NEBRASKA INTO NORTHWEST IOWA AND FURTHER DEVELOPMENT IS ANTICIPATED LATER THIS AFTERNOON AS THE UPPER LEVEL DISTURBANCE MOVES EAST. LOW LEVEL WIND PROFILES ACROSS WESTERN IOWA ARE EXPECTED TO BECOME MORE FAVORABLE FOR SUPERCELL DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS THE DISTURBANCE INTERACTS WITH THE STATIONARY FRONTAL SYSTEM LYING ACROSS THE STATE. LATEST VISIBLE SATELLITE PICTURES INDICATE SKIES WERE CLEARING ACROSS PARTS OF SOUTHWEST IOWA WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE EVEN FURTHER LATER THIS AFTERNOON. LIFTED INDICES ACROSS EASTERN NEBRASKA WERE ALREADY RANGING FROM -10 TO -15 INDICATING EXTREME INSTABILITY PRESENT IN THIS AREA. THUNDERSTORMS WILL INTENSIFY ACROSS NORTHWEST IOWA LATE THIS AFTERNOON WITH ADDITIONAL DEVELOPMENT EXPECTED FURTHER SOUTH INTO FAR WEST AND SOUTHWEST IOWA BY THIS EVENING. IN ADDITION TO THE THREAT FOR LARGE HAIL AND ISOLATED TORNADOES...THERE ALSO EXISTS THE REAL THREAT OF ADDITIONAL HEAVY RAINFALL...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE. PRESENT INDICATIONS SUGGEST THE POTENTIAL FOR UP TO 3 INCHES OF RAIN ACROSS EXTREME NORTHERN IOWA LATER TONIGHT INTO FRIDAY MORNING. FURTHER SOUTH...RAINFALL AMOUNTS WILL RANGE FROM ONE HALF TO ONE INCH WHICH WILL FURTHER AGGRAVATE THE ALREADY SATURATED SOIL CONDITIONS. PRECAUTIONS...SPOTTER ACTIVATION IS LIKELY LATER THIS AFTERNOON INTO TONIGHT. EMERGENCY MANAGERS AND WATER RESOURCE PERSONNEL SHOULD KEEP ABREAST OF THE SITUATION. SMITH
Special weather statement, Jun 20, 2:57 PM CDT, 5 hours 1 minute before
IAZ004>006-015-016-023>025-033>036-044>048-057>060-070>073-081>083- 092>094-202230- CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTION NATIONAL WEATHER SERVICE DES MOINES IA 255 PM CDT THU JUN 20 1996 HAZARD...SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING WIND GUSTS TO 75 MPH...HAIL ONE INCH IN DIAMETER...AND ISOLATED RAINFALL AMOUNTS OF 2 TO 3 INCHES. AREA OF CONCERN...WESTERN HALF OF IOWA...ALONG AND WEST OF A LAMONI TO DES MOINES TO LAKE MILLS LINE. TIMING DETAILS...LATE THIS AFTERNOON ACROSS FAR NORTHWEST IOWA AND THIS EVENING AND TONIGHT OVER CENTRAL AND NORTHERN IOWA. METEOROLOGICAL COMMENTS...A STATIONARY FRONT LOCATED ACROSS NORTHEAST THROUGH SOUTHWEST IOWA WILL CONTINUE TO BE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON INTO TONIGHT. AN UPPER LEVEL DISTURBANCE IS FORECAST TO PUSH OUT OF THE ROCKIES AND INTO THE PLAINS LATE THIS AFTERNOON AND INTERACT WITH AN EXTREMELY UNSTABLE AIRMASS ACROSS EASTERN NEBRASKA. THUNDERSTORMS WERE ALREADY OCCURRING OVER PARTS OF NORTHEAST NEBRASKA INTO NORTHWEST IOWA AND FURTHER DEVELOPMENT IS ANTICIPATED LATER THIS AFTERNOON AS THE UPPER LEVEL DISTURBANCE MOVES EAST. LOW LEVEL WIND PROFILES ACROSS WESTERN IOWA ARE EXPECTED TO BECOME MORE FAVORABLE FOR SUPERCELL DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS THE DISTURBANCE INTERACTS WITH THE STATIONARY FRONTAL SYSTEM LYING ACROSS THE STATE. LATEST VISIBLE SATELLITE PICTURES INDICATE SKIES WERE CLEARING ACROSS PARTS OF SOUTHWEST IOWA WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE EVEN FURTHER LATER THIS AFTERNOON. LIFTED INDICES ACROSS EASTERN NEBRASKA WERE ALREADY RANGING FROM -10 TO -15 INDICATING EXTREME INSTABILITY PRESENT IN THIS AREA. THUNDERSTORMS WILL INTENSIFY ACROSS NORTHWEST IOWA LATE THIS AFTERNOON WITH ADDITIONAL DEVELOPMENT EXPECTED FURTHER SOUTH INTO FAR WEST AND SOUTHWEST IOWA BY THIS EVENING. IN ADDITION TO THE THREAT FOR LARGE HAIL AND ISOLATED TORNADOES...THERE ALSO EXISTS THE REAL THREAT OF ADDITIONAL HEAVY RAINFALL...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE. PRESENT INDICATIONS SUGGEST THE POTENTIAL FOR UP TO 3 INCHES OF RAIN ACROSS EXTREME NORTHERN IOWA LATER TONIGHT INTO FRIDAY MORNING. FURTHER SOUTH...RAINFALL AMOUNTS WILL RANGE FROM ONE HALF TO ONE INCH WHICH WILL FURTHER AGGRAVATE THE ALREADY SATURATED SOIL CONDITIONS. PRECAUTIONS...SPOTTER ACTIVATION IS LIKELY LATER THIS AFTERNOON INTO TONIGHT. EMERGENCY MANAGERS AND WATER RESOURCE PERSONNEL SHOULD KEEP ABREAST OF THE SITUATION. SMITH
Special weather statement, Jun 20, 4:04 PM CDT, 3 hours 54 minutes before
IAZ004>006-015-016-023>025-033>036-044>048-057>060-070>073-081>083- 092>094-202230- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 410 PM CDT THU JUN 20 1996 HAZARD...SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DOWNBURST WIND GUSTS TO 75 MPH...ISOLATED TORNADOES...HAIL ONE INCH IN DIAMETER...AND ISOLATED RAINFALL AMOUNTS OF 2 TO 3 INCHES. AREA OF CONCERN...NORTHWEST THIRD OF IOWA THIS EVENING...NORTHWEST OF AN ALGONA TO DENISON LINE. OVER WESTERN AND NORTHERN IOWA LATE THIS EVENING AND TONIGHT...ALONG AND WEST OF A LAMONI TO DES MOINES TO LAKE MILLS LINE. TIMING DETAILS...THIS EVENING ACROSS NORTHWEST IOWA AND OVERNIGHT FOR CENTRAL AND NORTHERN IOWA. METEOROLOGICAL COMMENTS...A STATIONARY FRONT LOCATED ACROSS NORTHEAST THROUGH SOUTHWEST IOWA WILL CONTINUE TO BE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON INTO TONIGHT. AN UPPER LEVEL DISTURBANCE IS FORECAST TO PUSH OUT OF THE ROCKIES AND INTO THE PLAINS LATE THIS AFTERNOON AND INTERACT WITH AN EXTREMELY UNSTABLE AIRMASS ACROSS EASTERN NEBRASKA. THUNDERSTORMS WERE ALREADY OCCURRING OVER PARTS OF NORTHEAST NEBRASKA INTO NORTHWEST IOWA AND FURTHER DEVELOPMENT IS ANTICIPATED LATER THIS AFTERNOON AS THE UPPER LEVEL DISTURBANCE MOVES EAST. LOW LEVEL WIND PROFILES ACROSS WESTERN IOWA ARE EXPECTED TO BECOME MORE FAVORABLE FOR SUPERCELL DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS THE DISTURBANCE INTERACTS WITH THE STATIONARY FRONTAL SYSTEM LYING ACROSS THE STATE. LATEST VISIBLE SATELLITE PICTURES INDICATE SKIES CONTINUING TO CLEAR OVER PARTS OF SOUTHWEST AND CENTRAL IOWA WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE EVEN FURTHER THIS EVENING. LIFTED INDICES ACROSS EASTERN NEBRASKA WERE ALREADY RANGING FROM -10 TO -15 INDICATING EXTREME INSTABILITY PRESENT IN THIS AREA. STRONG THUNDERSTORMS ALREADY OCCURRING OVER NORTHWEST IOWA WILL CONTINUE TO PUSH EASTWARD THIS EVENING WHILE ADDITIONAL STORM DEVELOPMENT IS EXPECTED FURTHER SOUTH INTO FAR WEST AND SOUTHWEST IOWA THIS EVENING. IN ADDITION TO THE THREAT FOR LARGE HAIL AND ISOLATED TORNADOES...THERE ALSO EXISTS THE THREAT OF ADDITIONAL HEAVY RAINFALL...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE. PRESENT INDICATIONS SUGGEST THE POTENTIAL FOR UP TO 3 INCHES OF RAIN ACROSS EXTREME NORTHERN IOWA LATER TONIGHT INTO FRIDAY MORNING. FURTHER SOUTH...RAINFALL AMOUNTS WILL RANGE FROM ONE HALF TO ONE INCH WHICH WILL FURTHER AGGRAVATE THE ALREADY SATURATED SOIL CONDITIONS. PRECAUTIONS...SPOTTER ACTIVATION IS LIKELY THIS EVENING AND TONIGHT. EMERGENCY MANAGERS AND WATER RESOURCE PERSONNEL SHOULD KEEP ABREAST OF THE SITUATION. SMITH
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 8:13 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Pocahontas | 32 min |
| Jun 21, 1:04 AM CDT | Severe Thunderstorm Warning | DMX | Crawford | 26 min |
| Jun 21, 1:30 AM CDT | Severe Thunderstorm Warning | DMX | Calhoun | 30 min |
| Jun 21, 4:10 AM CDT | Flash Flood Warning | DMX | Crawford | 3 hr |
| Jun 21, 4:13 AM CDT | Flash Flood Warning | DMX | Carroll, Crawford | 3 hr |
| Jun 21, 6:47 AM CDT | Flash Flood Warning | DMX | Crawford | 3 hr |
Nearby
Severe Thunderstorm Warnings in Iowa, 1996Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.