Alert archive / Iowa / Tornado Warnings in 1999
Tornado Warning 30, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at May 16, 1999, 8:17 PM CDT for Boone County, Story County, Iowa. It was in force for 33 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, 1999, 8:17 PM CDT (01:17 UTC)
- Expired
- May 16, 1999, 8:50 PM CDT
- In force
- 33 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Boone County, IA, Story County, IA
The radar
The Des Moines radar (KDMX), 34 km from the middle of the area, began a volume at 01:16 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 |
|---|---|---|---|
| May 16, 8:29 PM CDT | Hail 2.75 | Boone, IA | |
| May 16, 8:52 PM CDT | Tornado F0 | Ames, 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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 16, 3:00 PM CDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.3 hours before the alert went out and 236 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
- 996 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 781 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 261 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 10.2
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KDSM 170117 RRA TORDSM IAC015-169-170150- BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE DES MOINES IA 817 PM CDT SUN MAY 16 1999 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * TORNADO WARNING FOR... BOONE COUNTY IN CENTRAL IOWA STORY COUNTY IN CENTRAL IOWA * UNTIL 850 PM CDT * AT 815 PM CDT... DOPPLER RADAR INDICATED A TORNADO 33 MILES SOUTH SOUTHEAST OF FORT DODGE OR 2 MILES WEST NORTHWEST OF MOINGONA... MOVING EAST AT 30 MPH. * THIS TORNADO CAN BE EXPECTED NEAR... MOINGONA BY 819 PM CDT BOONE BY 822 PM CDT AMES BY 840 PM CDT GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR! JJ/JAW
What forecasters said that day
The local office's own words before this tornado 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 tornado warning went out at May 16, 6:27 PM CDT, 1 hour 50 minutes earlier.
Area forecast discussion, May 16, 6:27 PM CDT, 1 hour 50 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 628PM CDT SUN MAY 16 1999 RAINFALL RATES GETTING OUT OF HAND SO ALTHOUGH ITS A LTL LATE HAVE DECIDED TO ISSUE FLASH FLOOD WATCH FOR THE ENTIRE CWA OVNGT. MAIN TSTM COMPLEX TWRD MO RVR HAS YET TO REACH FA AND WITH CONVECTION LINING UP INTO KS...SGFNT TRAINING MAY TAKE PLACE. .DSM...FLASH FLOOD WATCH TNGT ENTIRE DMX FA. SMALL
In the hours before
Special weather statement, May 16, 2:24 PM CDT, 5 hours 53 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-162000- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 224 PM CDT SUN MAY 16 1999 HAZARD--SEVERE THUNDERSTORMS PRODUCING LARGE HAIL...DAMAGING WINDS AND POSSIBLY TORNADOES. HEAVY RAINS ARE ALSO LIKELY. AREA OF CONCERN--ALL OF THE DES MOINES NATIONAL WEATHER SERVICE WARNING AREA. TIMING DETAILS--THUNDERSTORMS COULD RAPIDLY DEVELOP AT ANY TIME ACROSS EASTERN NEBRASKA OR EXTREME WESTERN IOWA AND THEN MOVE TOWARD INTERSTATE 35 LATER THIS AFTERNOON OR EARLY THIS EVENING. SOUTHEASTERN SECTIONS NEAR OTTUMWA WILL HAVE THE BEST CHANCES FOR THUNDERSTORMS TONIGHT. THE THUNDERSTORMS OVER NORTHEAST IOWA NEAR WATERLOO SHOULD END BY 300 OR 400 PM WITH MORE STORMS POSSIBLE THIS EVENING. METEOROLOGICAL COMMENTS--A COLD FRONT WAS POSITIONED FROM CENTRAL KANSAS TOWARD THE MISSOURI RIVER NEAR WEST CENTRAL IOWA THIS AFTERNOON AND WAS SLOWLY MOVING INTO IOWA. THE AIRMASS EAST OF THE FRONT WAS VERY UNSTABLE AND WITH LITTLE CAP OR WARM AIR ALOFT TO PROHIBIT DEVELOPMENT...SEVERE THUNDERSTORMS COULD RAPIDLY FORM AT ANY TIME AND QUICKLY BECOME SEVERE. THE COMBINATION OF ADEQUATE WIND SHEAR LEVELS AND HIGH INSTABILITY WILL MAKE THE ENVIRONMENT CONDUCIVE FOR DAMAGING WINDS AND MORE LARGE HAIL. OUTFLOW BOUNDARIES FROM EARLIER THUNDERSTORMS AND THE AFOREMENTIONED WIND SHEAR COULD ALSO CAUSE TORNADOES TO DEVELOP IN THE STRONGER STORMS. WITH SURFACE DEWPOINTS IN THE 70S MOVING INTO WESTERN IOWA...THE STORMS COULD ALSO PRODUCE HEAVY RAINS AND POSSIBLE FLOODING. PRECAUTIONS--SEVERE WEATHER WATCHES COULD BE ISSUED AT ANY TIME ACROSS WESTERN IOWA. SPOTTER ACTIVATION WILL LIKELY BE NEEDED LATER THIS AFTERNOON AND TONIGHT. PEOPLE WITH OUTDOOR CONCERNS SHOULD PAY CLOSE ATTENTION TO FUTURE STATEMENTS...WATCHES AND WARNING. THE WEATHER CONDITIONS COULD CHANGE QUICKLY SO BE PREPARED TO TAKE ACTION. SMALL
Local storm report, May 16, 3:10 PM CDT, 5 hours 7 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
310 PM CDT SUN MAY 16 1999
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1145 AM WOOLSTOCK IA .75 INCH HAIL
05/16/99 WRIGHT
1201 PM POPEJOY IA .75 INCH HAIL
05/16/99 FRANKLIN
1203 PM ROWAN IA 1.25 INCH HAIL
05/16/99 WRIGHT
1212 PM HAMPTON IA 1 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1223 PM 2 NE HANSELL IA 1.75 INCH HAIL
05/16/99 FRANKLIN
1230 PM 4 SE ALLISON IA 1 INCH HAIL
05/16/99 BUTLER
1248 PM 2 S BRISTOW IA .75 INCH HAIL
05/16/99 BUTLER
1251 PM 2 E PLAINFIELD IA 1.75 INCH HAIL
05/16/99 BREMER
1253 PM 5 SE HANSELL IA 1 INCH HAIL
05/16/99 FRANKLIN
0105 PM 7 E PLAINFIELD IA 1.75 INCH HAIL
05/16/99 BREMER
0121 PM 7 SW ALLISON IA .75 INCH HAIL
05/16/99 BUTLER
0130 PM PARKERSBURG IA .75 INCH HAIL
05/16/99 BUTLER
0150 PM 4 SW SUMNER IA 1 INCH HAIL
05/16/99 BREMER
0221 PM 5 N WATERLOO IA .75 INCH HAIL
05/16/99 BLACKHAWKLocal storm report, May 16, 3:10 PM CDT, 5 hours 7 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
310 PM CDT SUN MAY 16 1999
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1145 AM WOOLSTOCK IA .75 INCH HAIL
05/16/99 WRIGHT
1201 PM POPEJOY IA .75 INCH HAIL
05/16/99 FRANKLIN
1203 PM ROWAN IA 1.25 INCH HAIL
05/16/99 WRIGHT
1212 PM HAMPTON IA 1 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1221 PM 2 E DOWS IA .75 INCH HAIL
05/16/99 FRANKLIN
1223 PM 2 NE HANSELL IA 1.75 INCH HAIL
05/16/99 FRANKLIN
1230 PM 4 SE ALLISON IA 1 INCH HAIL
05/16/99 BUTLER
1248 PM 2 S BRISTOW IA .75 INCH HAIL
05/16/99 BUTLER
1251 PM 2 E PLAINFIELD IA 1.75 INCH HAIL
05/16/99 BREMER
1253 PM 5 SE HANSELL IA 1 INCH HAIL
05/16/99 FRANKLIN
0105 PM 7 E PLAINFIELD IA 1.75 INCH HAIL
05/16/99 BREMER
0121 PM 7 SW ALLISON IA .75 INCH HAIL
05/16/99 BUTLER
0130 PM PARKERSBURG IA .75 INCH HAIL
05/16/99 BUTLER
0150 PM 4 SW SUMNER IA 1 INCH HAIL
05/16/99 BREMER
0221 PM 5 N WATERLOO IA .75 INCH HAIL
05/16/99 BLACKHAWKSpecial weather statement, May 16, 7:01 PM CDT, 1 hour 16 minutes before
IAZ057-058-070-071-170015- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 701 PM CDT SUN MAY 16 1999 ...TORNADO WARNING UNTIL 725 PM FOR CASS AND AUDUBON COUNTIES... AT 7 PM RADAR INDICATED SEVERE THUNDERSTORMS EXTENDING ACROSS MOST OF CASS COUNTY INTO EASTERN AUDUBON COUNTY. LARGE HAIL HAS BEEN REPORTED WITH THESE STORMS. ALTHOUGH RADAR INDICATES THE ROTATION IN THESE STORMS HAS DECREASED... THESE STORMS MAY PRODUCE A TORNADO AT ANY TIME. JW
Special weather statement, May 16, 7:01 PM CDT, 1 hour 16 minutes before
IAZ057-058-070-071-170015- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 701 PM CDT SUN MAY 16 1999 ...TORNADO WARNING UNTIL 725 PM FOR CASS AND AUDUBON COUNTIES... AT 7 PM RADAR INDICATED SEVERE THUNDERSTORMS EXTENDING ACROSS MOST OF CASS COUNTY INTO EASTERN AUDUBON COUNTY. LARGE HAIL HAS BEEN REPORTED WITH THESE STORMS. ALTHOUGH RADAR INDICATES THE ROTATION IN THESE STORMS HAS DECREASED... THESE STORMS MAY PRODUCE A TORNADO AT ANY TIME. JW
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 7:35 PM CDT | Flash Flood Warning | DMX | Black Hawk | 115 min |
| May 16, 7:44 PM CDT | Tornado Warning | DMX | Boone, Dallas | 31 min |
| May 16, 7:52 PM CDT | Severe Thunderstorm Warning | DMX | Dallas, Madison, Polk, Warren | 48 min |
| May 16, 7:54 PM CDT | Flash Flood Warning | DMX | Bremer | 3 hr |
| May 16, 8:16 PM CDT | Flash Flood Warning | DMX | Cass | 3 hr |
| May 16, 8:36 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marshall | 49 min |
| May 16, 8:44 PM CDT | Tornado Warning | DMX | Hamilton, Story | 31 min |
| May 16, 9:00 PM CDT | Tornado Warning | DMX | Hardin | 50 min |
| May 16, 9:43 PM CDT | Flash Flood Warning | DMX | Black Hawk | 77 min |
| May 16, 10:02 PM CDT | Flash Flood Warning | DMX | Butler | 3 hr |
| May 17, 8:47 AM CDT | Flash Flood Warning | DMX | Black Hawk | 6 hr |
Nearby
Tornado Warnings in Iowa, 1999Every tornado warning in 1999Tornadoes 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.