Alert archive / Iowa / Tornado Warnings in 2008
Tornado Warning 121, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at Jul 21, 2008, 3:17 AM CDT for Polk County, Iowa. It was in force for 28 min. 9 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 21, 2008, 3:17 AM CDT (08:17 UTC)
- Expired
- Jul 21, 2008, 3:45 AM CDT
- In force
- 28 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
County Polk County, IA
The radar
The Des Moines radar (KDMX), 15 km from the middle of the area, began a volume at 08:18 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 |
|---|---|---|---|
| Jul 21, 3:18 AM CDT | TSTM WND DMG | Polk City, IA | 18 INCH TREES DOWN. |
| Jul 21, 3:18 AM CDT | HAIL 0.88 | Polk City, IA | |
| Jul 21, 3:21 AM CDT | TSTM WND DMG | 1 Ene Johnston, IA | 1 FOOT DIAMETER TREE BRANCH OVER ROAD. ROAD UNKNOWN. |
| Jul 21, 3:21 AM CDT | TSTM WND GST 70 | 3 S Polk City, IA | 70 MPH AT NWS OFFICE WITH SMALL HAIL. STRONG WIND LASTING 5 MINUTES AND STILL ON GOING. |
| Jul 21, 3:22 AM CDT | TSTM WND DMG | Ankeny, IA | NUMEROUS 4 TO 6 INCH TREE BRANCHES DOWN IN TOWN. 1 14 INCH TREE BRANCH DOWN. ESTIMATED POWER OUT TO 50 PERCENT OF TOWN. AMATEUR RADIO REPORT. |
| Jul 21, 3:25 AM CDT | TSTM WND DMG | 6 Wnw Ankeny Airport, IA | 20 TO 30 BLACK LOCUST TREES...1 TO 2 FEET IN DIAMETER AND ABOUT 50 TO 60 FEET TALL WERE SNAPPED OFF AND/OR UPROOTED FROM A RESIDENTS 1 ACRE PLOT OF LAND...AT THE INTERSECTION OF NW 35TH STREET AND HIGHWAY 415. TWO LARGE TREES DOWN ON TOP OF HOUSE...DAMAGE UNKN |
| Jul 21, 3:25 AM CDT | HAIL 0.75 | 5 Nnw Ankeny Airport, IA | |
| Jul 21, 3:28 AM CDT | TSTM WND GST 70 | Nw Ankeny, IA | |
| Jul 21, 3:35 AM CDT | TSTM WND GST 61 | Ankeny, IA | FROM IOWA DOT RWIS |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jul 20, 11:25 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 8.3 hours before the alert went out and 240 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
- 3989 J/kg
- Mixed-layer CIN
- -58 J/kg
- Mixed-layer LCL
- 1202 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 91 m²/s²
- 0-3 km storm-relative helicity
- 306 m²/s²
- Significant tornado parameter
- 3.7
- Supercell composite
- 26.4
The text
As transmitted, in the capitals the NWS used until 2016.
000 WFUS53 KDMX 210817 TORDMX IAC153-210845- /O.NEW.KDMX.TO.W.0121.080721T0817Z-080721T0845Z/ BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE DES MOINES IA 317 AM CDT MON JUL 21 2008 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * TORNADO WARNING FOR... NORTHERN POLK COUNTY IN CENTRAL IOWA... * UNTIL 345 AM CDT. * AT 314 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 6 MILES WEST OF POLK CITY...OR 19 MILES NORTHWEST OF DES MOINES...MOVING EAST AT 67 MPH. * THE TORNADO WILL BE NEAR... POLK CITY AND JOHNSTON BY 320 AM CDT... ANKENY...SAYLORVILLE AND ALLEMAN BY 325 AM CDT... BONDURANT...ANKENY AIRPORT...ALTOONA AND ELKHART BY 330 AM CDT... THIS INCLUDES INTERSTATE 80 BETWEEN MILE MARKERS 139 AND 148. THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 88 AND 102. THIS IS A HAZARDOUS SITUATION. SEEK SHELTER IN A BASEMENT...OR IN AN INTERIOR ROOM. STAY AWAY FROM WINDOWS. IF YOU ARE OUTSIDE OR IN A CAR...SEEK SHELTER IN A REINFORCED BUILDING. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 AM CDT MONDAY MORNING FOR IOWA. LAT...LON 4162 9336 4169 9382 4186 9382 4186 9336 TIME...MOT...LOC 0817Z 287DEG 58KT 4178 9377 $$
1 follow-up statement
000 WWUS53 KDMX 210827 SVSDMX SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 327 AM CDT MON JUL 21 2008 IAC153-210845- /O.CON.KDMX.TO.W.0121.000000T0000Z-080721T0845Z/ POLK IA- 327 AM CDT MON JUL 21 2008 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 345 AM CDT FOR NORTHERN POLK COUNTY... AT 322 AM CDT...WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM WITH STRONG ROTATION. THIS TORNADO WAS LOCATED NEAR POLK CITY...OR 13 MILES NORTH OF DES MOINES...MOVING EAST AT 67 MPH. THE TORNADO WILL BE NEAR... RURAL EASTERN POLK COUNTY AT 340 AM CDT THIS INCLUDES INTERSTATE 80 BETWEEN MILE MARKERS 139 AND 148. THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 88 AND 102. SEEK SHELTER IN A BASEMENT...OR IN AN INTERIOR ROOM. STAY AWAY FROM WINDOWS. IF YOU ARE IN A CAR OR OUTSIDE...SEEK SHELTER IN A REINFORCED BUILDING. IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING NICKEL HAIL HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS OF 80 MPH. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 AM CDT MONDAY MORNING FOR IOWA. LAT...LON 4162 9336 4169 9382 4186 9382 4186 9336 TIME...MOT...LOC 0827Z 287DEG 58KT 4173 9356 $$
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 1:09 AM CDT | Severe Thunderstorm Warning | DMX | Dallas, Polk | 51 min |
| Jul 21, 1:10 AM CDT | Severe Thunderstorm Warning | DMX | Carroll, Crawford, Sac | 65 min |
| Jul 21, 1:15 AM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marion | 45 min |
| Jul 21, 1:33 AM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marion, Polk, Warren | 42 min |
| Jul 21, 1:47 AM CDT | Flash Flood Warning | DMX | Crawford, Sac | 4 hr |
| Jul 21, 1:54 AM CDT | Areal Flood Advisory | DMX | Calhoun, Humboldt, Pocahontas, Webster | 3 hr |
| Jul 21, 2:00 AM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Marion | 45 min |
| Jul 21, 2:03 AM CDT | Severe Thunderstorm Warning | DMX | Audubon, Calhoun, Carroll, Greene, Guthrie | 57 min |
| Jul 21, 2:10 AM CDT | Tornado Warning | DMX | Calhoun, Carroll, Sac | 50 min |
| Jul 21, 2:19 AM CDT | Severe Thunderstorm Warning | DMX | Boone, Greene | 41 min |
| Jul 21, 2:20 AM CDT | Flash Flood Warning | DMX | Carroll | 3 hr |
| Jul 21, 2:33 AM CDT | Severe Thunderstorm Warning | DMX | Boone, Dallas, Greene, Guthrie, Polk, Story | 57 min |
| Jul 21, 2:39 AM CDT | Flash Flood Warning | DMX | Mahaska | 4 hr |
| Jul 21, 2:48 AM CDT | Tornado Warning | DMX | Boone, Dallas, Greene | 42 min |
| Jul 21, 2:51 AM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Wapello | 27 min |
| Jul 21, 3:06 AM CDT | Severe Thunderstorm Warning | DMX | Marshall, Story | 54 min |
| Jul 21, 3:14 AM CDT | Severe Thunderstorm Warning | DMX | Madison, Marion, Polk, Warren | 61 min |
| Jul 21, 3:16 AM CDT | Severe Thunderstorm Warning | DMX | Wapello | 17 min |
| Jul 21, 3:21 AM CDT | Areal Flood Advisory | DMX | Boone, Dallas, Greene, Jasper, Polk, Story | 3 hr |
| Jul 21, 3:22 AM CDT | Severe Thunderstorm Warning | DMX | Jasper | 53 min |
| Jul 21, 3:53 AM CDT | Areal Flood Advisory | DMX | Jasper, Madison, Marshall, Story, Warren | 8 days |
| Jul 21, 3:53 AM CDT | Severe Thunderstorm Warning | DMX | Jasper, Lucas, Mahaska, Marion, Monroe, Poweshiek and 1 more | 67 min |
| Jul 21, 4:05 AM CDT | Severe Thunderstorm Warning | DMX | Marshall, Tama | 40 min |
Nearby
Tornado Warnings in Iowa, 2008Every tornado warning in 2008Tornadoes in 2008
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.