Alert archive / Iowa / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 451, NWS Des Moines, IA

September 17, 2004Hamilton County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Sep 17, 2004, 7:18 PM CDT for Hamilton County, Iowa. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 17, 2004, 7:18 PM CDT (00:18 UTC)
Expired: Sep 17, 2004, 8:00 PM CDT
In force: 42 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Hamilton County, IA

The radar

The Des Moines radar (KDMX), 76 km from the middle of the area, began a volume at 00:21 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.3 hours before the alert went out and 247 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2056 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 118 m²/s²
0-3 km storm-relative helicity: 217 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.

000 
WUUS53 KDMX 180018
SVRDMX
IAC079-180100-
/X.NEW.KDMX.SV.W.0016.040918T0018Z-040918T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
718 PM CDT FRI SEP 17 2004

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  HAMILTON COUNTY IN CENTRAL IOWA.

* UNTIL 800 PM CDT.

* AT 717 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL.  THIS
  STORM WAS LOCATED 7 MILES SOUTH OF WEBSTER CITY...OR 23 MILES
  SOUTHEAST OF FORT DODGE...AND MOVING SOUTHEAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  NEAR JEWELL BY 735 PM CDT.
  NEAR ELLSWORTH BY 740 PM CDT.
  NEAR RANDALL BY 745 PM CDT.

THE LOCATIONS OF KAMRAR AND STANHOPE ARE ALSO IN THE PATH OF THIS
SEVERE THUNDERSTORM.

LARGE HAIL CAN CAUSE INJURY AND PROPERTY DAMAGE. SEEK SAFETY INDOORS
UNTIL THE STORM PASSES.

REPORT TORNADOES...WIND IN EXCESS OF 50 MPH...HAIL LARGER THAN ONE
HALF INCH...OR STORM DAMAGE TO YOUR NATIONAL WEATHER SERVICE IN DES
MOINES AT 1-800-759-9276.

LAT...LON 4255 9396 4221 9393 4222 9350 4254 9351

$$

KINNEY

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.

NWS Des Moines, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 17, 3:30 PM CDT, 3 hours 48 minutes earlier.

Area forecast discussion, Sep 17, 3:30 PM CDT, 3 hours 48 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
330 PM CDT FRI SEP 17 2004

.DISCUSSION...
SHORT TERM PROBLEMS ABOUND AND CENTER AROUND CONVECTION CHANCES
OVERNIGHT AND THEN AGAIN SATURDAY NIGHT. SOME TIMING PROBLEMS STILL
EXIST WITH THE NEXT FRONT TO MOVE THROUGH THE AREA THE MIDDLE OF
NEXT WEEK. NO MAJOR CHANGES TO FORECAST OTHER THAN POPS IN THE SHORT
TERM. CURRENT ELEVATED CONVECTIVE CLUSTER OVER NW IOWA WITH MARGINAL
SEVERE HAIL CONTINUES TO REDEVELOP ON THE WESTERN EDGE AIDED BY
DECREASING LOW LEVEL JET AND STRONG THETA-E ADVECTION. LEADING EDGE
OF THE ELEVATED INSTABILITY AXIS IS NOW EDGING INTO THE CENTRAL CWA.
HAVE NOTED ON THE PROFILER NETWORK THAT THE H850 WINDS OVER NE
NEBRASKA ARE FINALLY STARTING TO DECREASE. THESE STRONGER WINDS...40
KTS...PERSISTED MUCH LONGER THAN MODELS INDICATED. THE CONVECTION
OVER NORTHERN IOWA SHOULD SLOWLY DIMINISH THIS EVENING AS IT MOVES
FURTHER EAST INTO MORE STABLE AIR. AM MORE TROUBLED WITH THE
SOUTHERN CONVECTION OVER WEST CENTRAL IOWA. MODELS CONTINUE TO PROG
INTENSIFYING LOW LEVEL JET THIS EVENING OVER NE KS INTO S IA WITH
GOOD SPEED CONFLUENCE AND ELEVATED MOISTURE TRANSPORT OVER THE
SOUTHERN PORTION OF THE STATE. AM NOT SURE WHETHER OR NOT THE
EXISTING CONVECTION WILL DIMINISH AND THEN REDEVELOP LATER THIS
EVENING OR IF IT WILL JUST CONTINUE TO BUILD SE THROUGH THE
AFTERNOON AND EVENING. WILL KEEP HIGHER POPS OVER THE EASTERN CWA
AFTER MIDNIGHT AS BEST THETA-E CONVERGENCE MOVES EAST. AREA WILL
REMAIN IN BUILDING UPPER RIDGE OVER THE WEEKEND WITH STRENGTHENING
SOUTHERLY FLOW. STRONG NIGHTTIME LOW LEVEL JET WILL ALLOW SOME
MIXING AND HOLD TEMPS UP INTO THE  60S OVER MOST AREAS. MORE WEAK
FORCING SATURDAY NIGHT WITH GFS AND NOW THE 18Z ETA PRODUCING SOME
LIGHT QPF OVER E IA. WILL BROADBRUSH THE EAST WITH LOW CHC POPS AS
CONFIDENCE IS NOT HIGH. HAVE MADE MINOR ADJUSTMENTS TO PCPN CHANCES
TUES THRU THURS. MODELS ARE NOW A BIT FASTER IN LIFTING THE MAIN
UPPER TROUGH NE. WITH MORE TIMING ADJUSTMENTS SURE TO COME THE NEXT
FEW DAYS...HAVE ONLY MADE SLIGHT ADJUSTMENTS TO TIMING BUT HAVE
BOOSTED POPS AS MODELS MAINTAIN GOOD POST FRONTAL PCPN AS TROUGH
LIFTS TOWARD THE AREA. OVERALL HAVE TRENDED ON THE COOL SIDE OF MOS
TEMPS AS SURFACE WINDS NEVER COME AROUND TO THE SW. IF THEY
DO...H850 TEMPS AND WINDS WOULD SUPPORT MORE WIDESPREAD MID/UPPER
80S THAN IS FORECAST.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

JAW

Hazardous weather outlook, Sep 17, 3:30 PM CDT, 3 hours 48 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
330 PM CDT FRI SEP 17 2004

IAZ004>007-015>017-023>028-181100-
BREMER-BUTLER-CERRO GORDO-EMMET-FRANKLIN-HANCOCK-HUMBOLDT-KOSSUTH-
PALO ALTO-POCAHONTAS-WINNEBAGO-WORTH-WRIGHT-
330 PM CDT FRI SEP 17 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN IOWA
ALONG AND NORTH OF HIGHWAY 3.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL SLOWLY DIMINISH OVER NORTHERN IOWA THIS
EVENING. ISOLATED PENNY TO NICKEL SIZE HAIL WILL OCCUR WITH THE
STORMS. IN ADDITION...ISOLATED 2 TO 3 INCH RAINFALL AMOUNTS WILL
OCCUR. THIS MAY PRODUCE ISOLATED FLASH FLOODING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY THROUGH THURSDAY.  IT
IS TOO EARLY TO ASSESS THE SEVERE POTENTIAL OF THE STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS EVENING.

IAZ033>039-044>050-057>062-070>075-181100-
ADAIR-AUDUBON-BLACK HAWK-BOONE-CALHOUN-CARROLL-CASS-CRAWFORD-DALLAS-
GREENE-GRUNDY-GUTHRIE-HAMILTON-HARDIN-JASPER-MADISON-MAHASKA-MARION-
MARSHALL-POLK-POWESHIEK-SAC-STORY-TAMA-WARREN-WEBSTER-
330 PM CDT FRI SEP 17 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA ALONG
AND SOUTH OF HIGHWAY 20...AND ALONG AND NORTH OF HIGHWAY 92.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL MOVE ACROSS PORTIONS OF CENTRAL AND
SOUTHERN IOWA TONIGHT. ISOLATED PENNY TO NICKEL SIZE HAIL WILL OCCUR
WITH THE STORMS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY EVENING THROUGH
THURSDAY.  IT IS TOO EARLY TO ASSESS THE SEVERE POTENTIAL OF THE
STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE TONIGHT.

IAZ081>086-092>097-181100-
ADAMS-APPANOOSE-CLARKE-DAVIS-DECATUR-LUCAS-MONROE-RINGGOLD-TAYLOR-
UNION-WAPELLO-WAYNE-
330 PM CDT FRI SEP 17 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHERN IOWA ALONG
AND SOUTH OF HIGHWAY 34.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP AND MOVE ACROSS SOUTHERN IOWA
TONIGHT. ISOLATED PENNY TO NICKEL SIZE HAIL IS POSSIBLE WITH THE
STRONGER STORMS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE OF THUNDERSTORMS LATE TUESDAY NIGHT THROUGH
THURSDAY.  IT IS TOO EARLY TO ASSESS THE SEVERE POTENTIAL OF THE
STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH THE WEEKEND.

JAW

In the hours before

Local storm report, Sep 17, 3:16 PM CDT, 4 hours 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
316 PM CDT FRI SEP 17 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0300 PM     HAIL             2 N HAVELOCK            42.86N 94.70W
09/17/2004  0.88 INCH        POCAHONTAS         IA   LAW ENFORCEMENT

&&

COGIL

Local storm report, Sep 17, 5:38 PM CDT, 1 hour 40 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
538 PM CDT FRI SEP 17 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0443 PM     TSTM WND GST     BARNUM                  42.51N 94.36W
09/17/2004  58 MPH           WEBSTER            IA   MESONET

            KCCI SCHOOLNET

0500 PM     HAIL             1 N LOHRVILLE           42.27N 94.54W
09/17/2004  1.00 INCH        CALHOUN            IA   TRAINED SPOTTER

0514 PM     HAIL             2 S FARNHAMVILLE        42.25N 94.42W
09/17/2004  1.00 INCH        CALHOUN            IA   TRAINED SPOTTER

0533 PM     HAIL             6 S CALLENDER           42.28N 94.29W
09/17/2004  0.75 INCH        WEBSTER            IA   TRAINED SPOTTER

&&

COGIL

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 1:20 AM CDT	Severe Thunderstorm Warning	DMX	Taylor	40 min
Sep 18, 2:16 AM CDT	Severe Thunderstorm Warning	DMX	Taylor	44 min
Sep 18, 2:29 AM CDT	Flash Flood Warning	DMX	Taylor	6 hr
Sep 18, 2:40 AM CDT	Severe Thunderstorm Warning	DMX	Adams	50 min
Sep 18, 3:11 AM CDT	Flash Flood Warning	DMX	Adams	6 hr
Sep 18, 4:10 AM CDT	Severe Thunderstorm Warning	DMX	Adams	50 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2004 Every severe thunderstorm warning in 2004

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.