Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 294, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Sep 1, 1998, 4:03 PM CDT for Palo Alto County, Iowa. It was in force for 32 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
- Sep 1, 1998, 4:03 PM CDT (21:03 UTC)
- Expired
- Sep 1, 1998, 4:35 PM CDT
- In force
- 32 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Palo Alto County, IA
The radar
The Des Moines radar (KDMX), 169 km from the middle of the area, began a volume at 21:04 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 |
|---|---|---|---|
| Sep 1, 4:05 PM CDT | Hail 0.75 | Ruthven, IA | |
| Sep 1, 4:15 PM CDT | Hail 0.75 | Emmetsburg, 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
Minneapolis, MN (KMPX), launched 12:00Z, 9.1 hours before the alert went out and 215 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
- 16 J/kg
- Mixed-layer CIN
- -372 J/kg
- Mixed-layer LCL
- 1649 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 92 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
530 WUUS1 KDSM 012104 RRA SVRDSM IAC147-012135- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE DES MOINES IA 403 PM CDT TUE SEP 1 1998 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... PALO ALTO COUNTY IN NORTHWESTERN IOWA * UNTIL 435 PM CDT * AT 401 PM CDT... THE PUBLIC REPORTED A SEVERE THUNDERSTORM 16 MILES EAST SOUTHEAST OF SPENCER OR 1 MILE NORTH NORTHWEST OF AYRSHIRE MOVING SOUTHEAST AT 25 MPH. * THIS STORM CAN BE EXPECTED NEAR... AYRSHIRE NOW CURLEW BY 417 PM CDT MALLARD BY 428 PM CDT THIS STORM HAS A HISTORY OF LARGE HAIL. GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS FILLBACH
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, Sep 1, 10:25 AM CDT, 5 hours 38 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020200- CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTION FRO TYPOS NATIONAL WEATHER SERVICE DES MOINES IA 1025 AM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--SOUTHEAST OF A MASON CITY-CARROLL LINE. TIMING DETAILS--NOON UNTIL 600 PM NORTH OF HIGHWAY 30...AND 300 PM UNTIL 900 PM SOUTH OF HIGHWAY 30. METEOROLOGICAL COMMENTS--A STRONG COLD FRONT EXTENDING FROM CENTRAL WISCONSIN INTO NORTHWEST NEBRASKA WILL MOVE ACROSS THE STATE THIS AFTERNOON. WINDS WERE BEGINNING TO PILE MOISTURE UP ALONG THE FRONT AND AS THE AFTERNOON WEARS ON...THE COMBINATION OF INCREASING MOISTURE AND TEMPERATURES WILL CAUSE A NARROW LINE OF THUNDERSTORMS TO DEVELOP. AREAL COVERAGE WILL NOT BE GREAT AND MANY AREAS WILL NOT SEE ANY RAIN AT ALL. HOWEVER BECAUSE OF THE RAPID COOLING OCCURRING IN THE MID LEVELS OF THE ATMOSPHERE...ANY STORM THAT DEVELOPS WILL BE ABLE TO PRODUCE SMALL HAIL AND GUSTY DOWNBURST WINDS. ONCE THE SUN SETS THIS EVENING...THE STORMS WILL LOSE THEIR ENERGY AND WILL GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO AS THE FRONT PASSES. MONITOR SHORT TERM FORECASTS AND FUTURE OUTLOOKS FOR DETAILS. THERE IS A REMOTE CHANCE THAT ONE OR TWO STORMS WILL BRIEFLY BECOME SEVERE...WITH LARGE HAIL THE MAIN THREAT IF THEY DO. PYTLAK
Special weather statement, Sep 1, 10:25 AM CDT, 5 hours 38 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020200- CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTION FRO TYPOS NATIONAL WEATHER SERVICE DES MOINES IA 1025 AM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--SOUTHEAST OF A MASON CITY-CARROLL LINE. TIMING DETAILS--NOON UNTIL 600 PM NORTH OF HIGHWAY 30...AND 300 PM UNTIL 900 PM SOUTH OF HIGHWAY 30. METEOROLOGICAL COMMENTS--A STRONG COLD FRONT EXTENDING FROM CENTRAL WISCONSIN INTO NORTHWEST NEBRASKA WILL MOVE ACROSS THE STATE THIS AFTERNOON. WINDS WERE BEGINNING TO PILE MOISTURE UP ALONG THE FRONT AND AS THE AFTERNOON WEARS ON...THE COMBINATION OF INCREASING MOISTURE AND TEMPERATURES WILL CAUSE A NARROW LINE OF THUNDERSTORMS TO DEVELOP. AREAL COVERAGE WILL NOT BE GREAT AND MANY AREAS WILL NOT SEE ANY RAIN AT ALL. HOWEVER BECAUSE OF THE RAPID COOLING OCCURRING IN THE MID LEVELS OF THE ATMOSPHERE...ANY STORM THAT DEVELOPS WILL BE ABLE TO PRODUCE SMALL HAIL AND GUSTY DOWNBURST WINDS. ONCE THE SUN SETS THIS EVENING...THE STORMS WILL LOSE THEIR ENERGY AND WILL GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO AS THE FRONT PASSES. MONITOR SHORT TERM FORECASTS AND FUTURE OUTLOOKS FOR DETAILS. THERE IS A REMOTE CHANCE THAT ONE OR TWO STORMS WILL BRIEFLY BECOME SEVERE...WITH LARGE HAIL THE MAIN THREAT IF THEY DO. PYTLAK
Special weather statement, Sep 1, 3:10 PM CDT, 53 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020400- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 310 PM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--ALL OF CENTRAL IOWA. TIMING DETAILS--THROUGH 900 PM. METEOROLOGICAL COMMENTS--A LINE OF ISOLATED THUNDERSTORMS HAS DEVELOPED FROM SOUTHEAST WISCONSIN INTO FAR NORTHWEST IOWA AHEAD OF THE STRONG COLD FRONT DROPPING INTO THE STATE. MOISTURE CONVERGENCE ALONG THE FRONT REMAINS WEAK BUT DEWPOINTS HAVE CLIMBED INTO THE MID TO UPPER 60S...RESULTING IN RATHER STRONG INSTABILITY. MID LEVEL STEERING WINDS HAVE ALSO INCREASED TO 40 TO 45 MPH WHILE AT THE SAME TIME MID LEVEL TEMPERATURES COOLED. THE COMBINATION OF ALL THESE FACTORS WILL ALLOW ANY STORMS THAT DEVELOP TO PRODUCE SMALL HAIL AND GUSTY WINDS. ONCE THE SUN SETS THIS EVENING...THE WEAK CONVERGENCE AND LOSS OF DAYTIME HEATING WILL CAUSE THE STORMS TO GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO THIS EVENING AS THIS LINE COMES THROUGH. COVERAGE WILL BE VERY SPOTTY...HOWEVER. EVEN IF A THUNDERSTORM DOES NOT PASS DIRECTLY OVERHEAD...LIGHTNING CAN STRIKE MANY MILES AWAY FROM IT. AS SOON AS YOU HEAR THUNDER...MOVE INDOORS. PYTLAK
Special weather statement, Sep 1, 3:10 PM CDT, 53 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020400- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 310 PM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--ALL OF CENTRAL IOWA. TIMING DETAILS--THROUGH 900 PM. METEOROLOGICAL COMMENTS--A LINE OF ISOLATED THUNDERSTORMS HAS DEVELOPED FROM SOUTHEAST WISCONSIN INTO FAR NORTHWEST IOWA AHEAD OF THE STRONG COLD FRONT DROPPING INTO THE STATE. MOISTURE CONVERGENCE ALONG THE FRONT REMAINS WEAK BUT DEWPOINTS HAVE CLIMBED INTO THE MID TO UPPER 60S...RESULTING IN RATHER STRONG INSTABILITY. MID LEVEL STEERING WINDS HAVE ALSO INCREASED TO 40 TO 45 MPH WHILE AT THE SAME TIME MID LEVEL TEMPERATURES COOLED. THE COMBINATION OF ALL THESE FACTORS WILL ALLOW ANY STORMS THAT DEVELOP TO PRODUCE SMALL HAIL AND GUSTY WINDS. ONCE THE SUN SETS THIS EVENING...THE WEAK CONVERGENCE AND LOSS OF DAYTIME HEATING WILL CAUSE THE STORMS TO GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO THIS EVENING AS THIS LINE COMES THROUGH. COVERAGE WILL BE VERY SPOTTY...HOWEVER. EVEN IF A THUNDERSTORM DOES NOT PASS DIRECTLY OVERHEAD...LIGHTNING CAN STRIKE MANY MILES AWAY FROM IT. AS SOON AS YOU HEAR THUNDER...MOVE INDOORS. PYTLAK
Special weather statement, Sep 1, 3:31 PM CDT, 32 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020400- CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTION NATIONAL WEATHER SERVICE DES MOINES IA 331 PM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--ALL OF CENTRAL IOWA. TIMING DETAILS--THROUGH 900 PM. METEOROLOGICAL COMMENTS--A LINE OF ISOLATED THUNDERSTORMS HAS DEVELOPED FROM SOUTHWEST WISCONSIN INTO FAR NORTHWEST IOWA AHEAD OF THE STRONG COLD FRONT DROPPING INTO THE STATE. MOISTURE CONVERGENCE ALONG THE FRONT REMAINS WEAK BUT DEWPOINTS HAVE CLIMBED INTO THE MID TO UPPER 60S...RESULTING IN RATHER STRONG INSTABILITY. MID LEVEL STEERING WINDS HAVE ALSO INCREASED TO 40 TO 45 MPH WHILE AT THE SAME TIME MID LEVEL TEMPERATURES COOLED. THE COMBINATION OF ALL THESE FACTORS WILL ALLOW ANY STORMS THAT DEVELOP TO PRODUCE SMALL HAIL AND GUSTY WINDS. ONCE THE SUN SETS THIS EVENING...THE WEAK CONVERGENCE AND LOSS OF DAYTIME HEATING WILL CAUSE THE STORMS TO GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO THIS EVENING AS THIS LINE COMES THROUGH. COVERAGE WILL BE VERY SPOTTY...HOWEVER. EVEN IF A THUNDERSTORM DOES NOT PASS DIRECTLY OVERHEAD...LIGHTNING CAN STRIKE MANY MILES AWAY FROM IT. AS SOON AS YOU HEAR THUNDER...MOVE INDOORS. PYTLAK CORRECTION FOR THUNDERSTORM LOCATION IN MET COMMENTS SECTION
Special weather statement, Sep 1, 3:31 PM CDT, 32 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-020400- CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTION NATIONAL WEATHER SERVICE DES MOINES IA 331 PM CDT TUE SEP 1 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS...A FEW OF WHICH WILL PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 45 MPH. AREA OF CONCERN--ALL OF CENTRAL IOWA. TIMING DETAILS--THROUGH 900 PM. METEOROLOGICAL COMMENTS--A LINE OF ISOLATED THUNDERSTORMS HAS DEVELOPED FROM SOUTHWEST WISCONSIN INTO FAR NORTHWEST IOWA AHEAD OF THE STRONG COLD FRONT DROPPING INTO THE STATE. MOISTURE CONVERGENCE ALONG THE FRONT REMAINS WEAK BUT DEWPOINTS HAVE CLIMBED INTO THE MID TO UPPER 60S...RESULTING IN RATHER STRONG INSTABILITY. MID LEVEL STEERING WINDS HAVE ALSO INCREASED TO 40 TO 45 MPH WHILE AT THE SAME TIME MID LEVEL TEMPERATURES COOLED. THE COMBINATION OF ALL THESE FACTORS WILL ALLOW ANY STORMS THAT DEVELOP TO PRODUCE SMALL HAIL AND GUSTY WINDS. ONCE THE SUN SETS THIS EVENING...THE WEAK CONVERGENCE AND LOSS OF DAYTIME HEATING WILL CAUSE THE STORMS TO GRADUALLY DISSIPATE. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED FOR AN HOUR OR TWO THIS EVENING AS THIS LINE COMES THROUGH. COVERAGE WILL BE VERY SPOTTY...HOWEVER. EVEN IF A THUNDERSTORM DOES NOT PASS DIRECTLY OVERHEAD...LIGHTNING CAN STRIKE MANY MILES AWAY FROM IT. AS SOON AS YOU HEAR THUNDER...MOVE INDOORS. PYTLAK CORRECTION FOR THUNDERSTORM LOCATION IN MET COMMENTS SECTION
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 1, 4:29 PM CDT | Severe Thunderstorm Warning | DMX | Pocahontas | 31 min |
| Sep 1, 5:16 PM CDT | Severe Thunderstorm Warning | DMX | Pocahontas | 34 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 1998Every severe thunderstorm warning in 1998
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.