Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 378, NWS Des Moines, IA

October 21, 2001Decatur County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Oct 21, 2001, 4:12 PM CDT for Decatur County, Iowa. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Oct 21, 2001, 4:12 PM CDT (21:12 UTC)
Expired: Oct 21, 2001, 5:00 PM CDT
In force: 48 min
Issued by: NWS Des Moines, IA
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Decatur County, IA

The radar

The Des Moines radar (KDMX), 107 km from the middle of the area, began a volume at 21:15 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.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.2 hours before the alert went out and 221 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: 1657 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: -85 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

436 
WUUS53 KDMX 212112
SVRDSM
IAC053-212200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
412 PM CDT SUN OCT 21 2001

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  DECATUR COUNTY IN SOUTH CENTRAL IOWA

* UNTIL 500 PM CDT

* AT 410 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 10 MILES NORTH OF LAMONI...OR ABOUT 59 MILES
  SOUTH OF DES MOINES...MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  NEAR LEON AROUND 430 PM

HAIL UP TO THE SIZE OF QUARTERS IS LIKELY IN THE WARNED AREA.

SEEK A STURDY SHELTER SUCH AS A BASEMENT OR INTERIOR ROOM.

LAT...LON 4090 9402 4059 9401 4059 9357 4090 9358

COGIL

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 Oct 21, 3:00 PM CDT, 1 hour 12 minutes earlier.

Area forecast discussion, Oct 21, 3:00 PM CDT, 1 hour 12 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
300 PM CDT SUN OCT 21 2001

IN THE SHORTER TERM MAIN FORECAST PROBLEM IS PRECIPITATION POTENTIAL
SUNDAY NIGHT...TIMING OF END OF PRECIPITATION EARLY TUESDAY...AND
THEN PRECIPITATION POTENTIAL ONCE AGAIN WEDNESDAY MORNING...THE
FIRST AND LAST EVENTS WHICH WE CURRENTLY HAVE A DRY FORECAST GOING.

SOME MODEL DIFFERENCES IN HOW QUICKLY THE ATMOSPHERE SATURATES
THROUGH THE COLUMN LATE SUNDAY NIGHT AND MONDAY. AVN ALSO QUICKER IN
LIFTING PRECIPITATION INTO N IA ON MONDAY. CERTAINLY AT THIS POINT
NEARLY IMPOSSIBLE TO KNOW WHICH MODEL IS CORRECT.

ASPECTS OF TODAYS FORECAST LOOKS VERY SIMILAR TO YESTERDAYS. WEAK
SHORTWAVE TROUGH PASSING THROUGH THE DAKOTAS AND MINNESOTA HAS
HELPED TO SPREAD ABUNDANT MID/HIGH LEVEL MOISTURE ACROSS THE STATE.
SOME WEAK ECHOS SHOWING UP ON RADAR WITH 10 MILE -RA ON A FEW SE SD
SFC OBS. A FEW SPRINKLES MAY BRUSH THE NORTHERN PORTION OF THE CWA
THIS MORNING. WILL WAIT TO RELEASE TIME BEFORE DECIDING WHETHER OR
NOT TO MENTION IN ZONES. MOST WEAK MID LEVEL QG SUPPORT WILL PASS TO
THE NE OF THE AREA BY 18Z WITH A SMATTERING OF CLOUDS AND SUN
EXPECTED THROUGH THE AFTERNOON.

MAIN FORECAST CHALLENGE THEN BECOMES PRECIPITATION POSSIBILITIES
LATER SUNDAY NIGHT AS FAIRLY STRONG LOW/MID LEVEL WARM/MOIST AIR
ADVECTION KICKS IN IN ADVANCE OF SHORT WAVE LIFTING NE INTO THE
PLAINS. TRAJECTORIES ON THE 295K AND 300K SURFACES INDICATE
100-130MB OF POTENTIAL LIFT ACROSS THE STATE BY 12Z MONDAY. QUESTION
IS WILL ATMOSPHERE SATURATE BY 12Z MONDAY. CERTAINLY BEST POTENTIAL
WILL REMAIN NEAR THE MO BORDER WHERE SATURATION PRESS DEFICITS LOWER
TO ABOUT 30MB. LOOKS LIKE THERE WILL BE NO PROBLEM WITH SURFACE
MOISTURE AS 50 AND 60 DEGREES DEW POINTS OVER KS AND MO EAGERLY
AWAIT THERE RETURN TO THE MIDWEST ON MONDAY. MODELS DO DIFFER IN THE
DEPTH AND MAGNITUDE OF AN ELEVATED DRY LAYER SUNDAY NIGHT. IT IS
THIS LAYER THAT WILL DICTATE WHETHER OR NOT PRECIPITATION MAKES IT
TO THE GROUND AS LIFT AND THETA-E CONVERGENCE/ADVECTION APPEAR
ADEQUATE. WILL STILL KEEP SOUTHERN ZONES DRY AS THE ISENTROPICS
INDICATE SATURATION WILL NOT BE ACHIEVED. WILL BE CLOSE HOWEVER AND
DAY SHIFT CAN DECIDE ON INCLUSION OF NIGHTTIME POPS.

DURING THE DAY MONDAY AND MONDAY NIGHT LIKELY POPS STILL SEEM IN
ORDER. THOUGH THERE IS A LACK OF ANY GOOD JET SUPPORT...DIFFLUENT
UPPER LEVEL FLOW WILL AID IN UVM. THIS COUPLED WITH A GOOD MOISTURE
SUPPLY AND SOME INSTABILITY WILL RESULT IN SCATTERED TO WIDESPREAD
SHOWERS AND THUNDERSTORMS. MODELS NOW BRING FRONT THROUGH MONDAY
NIGHT AND IT LOOKS LIKE TUESDAY COULD END OF BEING DRY OVER MOST OF
THE AREA. WILL DELETE MENTION OF MORNING POPS IN THE WEST ON TUESDAY.

AVN IS SHOWING ANOTHER STRONG SHORT WAVE TROUGH TO ROTATE THROUGH
THE REGION ON WEDNESDAY. IF THIS DOES VERIFY...SOME RAIN WOULD
SPREAD BACK INTO THE AREA BY 12Z WEDNESDAY. DAY SHIFT WILL ALSO NEED
TO ASSESS NEW MODEL RUNS FOR POSSIBLE INCLUSION OF POPS TUESDAY
NIGHT AND OR WEDNESDAY. STILL LOOKING CHILLY THURS AND FRI.

.DSM...NONE

JAW

In the hours before

Special weather statement, Oct 21, 3:34 PM CDT, 38 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
334 PM CDT SUN OCT 21 2001

.A WARM FRONT OVER NORTHERN MISSOURI WILL BEGIN TO LIFT NORTH
TONIGHT.  RELATIVELY WARM MOIST AIR MOVING NORTH INTO IOWA TONIGHT
AND MONDAY WILL CAUSE SCATTERED THUNDERSTORMS TO DEVELOP. THE
GREATEST THREAT FROM THESE STORMS WILL BE HAIL WITH A SECONDARY WIND
THREAT DURING THE DAY AND EVENING MONDAY.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070-071-221100-
ADAIR-AUDUBON-BLACK
HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CASS-CERRO
GORDO-CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-
HANCOCK-HARDIN-HUMBOLDT-JASPER-KOSSUTH-MARSHALL-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-SAC-STORY-TAMA-WEBSTER-WINNEBAGO-
WORTH-WRIGHT-
INCLUDING THE CITIES OF...ALGONA...AMES...ATLANTIC...BOONE...
CARROLL...DENISON...DES MOINES...ESTHERVILLE...FORT DODGE...
GRINNELL...IOWA FALLS...MARSHALLTOWN...MASON CITY...NEWTON...PERRY...
WATERLOO...WAVERLY AND WEBSTER CITY
334 PM CDT SUN OCT 21 2001

...HEADLINE WITH ANY NON-CONVECTIVE WATCHES...WARNINGS OR ADVISORIES
IN EFFECT...

THREAT                         PROBABILITY      EVENT TIMING
------                         -----------      ------------

THUNDERSTORMS
  TORNADO                         NONE.
  DAMAGING WINDS (58+ MPH)        LOW.         9 AM MON - 12 AM TUE.
  LARGE HAIL (3/4+)              LOW.         5 AM MON - 12 AM TUE.
  FLASH FLOODING                  NONE.

* SPOTTER ACTIVATION OUTLOOK      LOW.         6 AM MON - 12 AM TUE.

* THE THREAT OF THUNDERSTORMS WILL BE GREATEST OVER SOUTHERN IOWA
MONDAY MORNING AND THEN SPREAD NORTH INTO NORTHERN IOWA MONDAY
AFTERNOON AND EVENING.

IAZ072>075-081>085-092>096-221100-
ADAMS-APPANOOSE-CLARKE-DECATUR-LUCAS-MADISON-MAHASKA-MARION-MONROE-
RINGGOLD-TAYLOR-UNION-WARREN-WAYNE-
INCLUDING THE CITIES OF...CENTERVILLE...CHARITON...CRESTON...
INDIANOLA...KNOXVILLE...LAMONI...OSKALOOSA AND PELLA
334 PM CDT SUN OCT 21 2001

THREAT                         PROBABILITY      EVENT TIMING
------                         -----------      ------------
THUNDERSTORMS
  TORNADO                         NONE.
  DAMAGING WINDS (58+ MPH)        LOW.         9 AM MON - 12 AM TUE.
  LARGE HAIL (3/4+)              LOW.         3 PM SUN -  7 PM SUN
                                                        AND
                                               3 AM MON - 12 AM TUE.
  FLASH FLOODING                  NONE.

* SPOTTER ACTIVATION OUTLOOK      LOW.         3 PM SUN -  7 PM SUN
                                                        AND
                                               3 AM MON - 12 AM TUE.

MS OCT 01
-------------------------------------------------------------------

FOR MORE INFORMATION INCLUDING THE THREAT DEFINITIONS...PROBABILITY
CATEGORIES...AND STORM PREDICTION CENTER OUTLOOKS...SEE THE
DES MOINES NATIONAL WEATHER SERVICE WEBSITE AT
HTTP://WWW.CRH.NOAA.GOV/DMX/HWO.HTML (IN ALL LOWER CASE).

Special weather statement, Oct 21, 3:34 PM CDT, 38 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
334 PM CDT SUN OCT 21 2001

.A WARM FRONT OVER NORTHERN MISSOURI WILL BEGIN TO LIFT NORTH
TONIGHT.  RELATIVELY WARM MOIST AIR MOVING NORTH INTO IOWA TONIGHT
AND MONDAY WILL CAUSE SCATTERED THUNDERSTORMS TO DEVELOP. THE
GREATEST THREAT FROM THESE STORMS WILL BE HAIL WITH A SECONDARY WIND
THREAT DURING THE DAY AND EVENING MONDAY.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070-071-221100-
ADAIR-AUDUBON-BLACK
HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CASS-CERRO
GORDO-CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-
HANCOCK-HARDIN-HUMBOLDT-JASPER-KOSSUTH-MARSHALL-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-SAC-STORY-TAMA-WEBSTER-WINNEBAGO-
WORTH-WRIGHT-
INCLUDING THE CITIES OF...ALGONA...AMES...ATLANTIC...BOONE...
CARROLL...DENISON...DES MOINES...ESTHERVILLE...FORT DODGE...
GRINNELL...IOWA FALLS...MARSHALLTOWN...MASON CITY...NEWTON...PERRY...
WATERLOO...WAVERLY AND WEBSTER CITY
334 PM CDT SUN OCT 21 2001

THREAT                         PROBABILITY      EVENT TIMING
------                         -----------      ------------

THUNDERSTORMS
  TORNADO                         NONE.
  DAMAGING WINDS (58+ MPH)        LOW.         9 AM MON - 12 AM TUE.
  LARGE HAIL (3/4+)              LOW.         5 AM MON - 12 AM TUE.
  FLASH FLOODING                  NONE.

* SPOTTER ACTIVATION OUTLOOK      LOW.         6 AM MON - 12 AM TUE.

* THE THREAT OF THUNDERSTORMS WILL BE GREATEST OVER SOUTHERN IOWA
MONDAY MORNING AND THEN SPREAD NORTH INTO NORTHERN IOWA MONDAY
AFTERNOON AND EVENING.

IAZ072>075-081>085-092>096-221100-
ADAMS-APPANOOSE-CLARKE-DECATUR-LUCAS-MADISON-MAHASKA-MARION-MONROE-
RINGGOLD-TAYLOR-UNION-WARREN-WAYNE-
INCLUDING THE CITIES OF...CENTERVILLE...CHARITON...CRESTON...
INDIANOLA...KNOXVILLE...LAMONI...OSKALOOSA AND PELLA
334 PM CDT SUN OCT 21 2001

THREAT                         PROBABILITY      EVENT TIMING
------                         -----------      ------------
THUNDERSTORMS
  TORNADO                         NONE.
  DAMAGING WINDS (58+ MPH)        LOW.         9 AM MON - 12 AM TUE.
  LARGE HAIL (3/4+)              LOW.         3 PM SUN -  7 PM SUN
                                                        AND
                                               3 AM MON - 12 AM TUE.
  FLASH FLOODING                  NONE.

* SPOTTER ACTIVATION OUTLOOK      LOW.         3 PM SUN -  7 PM SUN
                                                        AND
                                               3 AM MON - 12 AM TUE.

MS OCT 01
-------------------------------------------------------------------

FOR MORE INFORMATION INCLUDING THE THREAT DEFINITIONS...PROBABILITY
CATEGORIES...AND STORM PREDICTION CENTER OUTLOOKS...SEE THE
DES MOINES NATIONAL WEATHER SERVICE WEBSITE AT
HTTP://WWW.CRH.NOAA.GOV/DMX/HWO.HTML (IN ALL LOWER CASE).

Local storm report, Oct 21, 3:58 PM CDT, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
358 PM CDT SUN OCT 21 2001

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0309 PM    NEW MARKET                IA   1 INCH HAIL
10/21/01   TAYLOR                         REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

0348 PM    4 SW CONWAY               IA   .75 INCH HAIL
10/21/01   TAYLOR                         REPORTED BY STORM
                                          SPOTTER.

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 21, 2:55 PM CDT	Severe Thunderstorm Warning	DMX	Taylor	35 min
Oct 21, 3:42 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold, Taylor	48 min
Oct 21, 4:33 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold	42 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2001 Every severe thunderstorm warning in 2001

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.