Alert archive / Iowa / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 404, NWS Des Moines, IA

July 17, 2008Humboldt County, Pocahontas County, Webster County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 17, 2008, 2:37 PM CDT for Humboldt County, Pocahontas County, Webster County, Iowa. It was in force for 38 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
Jul 17, 2008, 2:37 PM CDT (19:37 UTC)
Expired
Jul 17, 2008, 3:15 PM CDT
In force
38 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon

Counties Humboldt County, IA, Pocahontas County, IA, Webster County, IA

The radar

The Des Moines radar (KDMX), 120 km from the middle of the area, began a volume at 19:39 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 17, 10:57 AM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.6 hours before the alert went out and 230 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-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2008-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1745 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2008-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1745 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
925 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
49 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 171936
SVRDMX
IAC091-151-187-172015-
/O.NEW.KDMX.SV.W.0404.080717T1937Z-080717T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
237 PM CDT THU JUL 17 2008

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN WEBSTER COUNTY IN CENTRAL IOWA...
  SOUTHWESTERN HUMBOLDT COUNTY IN NORTH CENTRAL IOWA...
  SOUTHEASTERN POCAHONTAS COUNTY IN NORTHWEST IOWA...

* UNTIL 315 PM CDT.

* AT 234 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  GILMORE CITY...OR 21 MILES NORTHWEST OF FORT DODGE...AND MOVING
  EAST AT 29 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  GILMORE CITY BY 240 PM CDT...
  PIONEER AND 8 MILES SOUTH OF BRADGATE BY 245 PM CDT...
  CLARE BY 250 PM CDT...
  RUTLAND BY 255 PM CDT...
  DAKOTA CITY AND HUMBOLDT BY 305 PM CDT...
  BADGER BY 310 PM CDT...

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU LIVE IN A
MOBILE HOME...SEEK SHELTER IN A STURDY BUILDING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 600 PM CDT
THURSDAY EVENING FOR NORTHWESTERN IOWA.

REPORT TORNADOES...WIND IN EXCESS OF 50 MPH...HAIL LARGER THAN ONE
HALF INCH...OR STORM DAMAGE BY CALLING LOCAL LAW ENFORCEMENT AND
ASKING THEM TO RELAY THE REPORT TO THE NATIONAL WEATHER SERVICE.

LAT...LON 4284 9412 4254 9411 4257 9461 4279 9460
TIME...MOT...LOC 1937Z 268DEG 25KT 4268 9448

$$

SMALL
1 follow-up statement
000 
WWUS53 KDMX 172013
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
314 PM CDT THU JUL 17 2008

IAC091-151-187-172024-
/O.EXP.KDMX.SV.W.0404.000000T0000Z-080717T2015Z/
POCAHONTAS IA-WEBSTER IA-HUMBOLDT IA-
314 PM CDT THU JUL 17 2008

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN HUMBOLDT...
NORTHWESTERN WEBSTER AND SOUTHEASTERN POCAHONTAS COUNTIES WILL EXPIRE
AT 315 PM CDT...

AT 311 PM CDT...WEATHER SERVICE DOPPLER RADAR INDICATED THAT THE
THUNDERSTORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE AREA.
THEREFORE...THE SEVERE THUNDERSTORM WARNING HAS BEEN ALLOWED TO
EXPIRE.

REPORT TORNADOES...WIND IN EXCESS OF 50 MPH...HAIL LARGER THAN ONE
HALF INCH...OR STORM DAMAGE BY CALLING LOCAL LAW ENFORCEMENT AND
ASKING THEM TO RELAY THE REPORT TO THE NATIONAL WEATHER SERVICE.

LAT...LON 4284 9412 4254 9411 4257 9461 4279 9460
TIME...MOT...LOC 2014Z 268DEG 25KT 4269 9413

$$

SMALL

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 Jul 17, 12:53 PM CDT, 1 hour 44 minutes earlier.

Area forecast discussion, Jul 17, 12:53 PM CDT, 1 hour 44 minutes before
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1248  AM CDT THU JUL 17 2008

.UPDATED FOR 18Z AVIATION DISCUSSION.

.DISCUSSION...
TSRA CLUSTERS CONTINUE TO SKIRT TO THE N THE CWA WITH NEXT ROUND
COMING ACRS SD AND NEBRASKA ATTM LEADING TO CONCERN FOR TEMPS TDA.
A BIT GUNSHY AFT THE COOL POOL HELD TEMPS DOWN YDA.  FEEL ENUF
DEBRIS WILL AFFECT THE N TO KEEP TEMPS IN THE LOW 80S.  WHILE ON
TEMPS...ADJ TEMPS DNWD FOR FRI WITH CLOUDS AND PCPN AND DONT FEEL
IT WILL GET OUT OF THE 70S IN THE N WITH ONLY THE FAR S AND SE WRMG
UP TO THE UPR 80S.  PCPN IS MORE PROBLEMATIC TDA.  COMPLICATED STTN
WITH THE SERIES OF S/WVS MOVING THROUGH THE WRLY FLOW.  WENT WITH
DVLPMT LATE IN THE DAY OVR THE FAR N.  FEEL IT WILL BE A SLOW
PROCESS TO GET THE PCPN TO MOVE SWD.  PUT IN MNTN OF SVR AND LCLY R+
IN MY LKLY AREA OF THE NW THIS EVE.  HISTORY OF THIS AMS...GIVEN THE
DECENT CAPE AND LOW SHEAR...IS FOR ANY SVR WX TO OCCUR BFR 05Z FOR
THE MOST PART.  WILL PLAY IT THAT WAY AGN TNGT. SVR POT FOR FRI
LOOKING LESS LKLY THAN TDA WITH STTN GOING MORE TWD HVR RAFL INSTEAD
OF SVR.  SWODY2 COVERS DISCUSSION OF THIS WELL.  LTL CHNG ELSW IN
THE FCST...BUT WILL NEED TO LOOK A BIT CLOSER AT THE MON TUE
TIMEFRAME TDA AS IT APPEARS SYS MOVING A BIT QUICKER.

.HYDROLOGY...
NO HEADLINES THIS PKG AS CONFIDENCE IS LOW ON WHERE AND HOW MUCH
PCPN WE WILL GET.  MDLS KEEP MOST OF IT IN NEBRASKA...BUT HAVE
QUESTIONS WITH THAT.  FEELING IS THAT MUCH OF THE STATE WILL BE IN
THE 1.5 TO 2 INCH RANGE...BUT OVER A 60 TO 72 HOUR TIME PERIOD.
GIVEN THERE HASNT BEEN ALL THAT MUCH RAIN IN A WHILE...THAT SHOULD
BE ABLE TO BE HANDLED EASILY EVEN IF WE DO GET SPOT 3-4 INCH AMTS.

&&

.AVIATION...17/18Z
A COUPLE OF DIFFERENT ROUNDS ARE POSSIBLE BEFORE 18Z
FRIDAY...ESPECIALLY FOR KFOD AND KMCW...BUT DIFFICULT TO PINPOINT
EXACT TIMING AND LOCATION DUE TO RELATIVELY WEAK FORCING. STORMS
WILL PRODUCE GUSTY WINDS AND TORRENTIAL DOWNPOURS...WHICH WILL TAKE
CONDITIONS TO IFR FOR AWHILE AS THEY MOVE THROUGH. AFTER
06Z...WEATHER SHOULD CALM DOWN IN THE NORTH...AND FOCUS MORE IN
CENTRAL IA...WITH ANOTHER ROUND OF ACTIVE STORMS EXPECTED ON FRIDAY.

&&

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

&&

LONG TERM...MS JUL 08
SHORT TERM...REV
AVIATION...KJ
Hazardous weather outlook, Jul 17, 11:36 AM CDT, 3 hours 1 minute before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1136 AM CDT THU JUL 17 2008

IAZ004>007-015>017-023>028-033>039-044>050-057>059-070-071-181645-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-
BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-CASS-ADAIR-
1136 AM CDT THU JUL 17 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THE THREAT FOR SEVERE WEATHER WILL BEGIN IN THE EARLY AFTERNOON
ALONG THE MINNESOTA BORDER...AS SCATTERED THUNDERSTORMS WORK THEIR
WAY SLOWLY SOUTH AND EAST. BY THIS EVENING...STORMS COULD REACH
FROM WEST CENTRAL AND CENTRAL IOWA INTO THE WATERLOO AREA...AND
POINTS NORTH. THE PRIMARY THREAT WILL BE FOR DAMAGING WINDS AND
LARGE HAIL. HEAVY RAINFALL IS POSSIBLE WITH GENERAL RAINFALL
TOTALS AROUND AN INCH...AND ISOLATED AMOUNTS OF 2 TO 3 INCHES
POSSIBLE TONIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE WILL BE A CHANCE FOR THUNDERSTORMS OFF AND ON FRIDAY THROUGH
NEXT TUESDAY. THERE IS A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS
BOTH FRIDAY AFTERNOON AND EVENING...AND TO A LESSER DEGREE LATE
SATURDAY AFTERNOON AND NIGHT. THE PRIMARY THREAT WILL BE DAMAGING
WINDS AND LARGE HAIL...WITH LOCALLY HEAVY RAINS POSSIBLE ON FRIDAY
AND FRIDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FROM AROUND 5 PM THROUGH MIDNIGHT
TONIGHT...AND AGAIN BOTH FRIDAY AND SATURDAY AFTERNOON AND EVENING.

IAZ060>062-072>075-081>086-092>097-181645-
POLK-JASPER-POWESHIEK-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-
CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-
APPANOOSE-DAVIS-
1136 AM CDT THU JUL 17 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL SPREAD SOUTHEAST ACROSS THE AREA
TONIGHT...MAINLY AFTER MIDNIGHT. SEVERE WEATHER IS NOT LIKELY WITH
THESE STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS WILL BE LIKELY FRIDAY AND FRIDAY NIGHT...THEN OFF
AND ON SATURDAY THROUGH NEXT TUESDAY. THERE IS A SLIGHT CHANCE
FOR SEVERE THUNDERSTORMS BOTH FRIDAY AFTERNOON AND EVENING...AND
TO A LESSER DEGREE LATE SATURDAY AFTERNOON AND NIGHT. THE PRIMARY
THREAT WILL BE DAMAGING WINDS AND LARGE HAIL. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE FRIDAY AFTERNOON AND NIGHT AS
WELL...WITH GENERAL RAINFALL AMOUNTS OF AROUND AN INCH AND ISOLATED
AMOUNTS OF UP TO 3 INCHES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED BOTH FRIDAY AND SATURDAY AFTERNOON
AND EVENING.

JUNGBLUTH

In the hours before

Local storm report, Jul 17, 2:26 PM CDT, 11 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
226 PM CDT THU JUL 17 2008

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

0222 PM     HAIL             SW MASON CITY           43.15N 93.20W
07/17/2008  E0.75 INCH       CERRO GORDO        IA   LAW ENFORCEMENT

            MM 183 ON AVENUE OF THE SAINTS. FROM IOWA STATE PATROL.

0225 PM     HAIL             SW MASON CITY           43.15N 93.20W
07/17/2008  E1.00 INCH       CERRO GORDO        IA   LAW ENFORCEMENT

            MM 183 AVENUE OF THE SAINTS. HAIL INCREASED TO QUARTER
            SIZED. FROM IOWA STATE PATROL

&&

KLP/BSS
Local storm report, Jul 17, 2:32 PM CDT, 5 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
232 PM CDT THU JUL 17 2008

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

0231 PM     HAIL             NNE MASON CITY          43.15N 93.20W
07/17/2008  E0.75 INCH       CERRO GORDO        IA   BROADCAST MEDIA

            REPORT AT KIMT

&&

KLP/BSS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 12:26 PM CDTSevere Thunderstorm WarningDMXEmmet, Palo Alto49 min
Jul 17, 12:52 PM CDTSevere Thunderstorm WarningDMXEmmet, Kossuth, Palo Alto38 min
Jul 17, 2:18 PM CDTSevere Thunderstorm WarningDMXHumboldt, Webster, Wright42 min
Jul 17, 2:21 PM CDTSevere Thunderstorm WarningDMXCerro Gordo39 min
Jul 17, 3:08 PM CDTSevere Thunderstorm WarningDMXFranklin, Hamilton, Hardin, Wright37 min
Jul 17, 3:12 PM CDTSevere Thunderstorm WarningDMXHamilton, Webster, Wright48 min
Jul 17, 5:45 PM CDTSevere Thunderstorm WarningDMXBoone45 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2008Every severe thunderstorm warning 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.