Alert archive / Iowa / Tornado Watches in 2005

Tornado Watch 878

November 27, 200524 counties in Iowa

The Storm Prediction Center issued this tornado watch at Nov 27, 2005, 5:38 PM CST for 24 counties in Iowa. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Nov 27, 2005, 5:38 PM CST (23:38 UTC)
Expired
Nov 27, 2005, 8:51 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
All 24 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Guthrie County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 63 km from the middle of the area, began a volume at 23:41 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.

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Nov 27, 5:39 PM CSTSevere Thunderstorm WarningDMXLucas16 min
Nov 27, 5:44 PM CSTSevere Thunderstorm WarningDMXWarren36 min
Nov 27, 6:11 PM CSTSevere Thunderstorm WarningDMXMarion17 min
Nov 27, 6:14 PM CSTSevere Thunderstorm WarningDMXJasper, Polk46 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.6 hours before the alert went out and 191 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 2005-11-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2005-11-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 146 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
623 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
146 m²/s²
0-3 km storm-relative helicity
113 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 
WWUS20 KWNS 272335
SEL8  
SPC WW 272335
IAZ000-280600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 878
NWS STORM PREDICTION CENTER NORMAN OK
535 PM CST SUN NOV 27 2005

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTH CENTRAL IOWA

EFFECTIVE THIS SUNDAY AFTERNOON FROM 535 PM UNTIL MIDNIGHT CST.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 75 MILES WEST NORTHWEST OF LAMONI
IOWA TO 10 MILES NORTHEAST OF OTTUMWA IOWA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 875...WW 876...WW 877...

DISCUSSION...SCATTERED STRONG/SEVERE THUNDERSTORMS WILL MOVE FROM
NORTHERN MO INTO SOUTH CENTRAL IA DURING THE EVENING HOURS.  DESPITE
COOL SURFACE AIRMASS...SUFFICIENT INSTABILITY ALOFT AND RAPID LOW
LEVEL DESTABILIZATION PRESENTS SOME THREAT OF SURFACE-BASED STORMS. 
VERY STRONG WIND FIELDS WILL PROMOTE SUPERCELL STORMS AND THE
POTENTIAL FOR DAMAGING WINDS AND BRIEF TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 22040.


...HART

414,0951 415,0921 403,0921 402,0951

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 27, 3:29 PM CSTMesoscale DiscussionSPCAdair, Adams, Cass, Clarke, Decatur, Fremont and 10 more2 hr
Nov 27, 12:36 PM CSTTornado WatchSPCBarton, Jasper, McDonald, Newton, Vernon7 hr
Nov 27, 2:50 PM CSTMesoscale DiscussionSPCAndrew, Barry, Barton, Bates, Benton, Boone and 50 more115 min
Nov 27, 3:05 PM CSTTornado WatchSPCAdair, Andrew, Atchison, Barry, Bates, Benton and 65 more7 hr
Nov 27, 4:39 PM CSTMesoscale DiscussionSPCButler, Carter, Dunklin, New Madrid, Pemiscot, Ripley and 2 more96 min
Nov 27, 5:58 PM CSTMesoscale DiscussionSPCAndrew, Barry, Bates, Benton, Boone, Buchanan and 52 more92 min

Nearby

Tornado Watches in Iowa, 2005Every tornado watch in 2005

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.