Alert archive / Iowa / Tornado Warnings in 2012

Tornado Warning 7, NWS Omaha, NE

April 15, 2012Pottawattamie County, Iowa

NWS Omaha, NE issued this tornado warning at Apr 15, 2012, 12:57 AM CDT for Pottawattamie County, Iowa. It was in force for 15 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 15, 2012, 12:57 AM CDT (05:57 UTC)
Expired: Apr 15, 2012, 1:12 AM CDT
In force: 15 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon

County Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 77 km from the middle of the area, began a volume at 05:59 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
Apr 15, 1:05 AM CDT	TSTM WND DMG	5 Sw Mcclelland, IA	DAMAGE NEAR THE WESTFAIR AMPHITHEATRE...THEN EAST NORTHEAST FOR A MILE OR TWO.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 14, 10:09 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 6.0 hours before the alert went out and 77 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: 871 m above ground
0-6 km bulk shear: 73 kt
0-1 km storm-relative helicity: 276 m²/s²
0-3 km storm-relative helicity: 483 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

522 
WFUS53 KOAX 150557
TOROAX

IAC155-150630-
/O.NEW.KOAX.TO.W.0007.120415T0557Z-120415T0630Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1257 AM CDT SUN APR 15 2012

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  POTTAWATTAMIE COUNTY IN SOUTHWESTERN IOWA...

* UNTIL 130 AM CDT

* AT 1255 AM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 
  CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 
  NEAR UNDERWOOD...OR 14 MILES EAST OF OMAHA...AND MOVING NORTHEAST 
  AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  AVOCA...OAKLAND...WALNUT...HANCOCK AND MCCLELLAND. 

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 HIGHWAY 59 BETWEEN MILE MARKERS 52 AND 58.
 INTERSTATE 80 IN IOWA NEAR MILE MARKER 17...AND BETWEEN MILE 
MARKERS 40 AND 46.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO 
NOT WAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW.

&&

LAT...LON 4132 9527 4126 9575 4134 9580 4150 9538
      4150 9520
TIME...MOT...LOC 0555Z 245DEG 36KT 4130 9573 

$$

MAYES

3 follow-up statements

505 
WWUS53 KOAX 150603
SVSOAX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
103 AM CDT SUN APR 15 2012

IAC155-150630-
/O.CON.KOAX.TO.W.0007.000000T0000Z-120415T0630Z/
POTTAWATTAMIE IA-
103 AM CDT SUN APR 15 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 AM CDT FOR 
POTTAWATTAMIE COUNTY...

AT 1259 AM CDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO. THIS 
TORNADIC STORM WAS LOCATED NEAR UNDERWOOD...OR 17 MILES EAST OF 
OMAHA...MOVING NORTHEAST AT 40 MPH. 

LOCATIONS IMPACTED INCLUDE...
AVOCA...OAKLAND...WALNUT...UNDERWOOD...HANCOCK AND MCCLELLAND. 

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 HIGHWAY 59 BETWEEN MILE MARKERS 52 AND 58.
 INTERSTATE 80 IN IOWA NEAR MILE MARKER 17...AND BETWEEN MILE 
MARKERS 40 AND 46.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO 
NOT WAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW!

&&

LAT...LON 4132 9527 4126 9567 4127 9571 4136 9576
      4137 9574 4150 9538 4150 9520
TIME...MOT...LOC 0559Z 245DEG 36KT 4132 9568 

$$

MAYES

333 
WWUS53 KOAX 150608
SVSOAX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
108 AM CDT SUN APR 15 2012

IAC155-150630-
/O.CON.KOAX.TO.W.0007.000000T0000Z-120415T0630Z/
POTTAWATTAMIE IA-
108 AM CDT SUN APR 15 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 AM CDT FOR 
POTTAWATTAMIE COUNTY...

AT 104 AM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 
CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 
NEAR UNDERWOOD...OR 21 MILES EAST OF OMAHA...MOVING NORTHEAST AT 
40 MPH. 

LOCATIONS IMPACTED INCLUDE...
AVOCA...WALNUT AND HANCOCK. 

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 HIGHWAY 59 BETWEEN MILE MARKERS 52 AND 58.
 INTERSTATE 80 IN IOWA NEAR MILE MARKER 17...AND BETWEEN MILE 
MARKERS 40 AND 46.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO 
NOT WAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW!

&&

LAT...LON 4132 9527 4129 9567 4139 9568 4140 9566
      4150 9538 4150 9520
TIME...MOT...LOC 0604Z 245DEG 36KT 4134 9562 

$$

MAYES

137 
WWUS53 KOAX 150612
SVSOAX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
112 AM CDT SUN APR 15 2012

IAC155-150640-
/O.CAN.KOAX.TO.W.0007.000000T0000Z-120415T0630Z/
POTTAWATTAMIE IA-
112 AM CDT SUN APR 15 2012

...THE TORNADO WARNING FOR POTTAWATTAMIE COUNTY IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE 
LIMITS...AND NO LONGER APPEARS CAPABLE OF PRODUCING A TORNADO. 
THEREFORE THE WARNING HAS BEEN CANCELLED.  HOWEVER GUSTY WINDS AND 
HEAVY RAIN ARE STILL POSSIBLE WITH THIS THUNDERSTORM.

IN ADDITION...SEVERE THUNDERSTORM REDEVELOPMENT REMAINS POSSIBLE...
AND A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 2 AM. 

LAT...LON 4132 9527 4129 9567 4139 9568 4140 9566
      4150 9538 4150 9520
TIME...MOT...LOC 0612Z 245DEG 36KT 4134 9562 

$$

MAYES

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 14, 7:02 PM CDT	Areal Flood Advisory	OAX	Mills, Pottawattamie	58 min
Apr 14, 9:17 PM CDT	Wind Advisory	OAX	Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more	31 hr
Apr 14, 11:23 PM CDT	River Flood Warning	OAX	Page	16 hr
Apr 15, 12:09 AM CDT	Special Weather Statement	OAX	Fremont, Page	36 min
Apr 15, 12:41 AM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	34 min
Apr 15, 2:05 AM CDT	Special Weather Statement	OAX	Fremont, Page	85 min
Apr 15, 6:12 AM CDT	River Flood Warning	OAX	Fremont	16 hr

Nearby

Tornado Warnings in Iowa, 2012 Every tornado warning in 2012 Tornadoes in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.