Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 541

April 14, 201234 counties in Iowa; Putnam County, Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2012, 11:28 PM CDT for 34 counties in Iowa; Putnam County, Missouri. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Apr 14, 2012, 11:28 PM CDT (04:28 UTC)
Expired
Apr 15, 2012, 1:00 AM CDT
In force
92 min
Issued by
the Storm Prediction Center
All 35 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Iowa County, IA, Jasper County, IA, Keokuk County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Putnam County, MO

The radar

The Des Moines radar (KDMX), 27 km from the middle of the area, began a volume at 04:28 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 00:00Z, 4.5 hours before the alert went out and 208 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 00:00Z on 2012-04-15Temperature 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 00:00Z on 2012-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 276 square meters per square second.1939587897Sfc1 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
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.

624 
ACUS11 KWNS 150428
SWOMCD
SPC MCD 150428 
IAZ000-MOZ000-150600-

MESOSCALE DISCUSSION 0541
NWS STORM PREDICTION CENTER NORMAN OK
1128 PM CDT SAT APR 14 2012

AREAS AFFECTED...CENTRAL IOWA

CONCERNING...TORNADO WATCH 169...

VALID 150428Z - 150600Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 169 CONTINUES.

HOWEVER...IN THE NEAR TERM IT APPEARS TO BE DECREASING...AND A NEW
WW IS NOT ANTICIPATED PRIOR TO THE 05Z EXPIRATION OF WW 169.

AS THE DEEP SURFACE CYCLONE CONTINUES TO MIGRATE OUT OF NORTHWEST
KANSAS INTO EAST CENTRAL NEBRASKA THROUGH 06-09Z...ITS MOIST AND
POTENTIALLY UNSTABLE WARM SECTOR MAY OVERSPREAD MUCH OF IOWA
OVERNIGHT.  AND IT IS NOT CERTAIN THAT AN ADDITIONAL WW WILL NOT BE
NEEDED LATER TONIGHT...ASSOCIATED WITH A SQUALL LINE STILL IN THE
PROCESS OF EVOLVING OVER THE CENTRAL/SOUTH CENTRAL PLAINS...WITHIN A
STRONG AND SHEARED DEEP LAYER MEAN FLOW...WHICH CONTINUES TO DEVELOP
NORTHEASTWARD.  HOWEVER...IT MAY STILL BE AT LEAST SEVERAL HOURS
AWAY BEFORE THIS BEGINS TO MATERIALIZE ACROSS CENTRAL IOWA.

..KERR.. 04/15/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DVN...DMX...EAX...FSD...OAX...

LAT...LON   42189571 42449388 42169245 41479178 40819216 40429315
            40829471 41209544 42189571

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 14, 7:50 PM CDTMesoscale DiscussionSPCBenton, Buchanan, Cedar, Delaware, Henry, Iowa and 13 more55 min
Apr 14, 7:51 PM CDTMesoscale DiscussionSPCCherokee, Ida, Lyon, Monona, O'Brien, Osceola and 3 more84 min
Apr 14, 8:41 PM CDTSevere Thunderstorm WatchSPCCedar, Clinton, Des Moines, Henry, Iowa, Jackson and 9 more4 hr
Apr 14, 9:54 PM CDTMesoscale DiscussionSPCCedar, Clinton, Jackson, Jones, Louisa, Muscatine and 1 more96 min
Apr 14, 10:09 PM CDTSevere Thunderstorm WatchSPCFremont, Harrison, Mills, Monona, Montgomery, Page and 3 more6 hr
Apr 15, 3:25 AM CDTMesoscale DiscussionSPCAdams, Audubon, Cass, Fremont, Harrison, Mills and 5 more95 min
Apr 15, 1:56 PM CDTMesoscale DiscussionSPCAudubon, Boone, Buena Vista, Butler, Calhoun, Carroll and 28 more94 min
Apr 15, 3:37 PM CDTTornado WatchSPCCerro Gordo, Chickasaw, Clay, Dickinson, Emmet, Floyd and 8 more7 hr
Apr 14, 11:48 PM CDTMesoscale DiscussionSPCClay, Platte87 min
Apr 15, 1:37 AM CDTTornado WatchSPCAndrew, Atchison, Buchanan, DeKalb, Gentry, Holt and 2 more5 hr
Apr 15, 4:32 AM CDTMesoscale DiscussionSPCBates, Buchanan, Caldwell, Cass, Clay, Clinton and 6 more88 min
Apr 15, 6:35 AM CDTMesoscale DiscussionSPCBarry, Barton, Dade, Jasper, Lawrence, McDonald and 1 more85 min
Apr 15, 6:38 AM CDTSevere Thunderstorm WatchSPCBarry, Jasper, Lawrence, McDonald, Newton4 hr
Apr 15, 9:25 AM CDTMesoscale DiscussionSPCBarry, Christian, Douglas, Greene, Howell, Laclede and 7 more95 min
Apr 15, 10:51 AM CDTTornado WatchSPCBarry, Camden, Christian, Crawford, Dallas, Dent and 19 more7 hr
Apr 15, 1:38 PM CDTMesoscale DiscussionSPCChristian, Crawford, Dent, Douglas, Howell, Laclede and 9 more97 min
Apr 15, 4:22 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Carter, Crawford, Dent and 23 more83 min
Apr 15, 4:42 PM CDTTornado WatchSPCAudrain, Boone, Butler, Callaway, Carter, Cole and 35 more6 hr

Nearby

Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Missouri, 2012Every mesoscale discussion 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.