Alert archive / Nebraska / Mesoscale Discussions in 2009

Mesoscale Discussion 1925

August 19, 200920 counties in Iowa; 4 counties in Missouri; 34 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2009, 5:19 PM CDT for 20 counties in Iowa; 4 counties in Missouri; 34 counties in Nebraska. It was in force for 26 min.

The area

The outline as issued.

The facts

Issued
Aug 19, 2009, 5:19 PM CDT (22:19 UTC)
Expired
Aug 19, 2009, 5:45 PM CDT
In force
26 min
Issued by
the Storm Prediction Center
All 58 counties

Adams County, IA, Buena Vista County, IA, Cass County, IA, Cherokee County, IA, Crawford County, IA, Fremont County, IA, Harrison County, IA, Ida County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Page County, IA, Plymouth County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Taylor County, IA, Woodbury County, IA, Atchison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Hall County, NE, Hamilton County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Otoe County, NE, Platte County, NE, Polk County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE

The radar

The Omaha radar (KOAX), 7 km from the middle of the area, began a volume at 22:21 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.3 hours before the alert went out and 7 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 2009-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 285 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 2009-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 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
285 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
476 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

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

082 
ACUS11 KWNS 192220
SWOMCD
SPC MCD 192219 
IAZ000-MOZ000-NEZ000-SDZ000-192245-

MESOSCALE DISCUSSION 1925
NWS STORM PREDICTION CENTER NORMAN OK
0519 PM CDT WED AUG 19 2009

AREAS AFFECTED...ERN NEB / NWRN MO / WRN IA

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON 

VALID 192219Z - 192245Z

ENVIRONMENTAL CONDITIONS HAVE BECOME FAVORABLE FOR SEVERE STORMS AND
A WATCH ISSUANCE WILL BE COORDINATED BETWEEN THE SPC AND THE
AFFECTED LOCAL NATIONAL WEATHER SERVICE OFFICES SHORTLY.

RADAR MOSAIC IMAGERY SHOWS A BAND OF STRONG TO SEVERE STORMS
DEVELOPING ALONG A COLD FRONT FROM NWRN IA SWWD INTO CNTRL NEB WITH
ANOTHER CLUSTER DEVELOPING IN SERN NEB INTO NWRN MO/SWRN IA.

..SMITH.. 08/19/2009

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

ATTN...WFO...DMX...EAX...FSD...OAX...GID...

LAT...LON   40059467 40129570 40409838 40719883 41049861 41869776
            42819655 43349606 42989515 41509496 40529430 40059467

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 19, 11:51 AM CDTMesoscale DiscussionSPCCedar, Clinton, Des Moines, Henry, Lee, Louisa and 2 more114 min
Aug 19, 12:49 PM CDTTornado WatchSPCCedar, Clinton, Des Moines, Henry, Lee, Louisa and 2 more6 hr
Aug 19, 4:34 PM CDTMesoscale DiscussionSPCAllamakee, Clayton, Delaware, Dubuque, Jackson, Jones and 1 more56 min
Aug 19, 4:49 PM CDTTornado WatchSPCAllamakee, Buchanan, Cedar, Clayton, Clinton, Delaware and 10 more5 hr
Aug 19, 5:32 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 43 more6 hr
Aug 18, 8:41 PM CDTMesoscale DiscussionSPCDundy, Hitchcock, Red Willow64 min
Aug 18, 9:41 PM CDTMesoscale DiscussionSPCBlaine, Boyd, Brown, Custer, Holt, Hooker and 6 more64 min
Aug 19, 2:46 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Cedar, Clay and 26 more119 min

Nearby

Mesoscale Discussions in Nebraska, 2009Mesoscale Discussions in Iowa, 2009Mesoscale Discussions in Missouri, 2009Every mesoscale discussion in 2009

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.