Alert archive / Nebraska / Mesoscale Discussions in 2009

Mesoscale Discussion 1839

August 9, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2009, 1:18 PM CDT for 4 states. It was in force for 27 min.

The area

The outline as issued.

The facts

Issued
Aug 9, 2009, 1:18 PM CDT (18:18 UTC)
Expired
Aug 9, 2009, 1:45 PM CDT
In force
27 min
Issued by
the Storm Prediction Center
All 37 counties

Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Taylor County, IA, Brown County, KS, Clay County, KS, Cloud County, KS, Doniphan County, KS, Jewell County, KS, Marshall County, KS, Mitchell County, KS, Nemaha County, KS, Ottawa County, KS, Pottawatomie County, KS, Republic County, KS, Riley County, KS, Washington County, KS, Atchison County, MO, Holt County, MO, Nodaway County, MO, Cass County, NE, Clay County, NE, Fillmore County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Seward County, NE, Thayer County, NE

The radar

The Omaha radar (KOAX), 104 km from the middle of the area, began a volume at 18:20 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, 6.3 hours before the alert went out and 104 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 2009-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1138 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 2009-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 square meters per square second.19395878Sfc1 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
1138 J/kg
Mixed-layer CIN
-213 J/kg
Mixed-layer LCL
726 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.9

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 5:01 AM CDTMesoscale DiscussionSPCHarrison, Monona, Pottawattamie59 min
Aug 9, 5:16 AM CDTSevere Thunderstorm WatchSPCHarrison, Monona, Pottawattamie, Shelby6 hr
Aug 9, 6:30 AM CDTMesoscale DiscussionSPCAudubon, Black Hawk, Boone, Bremer, Butler, Calhoun and 30 more2 hr
Aug 9, 6:54 AM CDTSevere Thunderstorm WatchSPCAdair, Audubon, Black Hawk, Boone, Bremer, Buena Vista and 36 more7 hr
Aug 9, 9:55 AM CDTMesoscale DiscussionSPCAdair, Adams, Allamakee, Audubon, Benton, Black Hawk and 68 more35 min
Aug 9, 10:21 AM CDTSevere Thunderstorm WatchSPCAllamakee, Benton, Buchanan, Cedar, Clayton, Clinton and 9 more8 hr
Aug 9, 11:16 AM CDTMesoscale DiscussionSPCHarrison, Pottawattamie, Shelby29 min
Aug 9, 1:40 PM CDTMesoscale DiscussionSPCAdair, Audubon, Black Hawk, Boone, Bremer, Butler and 23 more35 min
Aug 9, 3:44 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 32 more6 hr
Aug 9, 5:49 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Clarke, Davis, Decatur and 18 more86 min
Aug 9, 5:52 PM CDTSevere Thunderstorm WatchSPCBenton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more8 hr
Aug 8, 8:29 PM CDTSevere Thunderstorm WatchSPCBanner, Box Butte, Cheyenne, Dawes, Deuel, Garden and 5 more7 hr
Aug 8, 10:41 PM CDTMesoscale DiscussionSPCBanner, Box Butte, Cheyenne, Kimball, Morrill, Scotts Bluff and 1 more94 min

Nearby

Mesoscale Discussions in Nebraska, 2009Mesoscale Discussions in Kansas, 2009Mesoscale Discussions in Iowa, 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.