Alert archive / Nebraska / Mesoscale Discussions in 2005

Mesoscale Discussion 839

May 12, 20054 states

The Storm Prediction Center issued this mesoscale discussion at May 12, 2005, 12:40 PM CDT for 4 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 12, 2005, 12:40 PM CDT (17:40 UTC)
Expired
May 12, 2005, 2:15 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 33 counties

Fremont County, IA, Page County, IA, Atchison County, KS, Brown County, KS, Doniphan County, KS, Jackson County, KS, Jefferson County, KS, Marshall County, KS, Nemaha County, KS, Pottawatomie County, KS, Shawnee County, KS, Andrew County, MO, Atchison County, MO, Buchanan County, MO, Holt County, MO, Nodaway County, MO, Butler County, NE, Cass County, NE, Colfax County, NE, Gage County, NE, Johnson County, NE, Lancaster County, NE, Nance County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Polk County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE

The radar

The Topeka radar (KTWX), 129 km from the middle of the area, began a volume at 17:42 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

Topeka, KS (KTOP), launched 12:00Z, 5.7 hours before the alert went out and 131 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, Topeka, KS at 12:00Z on 2005-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 47 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, Topeka, KS at 12:00Z on 2005-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 418 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
47 J/kg
Mixed-layer CIN
-239 J/kg
Mixed-layer LCL
1153 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
418 m²/s²
0-3 km storm-relative helicity
395 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 
ACUS11 KWNS 121741
SWOMCD
SPC MCD 121740 
IAZ000-MOZ000-KSZ000-NEZ000-121915-

MESOSCALE DISCUSSION 0839
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM CDT THU MAY 12 2005

AREAS AFFECTED...PORTIONS SERN NEB...NERN KS...NWRN MO...SWRN IA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 121740Z - 121915Z

SEVERE TSTMS -- INCLUDING POTENTIAL FOR A FEW SUPERCELLS -- ARE
POSSIBLE OVER MO VALLEY REGION FROM SERN NEB/SWRN IA ACROSS NERN
KS/NWRN MO THROUGH AFTERNOON.  WW MAY BE REQUIRED.

17Z SFC MESOANALYSIS AND VIS IMAGERY INDICATE OUTFLOW BOUNDARY FROM
EARLIER CONVECTION EXTENDS FROM MKC AREA NWWD ACROSS NERN KS --
BETWEEN TOP-FNB -- TO NEAR BIE.  SYNOPTIC WARM FRONT IS DIFFUSE BUT
LOCATED ROUGHLY FROM NEAR STJ WNWWD TO NEAR LNK...THEN NWWD TO SFC
LOW S ONL.  COLD FRONT ARCS FROM LOW SWD BETWEEN CNK-MHK THEN SSWWD
NEAR HUT.  PREFRONTAL CONFLUENCE LINE EXTENDS FROM INTERSECTION WITH
OUTFLOW BOUNDARY -- NEAR BIE -- SWD TO MHK THEN SSWWD TO NEAR END. 
PRIND AREA MOST FAVORABLE FOR SFC-BASED TSTMS INITIALLY IS INVOF
OUTFLOW/CONFLUENCE INTERSECTION THEN SWD ALONG CONFLUENCE LINE AS
FRONT CATCHES UP.  CLEARING OF LOW CLOUDS WILL ALLOW AIR MASS
BETWEEN SYNOPTIC FRONT AND OUTFLOW BOUNDARY OVER SERN NEB TO
HEAT/DESTABILIZE NEXT FEW HOURS...CREATING ZONE OF SFC-BASED
BUOYANCY AND ENHANCED LOW LEVEL HODOGRAPHS THAT WILL SHIFT NEWD
ACROSS MO VALLEY TOWARD SWRN IA WITH TIME.  MESOLOW MAY DEVELOP
ALONG OUTFLOW BOUNDARY AS WELL...FURTHER ENHANCING LOW LEVEL SHEAR. 
0-1 KM SRH 100-200 J/KG IS POSSIBLE...WITH MLCAPES 1000-2000 J/KG
ALONG OUTFLOW BOUNDARY.

SEVERE POTENTIAL OVER NARROW PREFRONTAL CORRIDOR FROM LNK AREA NWWD
TOWARD SFC LOW IS QUITE CONDITIONAL BECAUSE OF BRIEF/LIMITED
OPPORTUNITY FOR SFC DESTABILIZATION PRIOR TO FROPA.  HEATING WITHIN
THIS CORRIDOR WILL BE LIMITED BY COMBINATION OF SLOW-ERODING LOW
STRATUS...AND HIGH CLOUDS OF ANVIL ORIGIN ADVECTING NEWD FROM
POSTFRONTAL/ELEVATED TSTMS OVER KS AND TX/OK PANHANDLES.

..EDWARDS.. 05/12/2005

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

ATTN...WFO...DMX...EAX...OAX...TOP...GID...

39759476 39349498 38759593 39149644 39779665 40919747
41519816 41919748 40689494 40079476

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 12, 3:44 AM CDTMesoscale DiscussionSPCFremont61 min
May 12, 1:55 PM CDTTornado WatchSPCFremont, Mills, Montgomery, Page, Pottawattamie7 hr
May 12, 3:48 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 27 more87 min
May 11, 8:01 PM CDTMesoscale DiscussionSPCCheyenne, Clark, Decatur, Finney, Ford, Gove and 24 more59 min
May 11, 9:26 PM CDTMesoscale DiscussionSPCDecatur, Ellis, Finney, Gove, Graham, Grant and 15 more64 min
May 11, 9:50 PM CDTTornado WatchSPCClark, Decatur, Edwards, Ellis, Finney, Ford and 28 more7 hr
May 11, 11:02 PM CDTMesoscale DiscussionSPCBrown, Marshall, Nemaha58 min
May 12, 1:16 PM CDTMesoscale DiscussionSPCBarber, Barton, Clark, Cloud, Comanche, Edwards and 21 more59 min
May 12, 1:35 PM CDTSevere Thunderstorm WatchSPCBarber, Barton, Clark, Clay, Cloud, Comanche and 29 more7 hr
May 12, 3:13 PM CDTMesoscale DiscussionSPCBarber, Barton, Clay, Cloud, Comanche, Dickinson and 28 more92 min
May 12, 5:18 PM CDTMesoscale DiscussionSPCBarber, Butler, Cowley, Harper, Harvey, Kingman and 2 more57 min
May 12, 5:55 PM CDTSevere Thunderstorm WatchSPCBarber, Butler, Chase, Coffey, Comanche, Cowley and 14 more7 hr
May 12, 6:37 PM CDTMesoscale DiscussionSPCCaldwell, Carroll, Chariton, Clay, Clinton, Cooper and 13 more83 min
May 12, 6:55 PM CDTSevere Thunderstorm WatchSPCAdair, Audrain, Boone, Caldwell, Callaway, Carroll and 32 more6 hr
May 11, 7:02 PM CDTMesoscale DiscussionSPCAdams, Arthur, Boone, Buffalo, Butler, Chase and 33 more88 min
May 11, 11:50 PM CDTSevere Thunderstorm WatchSPCAdams, Boone, Buffalo, Butler, Cass, Clay and 30 more5 hr

Nearby

Mesoscale Discussions in Nebraska, 2005Mesoscale Discussions in Kansas, 2005Mesoscale Discussions in Missouri, 2005Every mesoscale discussion 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.