Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 388

March 29, 201212 counties in Iowa; 7 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Mar 29, 2012, 11:50 PM CDT for 12 counties in Iowa; 7 counties in Missouri. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Mar 29, 2012, 11:50 PM CDT (04:50 UTC)
Expired: Mar 30, 2012, 12:45 AM CDT
In force: 55 min
Issued by: the Storm Prediction Center

Counties Appanoose County, IA, Clarke County, IA, Decatur County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Ringgold County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Gentry County, MO, Grundy County, MO, Harrison County, MO, Mercer County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO

The radar

The Des Moines radar (KDMX), 122 km from the middle of the area, began a volume at 04:50 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

Davenport, (KDVN), launched 00:00Z, 4.8 hours before the alert went out and 253 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: 1518 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 199 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.

585 
ACUS11 KWNS 300450
SWOMCD
SPC MCD 300450 
IAZ000-MOZ000-300545-

MESOSCALE DISCUSSION 0388
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM CDT THU MAR 29 2012

AREAS AFFECTED...SOUTH CENTRAL IA AND NORTH CENTRAL MO

CONCERNING...SEVERE THUNDERSTORM WATCH 117...

VALID 300450Z - 300545Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 117
CONTINUES.

A FORWARD PROPAGATING MCS WILL CONTINUE TO MOVE EWD ACROSS SRN IA
AND NRN MO DURING THE OVERNIGHT PERIOD WITH AN ATTENDANT SEVERE
WEATHER THREAT PERSISTING THROUGH 06-07Z.  HOWEVER...RECENT RADAR
TRENDS WOULD SUGGEST THAT THE OVERALL SEVERE WEATHER THREAT MAY BE
BEGINNING TO DIMINISH.

TRENDS IN OBJECTIVE ANALYSES INDICATED MOST UNSTABLE CAPE HAS
CONTINUED TO DECREASE LATE THIS EVENING ACROSS SOUTH CENTRAL IA AND
NORTH CENTRAL MO WITH RECENT VALUES RANGING FROM 500-1000 J/KG. 
HOWEVER...THE PRESENCE OF STEEP MIDLEVEL LAPSE RATES /UP TO 7.5 C
PER KM/ AND EFFECTIVE BULK SHEAR OF 40-45 KT SUGGEST THE POTENTIAL
FOR ORGANIZED ELEVATED STORMS REMAINS AS THIS SYSTEM SHIFTS EWD.  

WATER VAPOR IMAGERY SHOWED THE SRN EXTENT OF A MID-UPPER LEVEL
TROUGH MOVING EWD THROUGH ERN NEB TO NWRN KS AT 0415Z.  FORCING FOR
ASCENT AHEAD OF THIS TROUGH AND LOW LEVEL WAA WITHIN THE NOSE OF A
SWLY 40-50 KT LLJ TRANSLATING EWD OVERNIGHT ARE EXPECTED TO MAINTAIN
THE MCS.  THE SWRN EXTENT OF THE MCS SHOULD REMAIN THE REGION TO
HAVE GREATEST SEVERE WEATHER THREAT...AS IT IS CLOSEST TO STRONGER
INSTABILITY.

..PETERS.. 03/30/2012

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

ATTN...WFO...DMX...EAX...

LAT...LON   40049277 40139442 41059443 41519387 41499264 40899253
            40399265 40049277

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 29, 7:55 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Cass, Clarke, Dallas and 12 more	65 min
Mar 29, 8:30 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Cass, Clarke, Decatur and 9 more	6 hr
Mar 29, 9:51 PM CDT	Mesoscale Discussion	SPC	Fremont, Mills, Montgomery, Page	54 min
Mar 30, 3:20 PM CDT	Mesoscale Discussion	SPC	Adams, Audubon, Cass, Crawford, Fremont, Harrison and 7 more	85 min

Nearby

Mesoscale Discussions in Iowa, 2012 Mesoscale Discussions in Missouri, 2012 Every 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.