Alert archive / Missouri / Mesoscale Discussions in 2011

Mesoscale Discussion 253

March 22, 2011Hancock County, Henderson County, Warren County, Illinois; Des Moines County, Lee County, Iowa; 4 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Mar 22, 2011, 11:21 PM CDT for Hancock County, Henderson County, Warren County, Illinois; Des Moines County, Lee County, Iowa; 4 counties in Missouri. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Mar 22, 2011, 11:21 PM CDT (04:21 UTC)
Expired: Mar 23, 2011, 12:45 AM CDT
In force: 84 min
Issued by: the Storm Prediction Center

Counties Des Moines County, IA, Lee County, IA, Hancock County, IL, Henderson County, IL, Warren County, IL, Adair County, MO, Clark County, MO, Linn County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 196 km from the middle of the area, began a volume at 04:23 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, 4.4 hours before the alert went out and 201 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: 8 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 418 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 787 m²/s²
0-3 km storm-relative helicity: 972 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

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

789 
ACUS11 KWNS 230422
SWOMCD
SPC MCD 230421
ILZ000-IAZ000-MOZ000-230545-

MESOSCALE DISCUSSION 0253
NWS STORM PREDICTION CENTER NORMAN OK
1121 PM CDT TUE MAR 22 2011

AREAS AFFECTED...SERN IA...NERN MO AND W CNTRL IL

CONCERNING...TORNADO WATCH 54...

VALID 230421Z - 230545Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 54 CONTINUES.

THREAT FOR ISOLATED DAMAGING WIND AND PERHAPS A TORNADO WILL PERSIST
ANOTHER COUPLE HOURS FROM NERN MO THROUGH SERN IA INTO W CNTRL IL.
STORMS ARE APPROACHING THE EDGE OF WW 54 IN SERN IA.
HOWEVER...THREAT DOES NOT APPEAR SUFFICIENT TO WARRANT ANOTHER WW AT
THIS TIME.

FORCED LINE OF STORMS EXTENDS FROM ERN IA SWWD INTO NRN MO MOVING
EAST AT 35 KT. ACTIVITY HAS BEEN BACKBUILDING ALONG COLD FRONT INTO
NRN MO RESULTING IN SOMEWHAT SLOWER NET MOTION ALONG THAT PORTION OF
LINE. STORMS OVER SERN IA ARE APPROACHING ERN EDGE OF WW 54. THREAT
FOR MAINLY ISOLATED DAMAGING WIND MAY PERSIST INTO W-CNTRL IL...BUT
INSTABILITY DECREASES AND BOUNDARY LAYER IS MORE STABLE WITH ERN
EXTENT INTO IL WHICH SHOULD SERVE AS A LIMITING FACTOR. RECENT RADAR
TRENDS SHOW OUTFLOW BEGINNING TO ACCELERATE AHEAD OF THE UPDRAFT
CORES...SUGGESTING THE START OF A POSSIBLE WEAKENING TREND.

FARTHER SW INTO NRN MO...STORMS CONTINUE TO TRAIN NEWD ALONG THE
COLD FRONT. ACTIVITY WILL REMAIN IN THE MORE UNSTABLE PORTION OF
WARM SECTOR LONGER...AND VERTICAL SHEAR REMAINS SUPPORTIVE OF
OCCASIONAL BOWING SEGMENTS AND EMBEDDED SUPERCELLS. THREAT FOR
ISOLATED DAMAGING WIND AND PERHAPS A TORNADO WILL PERSIST WITH THIS
ACTIVITY NEXT COUPLE HOURS.

..DIAL.. 03/23/2011

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

ATTN...WFO...LSX...DVN...DMX...EAX...

LAT...LON   40129321 40609219 41179101 40819057 40299098 40279210
            39769271 39709345 40129321

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 23, 3:20 PM CDT	Mesoscale Discussion	SPC	Iroquois, Vermilion	85 min
Mar 22, 8:00 PM CDT	Mesoscale Discussion	SPC	Appanoose, Davis, Des Moines, Henry, Jefferson, Keokuk and 7 more	60 min
Mar 22, 8:35 PM CDT	Tornado Watch	SPC	Appanoose, Davis, Henry, Jefferson, Keokuk, Lucas and 7 more	5 hr

Nearby

Mesoscale Discussions in Missouri, 2011 Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Iowa, 2011 Every mesoscale discussion in 2011

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.