Alert archive / Iowa / Mesoscale Discussions in 2014

Mesoscale Discussion 1749

September 20, 201411 counties in Iowa; 10 counties in Minnesota; 11 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 20, 2014, 7:25 PM CDT for 11 counties in Iowa; 10 counties in Minnesota; 11 counties in Wisconsin. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
Sep 20, 2014, 7:25 PM CDT (00:25 UTC)
Expired
Sep 20, 2014, 8:30 PM CDT
In force
65 min
Issued by
the Storm Prediction Center
All 32 counties

Allamakee County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Floyd County, IA, Hancock County, IA, Howard County, IA, Kossuth County, IA, Mitchell County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Wabasha County, MN, Winona County, MN, Buffalo County, WI, Clark County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Trempealeau County, WI, Vernon County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 116 km from the middle of the area, began a volume at 00:29 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

Minneapolis, MN (KMPX), launched 00:00Z, 0.4 hours before the alert went out and 158 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, Minneapolis, MN at 00:00Z on 2014-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2014-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -105 square meters per square second.1939587897117136Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
906 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
-105 m²/s²
0-3 km storm-relative helicity
-127 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.

195 
ACUS11 KWNS 210026
SWOMCD
SPC MCD 210025 
WIZ000-IAZ000-MNZ000-210130-

MESOSCALE DISCUSSION 1749
NWS STORM PREDICTION CENTER NORMAN OK
0725 PM CDT SAT SEP 20 2014

AREAS AFFECTED...SERN MN...NERN IA...SWRN WI

CONCERNING...SEVERE THUNDERSTORM WATCH 506...

VALID 210025Z - 210130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 506
CONTINUES.

SUMMARY...SEVERE THREAT IS SHIFTING SOUTHEAST ACROSS WW506.

DISCUSSION...EXIT REGION OF STRONG MID-LEVEL SPEED MAX IS
TRANSLATING SEWD ACROSS THE UPPER MS VALLEY TOWARD THE UPPER GREAT
LAKES.  STRONGEST CONVECTION REMAINS FOCUSED IMMEDIATELY AHEAD OF
DIGGING VORT WHERE A LONG-LIVED SUPERCELL IS NOW MOVING INTO NRN
HOWARD COUNTY IA. THIS ACTIVITY IS MOVING QUICKLY SEWD AT ROUGHLY
40-45KT AND SHOULD TRACK ACROSS EXTREME NERN IA BEFORE MOVING INTO
SWRN WI...MOST LIKELY NEAR CRAWFORD COUNTY.  HAIL AND GUSTY WINDS
ARE EXPECTED WITH THIS FAST-MOVING CONVECTION.

..DARROW.. 09/21/2014

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

ATTN...WFO...GRB...ARX...MPX...DMX...

LAT...LON   42889458 44749288 44748961 42879138 42889458

Nearby

Mesoscale Discussions in Iowa, 2014Mesoscale Discussions in Wisconsin, 2014Mesoscale Discussions in Minnesota, 2014Every mesoscale discussion in 2014

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.