Alert archive / Minnesota / Mesoscale Discussions in 2010

Mesoscale Discussion 1721

August 19, 201010 counties in Iowa; 16 counties in Minnesota; 5 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2010, 3:30 AM CDT for 10 counties in Iowa; 16 counties in Minnesota; 5 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 19, 2010, 3:30 AM CDT (08:30 UTC)
Expired
Aug 19, 2010, 5:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 31 counties

Allamakee County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Fayette County, IA, Floyd County, IA, Howard County, IA, Mitchell County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Blue Earth County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Le Sueur County, MN, Mower County, MN, Nicollet County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Winona County, MN, Buffalo County, WI, Crawford County, WI, La Crosse County, WI, Trempealeau County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 82 km from the middle of the area, began a volume at 08:30 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, 8.5 hours before the alert went out and 171 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 2010-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1423 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, Minneapolis, MN at 00:00Z on 2010-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 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
1423 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
807 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
140 m²/s²
0-3 km storm-relative helicity
330 m²/s²
Significant tornado parameter
1.3
Supercell composite
6.6

Open this sounding in Storm Lab

The text

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

481 
ACUS11 KWNS 190830
SWOMCD
SPC MCD 190830 
WIZ000-IAZ000-MNZ000-191030-

MESOSCALE DISCUSSION 1721
NWS STORM PREDICTION CENTER NORMAN OK
0330 AM CDT THU AUG 19 2010

AREAS AFFECTED...SRN MN...NRN IA...SWRN WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 190830Z - 191030Z

WATER VAPOR IMAGERY AND MODELS SUGGEST LIFT WITH AN UPPER FEATURE
EXTENDS FROM SRN WI WWD INTO SERN MN/NERN IA AS OF 08Z. ISENTROPIC
ASCENT ASSOCIATED WITH A SWLY LOW LEVEL JET HAS HELPED TO ENHANCE
LIFT IN THIS REGION...AND DESPITE MARGINAL ELEVATED
INSTABILITY...STEEP LAPSE RATES ALOFT ARE FAVORING DEVELOPMENT OF
ISOLATED STORMS.

EARLIER ACTIVITY OVER NWRN IA DISINTEGRATED AT IT MOVED SWD AWAY
FROM THE STRONGER INSTABILITY AND INTO A HIGHER CIN ENVIRONMENT.
MODELS SUGGEST THAT AFTER THE UPPER WAVE PASSES...HEIGHTS WILL RISE
COINCIDENT WITH WARMING ALOFT. THUS...A GENERAL DECREASE IN ACTIVITY
IS ANTICIPATED OVER MUCH OF SRN MN/IA. HOWEVER...GIVEN SUCH STEEP
LAPSE RATES AND FAVORABLE DEEP LAYER SHEAR...ISOLATED CORES MAY
PERSIST FROM SERN MN INTO NERN IA/FAR WRN WI WHERE IT IS COLDER
ALOFT WITH A MARGINAL HAIL THREAT.

..JEWELL.. 08/19/2010

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

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

LAT...LON   43059081 42809209 43159373 43659454 44269459 44639398
            44519175 44169074 43869058 43469056 43059081

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 10:41 PM CDTMesoscale DiscussionSPCAshland, Bayfield, Burnett, Douglas, Florence, Forest and 9 more2 hr

Nearby

Mesoscale Discussions in Minnesota, 2010Mesoscale Discussions in Iowa, 2010Mesoscale Discussions in Wisconsin, 2010Every mesoscale discussion in 2010

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.