Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 1649

July 29, 20125 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2012, 11:03 PM CDT for 5 counties in Minnesota. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jul 29, 2012, 11:03 PM CDT (04:03 UTC)
Expired: Jul 30, 2012, 1:00 AM CDT
In force: 117 min
Issued by: the Storm Prediction Center

Counties Beltrami County, MN, Itasca County, MN, Koochiching County, MN, Lake County, MN, Saint Louis County, MN

The radar

The Duluth radar (KDLH), 166 km from the middle of the area, began a volume at 04:05 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

International Fa, MN (KINL), launched 00:00Z, 4.1 hours before the alert went out and 63 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: 1490 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 1732 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 119 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 4.9

Open this sounding in Storm Lab

The text

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

076 
ACUS11 KWNS 300403
SWOMCD
SPC MCD 300403 
MNZ000-300600-

MESOSCALE DISCUSSION 1649
NWS STORM PREDICTION CENTER NORMAN OK
1103 PM CDT SUN JUL 29 2012

AREAS AFFECTED...NRN MN

CONCERNING...SEVERE THUNDERSTORM WATCH 539...

VALID 300403Z - 300600Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 539
CONTINUES.

SUMMARY...PRIMARY SEVERE THREAT INCLUDING ISOLATED DAMAGING WIND
GUSTS AND HAIL EXPECTED TO PERSIST FROM NWRN THROUGH NCNTRL MN NEXT
COUPLE OF HOURS.

DISCUSSION...STORMS HAVE EVOLVED INTO A DOMINANT LINEAR STRUCTURE
ALONG OUTFLOW BOUNDARY AND FRONT MERGER OVER NWRN MN...WHILE
CELLULAR ACTIVITY IS INCREASING FARTHER SOUTHEAST WITHIN ZONE OF
ISENTROPIC ASCENT RELATED TO STRENGTHENING SWLY LLJ. GREATEST THREAT
FOR ISOLATED DAMAGING WIND EXISTS WITH LINE OF STORMS OVER NWRN MN
AS WELL AS WITH SMALL BOWING LINE SEGMENT MOVING THROUGH POLK
COUNTRY. THE ACTIVITY DEVELOPING WITHIN WARM ADVECTION REGIME ARE
MOST LIKELY ELEVATED...BUT SOME OF THIS ACTIVITY MIGHT BECOME
CAPABLE OF PRODUCING AT LEAST MARGINALLY SEVERE HAIL. 

OTHER STORMS OVER SRN ONTARIO MAY CROSS INTO NCNTRL MN AND POSE A
THREAT FOR STRONG TO DAMAGING WIND GUSTS AND HAIL. SEVERE THREAT IS
MORE MARGINAL WITH ERN EXTENT TOWARD THE ARROWHEAD WHERE SFC LAYER
HAS BEEN STABILIZED BY A LARGE CONVECTIVE OUTFLOW BOUNDARY.

..DIAL.. 07/30/2012

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

ATTN...WFO...DLH...FGF...

LAT...LON   48639506 48449319 48169162 47389115 47009268 47939610
            48639506

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 29, 7:37 PM CDT	Mesoscale Discussion	SPC	Kittson, Koochiching, Lake of the Woods, Marshall, Roseau	53 min
Jul 29, 7:51 PM CDT	Severe Thunderstorm Watch	SPC	Beltrami, Itasca, Kittson, Koochiching, Lake, Lake of the Woods and 3 more	6 hr

Nearby

Mesoscale Discussions in Minnesota, 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.