Alert archive / Minnesota / Mesoscale Discussions in 2005

Mesoscale Discussion 950

May 21, 200513 counties in Minnesota; 9 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at May 21, 2005, 1:24 PM CDT for 13 counties in Minnesota; 9 counties in North Dakota. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 21, 2005, 1:24 PM CDT (18:24 UTC)
Expired: May 21, 2005, 2:30 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center

All 22 counties

Becker County, MN, Clay County, MN, Clearwater County, MN, Kittson County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Otter Tail County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN, Wilkin County, MN, Cass County, ND, Grand Forks County, ND, Pembina County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Steele County, ND, Traill County, ND, Walsh County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 53 km from the middle of the area, began a volume at 18:25 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 310May 21, 3:15 PM CDT

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 6.4 hours before the alert went out and 289 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: 1002 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 39 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.

000 
ACUS11 KWNS 211825
SWOMCD
SPC MCD 211824 
MNZ000-NDZ000-211930-

MESOSCALE DISCUSSION 0950
NWS STORM PREDICTION CENTER NORMAN OK
0124 PM CDT SAT MAY 21 2005

AREAS AFFECTED...ERN ND INTO NWRN AND WEST CENTRAL MN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211824Z - 211930Z

WW BEING CONSIDERED FOR ERN ND INTO MUCH OF NWRN AND WEST CENTRAL MN
IN THE NEXT HOUR.

VIS IMAGERY INDICATED LINE OF CU DEVELOPING ALONG A COLD FRONT OVER
ERN ND /EAST OF A DVL-JMS LINE/ INTO ERN SD NEAR ABR TO WNW MHE. 
STRONGER FORCING WITH THE SHORT WAVE TROUGH IS CURRENTLY AIDING
THUNDERSTORM DEVELOPMENT ACROSS SERN SASKATCHEWAN/SWRN MANITOBA. 
DESPITE A CONTINUED INFLUX OF LOW LEVEL MOISTURE... ALBEIT A NARROW
AXIS ALONG/E FRONT...CLOUDINESS OVER ERN ND/NWRN MN WILL FURTHER
SLOW SURFACE BASED DESTABILIZATION.  MODIFIED RUC SOUNDINGS ALONG
THE ERN ND/MN BORDER SUGGEST MUCAPE VALUES NEAR 500 J/KG.

INCREASING LARGE SCALE ASCENT OVER THE AREA OF CONCERN AS THE UPPER
TROUGH MOVES EWD ACROSS SRN CANADA/ND THIS AFTERNOON COMBINED WITH
LOW-LEVEL CONVERGENCE SHOULD BE SUFFICIENT FOR THUNDERSTORMS TO
DEVELOP ALONG THE COLD FRONT BY 20-21Z AS IT REACHES FAR ERN ND. 
DEEP LAYER SHEAR WILL BE STRONG ENOUGH FOR ORGANIZED STORMS.  STRONG
FORCING AND MARGINAL INSTABILITY SUGGEST STORMS SHOULD REMAIN MORE
IN A LINE VERSUS BECOMING DISCRETE... DESPITE SHEAR VECTORS ORIENTED
PERPENDICULAR TO THE BOUNDARY.

..PETERS.. 05/21/2005

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

ATTN...WFO...MPX...FGF...ABR...BIS...

47989772 49009797 49009575 46619501 45979504 45969627
45969809

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 11:37 PM CDT	Mesoscale Discussion	SPC	Clay, Mahnomen, Norman, Pennington, Polk, Red Lake and 1 more	83 min
May 21, 1:08 AM CDT	Mesoscale Discussion	SPC	Big Stone, Clay, Grant, Lac qui Parle, Stevens, Traverse and 1 more	97 min
May 21, 1:35 AM CDT	Severe Thunderstorm Watch	SPC	Becker, Clay, Mahnomen, Marshall, Norman, Pennington and 3 more	7 hr
May 21, 4:52 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Mahnomen, Marshall, Norman, Pennington and 3 more	83 min
May 21, 7:43 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Mahnomen, Marshall, Norman, Pennington and 3 more	62 min
May 21, 3:15 PM CDT	Severe Thunderstorm Watch	SPC	Becker, Beltrami, Cass, Clay, Clearwater, Crow Wing and 13 more	6 hr
May 20, 9:30 PM CDT	Severe Thunderstorm Watch	SPC	McKenzie, Williams	5 hr
May 20, 10:45 PM CDT	Mesoscale Discussion	SPC	McKenzie, Williams	2 hr
May 21, 3:50 PM CDT	Mesoscale Discussion	SPC	Bottineau, Cavalier, McHenry, Pierce, Ramsey, Renville and 2 more	115 min

Nearby

Mesoscale Discussions in Minnesota, 2005 Mesoscale Discussions in North Dakota, 2005 Every mesoscale discussion in 2005

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.