Alert archive / Minnesota / Mesoscale Discussions in 2005

Mesoscale Discussion 939

May 20, 20059 counties in Minnesota; 5 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at May 20, 2005, 5:55 PM CDT for 9 counties in Minnesota; 5 counties in North Dakota. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
May 20, 2005, 5:55 PM CDT (22:55 UTC)
Expired
May 20, 2005, 7:00 PM CDT
In force
65 min
Issued by
the Storm Prediction Center

Counties Becker County, MN, Clay County, MN, Clearwater County, MN, Mahnomen County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Ransom County, ND, Richland County, ND, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 66 km from the middle of the area, began a volume at 22:55 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.

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.9 hours before the alert went out and 290 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, Aberdeen, SD at 12:00Z on 2005-05-20Temperature 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, Aberdeen, SD at 12:00Z on 2005-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1627 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
37 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 202255
SWOMCD
SPC MCD 202255 
MNZ000-NDZ000-210000-

MESOSCALE DISCUSSION 0939
NWS STORM PREDICTION CENTER NORMAN OK
0555 PM CDT FRI MAY 20 2005

AREAS AFFECTED...NWRN/NCENTRAL SD AND SWRN/SCENTRAL ND

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 202255Z - 210000Z

ISOLATED STG STORM OVER CARTER COUNTY WILL LIKELY CONTINUE TO
INTENSIFY AS IT MOVES ENEWD TOWARDS HARDING COUNTY SD AND BOWMAN
COUNTY ND. ADDITIONAL ISOLATED SVR DEVELOPMENT IS POSSIBLE ALONG SFC
FRONTAL BOUNDARY EXTENDING FROM SWRN ND TO JUST EAST OF BIS. CURRENT
TRENDS INDICATE THAT A WW WILL LIKELY BE ISSUED SOON.

SFC ANALYSIS SHOWS BOUNDARY EXTENDING FROM FAR SERN MT NEWD TO JUST
EAST OF BIS. AIRMASS OVER THE AREA REMAINS CAPPED...WITH MLCINH
AROUND 100 J/KG. HOWEVER...RECENT VISIBLE IMAGERY SUGGESTS THAT CAP
WAS ERODING TO THE EAST OF BIS AND OVER CARTER COUNTY MT. LOW LEVEL
JET IS FORECAST TO INTENSIFY OVER THE NEXT FEW HOURS. COMBINATION OF
INCREASED LIFT WITH THE LOW LEVEL JET AND MODERATE INSTABILITY
SUGGESTS SVR THREAT SHOULD PERSIST WELL INTO THE EVENING HOURS.

..CROSBIE.. 05/20/2005

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

ATTN...WFO...FGF...BIS...

48109614 47629718 47009821 46779845 46269810 46189749
46099687 46199618 47259536 47789504 48059527 48129545

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 1:39 PM CDTMesoscale DiscussionSPCClay, Kittson, Marshall, Norman, Pennington, Polk and 2 more2 hr
May 20, 5:23 PM CDTMesoscale DiscussionSPCBecker, Clay, Clearwater, Mahnomen, Norman, Pennington and 3 more97 min
May 20, 6:10 PM CDTSevere Thunderstorm WatchSPCBecker, Clay, Mahnomen, Norman, Otter Tail, Polk and 2 more8 hr

Nearby

Mesoscale Discussions in Minnesota, 2005Mesoscale Discussions in North Dakota, 2005Every 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.