Mesoscale Discussion 1693

Issued

Aug 3, 2012, 6:19 PM CDT (23:19 UTC)

Expired

Aug 3, 2012, 7:45 PM CDT

In force

86 min

Issued by

the Storm Prediction Center

The Aberdeen radar (KABR), 94 km from the middle of the area, began a volume at 23:22 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.

• Severe Thunderstorm Watch 554Aug 3, 7:15 PM CDT
• Severe Thunderstorm Watch 555Aug 3, 7:35 PM CDT

956 
ACUS11 KWNS 032319
SWOMCD
SPC MCD 032319 
MNZ000-IAZ000-NEZ000-SDZ000-NDZ000-040045-

MESOSCALE DISCUSSION 1693
NWS STORM PREDICTION CENTER NORMAN OK
0619 PM CDT FRI AUG 03 2012

AREAS AFFECTED...ERN ND/SD...WRN MN...N-CNTRL/NERN NEB...NWRN IA

CONCERNING...SEVERE THUNDERSTORM WATCH 553...

VALID 032319Z - 040045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 553
CONTINUES.

SUMMARY...CLUSTERS OF THUNDERSTORMS OVER ERN ND/SD WILL CONTINUE TO
POSE A SVR THREAT INTO THE EVENING...WITH UPSCALE GROWTH INTO A MORE
SOLID LINE POSSIBLE AS ACTIVITY ENTERS WRN MN AND NWRN IA. A NEW WW
MAY BE NEEDED E OF WW 553 DURING THE NEXT FEW HRS.  FARTHER S OVER
N-CNTRL/NERN NEB...THUNDERSTORM DEVELOPMENT ACCOMPANIED BY AN
ISOLATED SVR WEATHER THREAT WILL BE POSSIBLE ALONG A COLD FRONT
DURING THE EVENING/NIGHT.

DISCUSSION...AT 23Z...THUNDERSTORM CLUSTERS WERE ONGOING ALONG A
SURFACE COLD FRONT FROM NERN SD INTO ERN ND AND FAR NWRN MN.
INSTABILITY AXIS EXTENDED NWD ALONG THE MN/DAKOTAS BORDER...WITH
RESERVOIR OF HIGHEST MLCAPE VALUES IN EXCESS OF 2000 J/KG LOCATED
OVER ERN SD...SWRN MN AND NWRN IA. COMBINATION OF STRONG
CONVERGENCE/ASCENT ALONG THE COLD FRONT...FAVORABLE LAPSE
RATES/INSTABILITY...AND 0-6 KM BULK SHEAR AOA 40 KT MAY FAVOR THE
DEVELOPMENT OF A SVR SQUALL LINE AS THE EVENING PROGRESSES. GIVEN
THE PRESENCE OF LARGER CAPE VALUES AND A WIDER WARM SECTOR OVER ERN
SD INTO SWRN MN/NWRN IA...THREAT FOR DAMAGING WINDS AND LARGE HAIL
WILL BE MOST FAVORED IN THIS AREA DURING THE NIGHT. THUS...AREAS E
OF WW 553 WILL BE MONITORED FOR A NEW WW DURING THE NEXT FEW HRS.

FARTHER S OVER N-CNTRL/NERN NEB...SURFACE OBSERVATIONS AND AREA
PROFILERS/VWP/S INDICATE STRONG DEEP-LAYER CONVERGENCE ALONG COLD
FRONTAL SEGMENT ADVANCING SEWD INTO THE AREA. THIS WILL FAVOR
ISOLATED/SCATTERED THUNDERSTORM DEVELOPMENT DURING THE
EVENING...WITH A FEW STORMS POSING A THREAT FOR DAMAGING WINDS/LARGE
HAIL GIVEN THE PRESENCE OF A DRY SUB-CLOUD LAYER AND STEEP LAPSE
RATE ENVIRONMENT. CONVECTIVE TRENDS WILL BE MONITORED FOR POSSIBLE
INCLUSION IN FUTURE WW.

..GARNER.. 08/03/2012

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

ATTN...WFO...MPX...DMX...FGF...FSD...OAX...ABR...BIS...LBF...
UNR...

LAT...LON   48229924 48239604 44499421 42869471 42259692 41660133
            42610118 43329952 48229924

Mesoscale Discussions in South Dakota, 2012Mesoscale Discussions in Minnesota, 2012Mesoscale Discussions in Nebraska, 2012Every mesoscale discussion in 2012

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.