MESO: Mesoscale Discussion 1737

ACUS11 KWNS 190034
SWOMCD
SPC MCD 190033
MNZ000-NDZ000-SDZ000-190200-

MESOSCALE DISCUSSION 1737
NWS STORM PREDICTION CENTER NORMAN OK
0733 PM CDT SUN AUG 18 2013

AREAS AFFECTED...NWRN MN/SERN ND/NCNTRL SD

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 190033Z - 190200Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE TSTMS ARE EXPECTED ALONG PRE-FRONTAL WIND
SHIFT ACROSS MN/ND/SD. THIS ACTIVITY SHOULD PROVE TOO SPARSE TO
WARRANT A WATCH.

DISCUSSION...LEAD SHORT-WAVE TROUGH OVER WRN ONTARIO IS MOSTLY
RESPONSIBLE FOR VEERED LOW LEVEL FLOW AND PRE-FRONTAL WIND SHIFT
ACROSS THE RED RIVER VALLEY. PRIMARY FRONTAL SURGE IS MORE EVIDENT
WITH SECONDARY SHORT-WAVE TROUGH LOCATED OVER MB/ND. OVER THE LAST
HOUR OR SO A LONE SEVERE TSTM HAS DEVELOPED ALONG THE PRE-FRONTAL
WIND SHIFT OVER MARSHALL COUNTY MN. EVEN SO...NEW CONVECTION MAY
STRUGGLE TO EVOLVE GIVEN THAT STRONGER FORCING REMAINS CONSIDERABLY
UPSTREAM ACROSS ND. 00Z SOUNDINGS FROM THIS REGION EXHIBIT STEEP
LAPSE RATES BUT VERY STRONG MID LEVEL CAPPING CURRENTLY RESIDES
ACROSS NRN SD...PER ABR PROFILE. LATEST THINKING IS LARGE SCALE
FORCING MAY RESULT IN MOST SUBSTANTIAL CONVECTION REMAINING
POST-FRONTAL AND ONLY VERY ISOLATED ACTIVITY ACTUALLY EVOLVING ALONG
THE SFC WIND SHIFT WHERE HIGHER MOISTURE/BUOYANCY RESIDES. LARGE
HAIL LIKELY ACCOMPANIES THE NWRN MN STORM AND THIS IS THE PRIMARY
SEVERE THREAT WITH STORMS THAT MANAGE TO MATURE NEAR THE HIGHER
QUALITY INSTABILITY. GIVEN THE SPARSE COVERAGE DO NOT ANTICIPATE
SEVERE THUNDERSTORM WATCH AT THIS TIME.

..DARROW/MEAD.. 08/19/2013

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

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

LAT...LON 45380044 46570002 47039829 48039725 48959620 48559464
46479699 45169902 45380044

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