Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 210530
SWOMCD
SPC MCD 210529
MNZ000-SDZ000-NDZ000-210730-

MESOSCALE DISCUSSION 1591
NWS STORM PREDICTION CENTER NORMAN OK
1229 AM CDT THU AUG 21 2014

AREAS AFFECTED...FAR EASTERN SD INTO CENTRAL/SOUTHERN MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 210529Z - 210730Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THE POTENTIAL FOR AT LEAST ISOLATED BOUTS OF LARGE HAIL
ARE EXPECTED TO INCREASE OVERNIGHT FROM FAR EASTERN SD INTO
CENTRAL/SOUTHERN MN. MONITORING CONVECTIVE TRENDS FOR A POSSIBLE
WATCH.

DISCUSSION...ELEVATED STRONG/SEVERE THUNDERSTORMS CONTINUE TO
INCREASE NEAR/JUST EAST OF THE SD/MN BORDER VICINITY AS OF
0515Z...WITH THESE STORMS PRECEDING A SMALL/LOOSELY ORGANIZED
CONVECTIVE COMPLEX ACROSS NORTHEAST SD. NEAR THE CREST OF A
SHORTWAVE RIDGE...THIS INCREASE IN ELEVATED CONVECTIVE DEVELOPMENT
IS BEING AIDED BY A RELATIVELY STRONG LOW-LEVEL JET AND UNSTABLE
SOURCE REGION AIR MASS. LATEST WSR-88D VWP DATA FROM SIOUX FALLS
SD/OMAHA NEB ARE SAMPLING A 40 KT SOUTHWESTERLY LOW-LEVEL JET...WITH
AN EARLIER 00Z OBSERVED SOUNDING FROM OMAHA SAMPLING A VERY UNSTABLE
SOURCE REGION WITH NEARLY 7.5 C/KM MID-LEVEL LAPSE RATES AND 5000+
J/KG MOST-UNSTABLE CAPE. AS WARM ADVECTION/ISENTROPIC ASCENT
SUPPORTS AN INCREASING NUMBER OF STORMS...THE STRONGEST ACTIVITY
WILL BE CAPABLE OF LARGE HAIL ACROSS CENTRAL/SOUTHERN PORTIONS OF
MN. WHILE LARGE HAIL IS THE PRIMARY RISK GIVEN A RELATIVELY STABLE
BOUNDARY LAYER...LOCALLY STRONG WIND GUSTS CANNOT BE ENTIRELY RULED
OUT...ESPECIALLY IF STORM MERGERS/UPSCALE TRENDS OCCUR OVER TIME.

..GUYER/CARBIN.. 08/21/2014

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

ATTN...WFO...DLH...MPX...FGF...FSD...ABR...

LAT...LON   46579487 45619346 43929312 43629531 44939730 45959716
            46579487




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