SWOMCD
SPC MCD 202045
WIZ000-MIZ000-MNZ000-202245-
MESOSCALE DISCUSSION 2197
NWS STORM PREDICTION CENTER NORMAN OK
0345 PM CDT TUE SEP 20 2011
AREAS AFFECTED...NORTHERN MN/WESTERN WI
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 202045Z - 202245Z
AN ISOLATED SEVERE THREAT...IN THE FORM OF WIND/HAIL AND/OR A BRIEF
TORNADO...MAY BE POSSIBLE LATE THIS AFTERNOON ACROSS NORTHEAST
MN/WESTERN WI.
WATER VAPOR IMAGERY REFLECTS A NEARLY STACKED CYCLONE CENTERED NEAR
THE ND/MN BORDER AT MID-AFTERNOON...WITH SURFACE ANALYSIS INDICATIVE
OF AN ARCING CONFLUENCE ZONE ACROSS NORTHERN MN SOUTHWARD TO
NEAR/WEST OF THE MS RIVER. THE PREVALENCE OF CLOUD COVER AND A
RELATIVELY COOL/MODESTLY MOIST AIRMASS IS EXPECTED TO LIMIT THE
OVERALL EXTENT/LIKELIHOOD OF SEVERE POTENTIAL. THAT SAID...POCKETS
OF MODEST CLEARING ARE OCCURRING /SUCH AS CURRENTLY NOTED ACROSS
NORTHEAST MN/ ALONG THE EAST-NORTHEAST ADVANCING SURFACE
BOUNDARY...AND SOME ADDITIONAL LOW-LEVEL HEATING IN THE PRESENCE OF
LOWER TO MIDDLE 50S F SURFACE DEWPOINTS MAY PROVE SUFFICIENT FOR
SUSTAINED/LIGHTNING-PRODUCING UPDRAFTS LATE THIS AFTERNOON/EARLY
EVENING. IN THE PRESENCE OF AMPLE AMBIENT VERTICAL
VORTICITY/RELATIVELY STRONG VERTICAL SHEAR/SRH AS OBSERVED PER
REGIONAL WSR-88D VWPS...A BRIEF TORNADO AND/OR STRONG WIND GUSTS
COULD OCCUR ASIDE FROM SMALL HAIL. ANY SUCH SEVERE THREAT IS
CURRENTLY EXPECTED TO BE MARGINAL/LOCALIZED IN NATURE...BUT
CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.
..GUYER.. 09/20/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MQT...GRB...DLH...ARX...MPX...
LAT...LON 47389392 48269386 47539140 46548994 44468969 44009183
45369209 46429257 47389392
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