MESOSCALE DISCUSSION 1392
NWS STORM PREDICTION CENTER NORMAN OK
0357 PM CDT WED JUL 04 2012
AREAS AFFECTED...NE MN...LAKE SUPERIOR...UPPER MI
CONCERNING...SEVERE THUNDERSTORM WATCH 460...
VALID 042057Z - 042230Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 460
CONTINUES.
SUMMARY...THE SEVERE THREAT LOCATED ACROSS NE MN WILL LIKELY
CONTINUE THIS AFTERNOON. THE PRIMARY THREATS SHOULD BE WIND DAMAGE
AND ISOLATED LARGE HAIL AS A LINE APPROACHES UPPER MI. WW ISSUANCE
MAY BE NECESSARY TO THE EAST OF WW 460 AS THE LINE APPROACHES THE
ERN EDGE OF THE WATCH.
DISCUSSION...A BOWING LINE SEGMENT NEAR THE ARROWHEAD OF MN IS
LOCATED ON A TIGHT GRADIENT OF MODERATE INSTABILITY AND IS BEING
SUPPORTED BY A SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY.
MESOANALYSIS CURRENTLY SHOWS MLCAPE AROUND 1500 J/KG ACROSS NE MN
EXTENDING EWD ALONG THE SOUTH SHORT OF LAKE SUPERIOR. SOUTH OF LAKE
SUPERIOR ACROSS UPPER MI...STRONG INSTABILITY IS PRESENT WITH MLCAPE
ESTIMATED AROUND 4000 J/KG NEAR MARQUETTE. ALTHOUGH INSTABILITY IS
WEAKER OVER LAKE SUPERIOR...THE BOWING LINE SEGMENT APPEARS
WELL-DEVELOPED AND MAY REMAIN INTACT. IF THE BOWING LINE SEGMENT CAN
TURN ESEWD INTO THE GRADIENT OF STRONG INSTABILITY OVER UPPER
MI...THEN THE WIND DAMAGE THREAT COULD BECOME ENHANCED LATER THIS
AFTERNOON.
..BROYLES.. 07/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MQT...GRB...DLH...
LAT...LON 47128719 48219098 47789174 47069199 46409048 45688871
47128719
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