MESO: Mesoscale Discussion 1671

ACUS11 KWNS 202356
SWOMCD
SPC MCD 202355
MIZ000-MNZ000-WIZ000-210130-

MESOSCALE DISCUSSION 1671
NWS STORM PREDICTION CENTER NORMAN OK
0655 PM CDT WED JUL 20 2011

AREAS AFFECTED...NRN MN...NRN WI...WRN LAKE SUPERIOR...WRN UPPER MI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 202355Z - 210130Z

SEVERE STORM DEVELOPMENT MAY OCCUR ACROSS NCNTRL AND NERN MN EARLY
THIS EVENING. ISOLATED LARGE HAIL AND WIND DAMAGE WILL BE POSSIBLE
AS STORMS INITIATE AND INCREASE IN COVERAGE. WW ISSUANCE MAY BECOME
NECESSARY ONCE THE TIME OF INITIATION BECOMES MORE CERTAIN.

AN AXIS OF MODERATE INSTABILITY IS CURRENTLY LOCATED FROM NW WI
NNWWD ACROSS NCNTRL MN WHERE MESOANALYSIS ESTIMATES MLCAPE VALUES
RANGE FROM 2500 TO 3500 J/KG. A COLD FRONT IS EVIDENT ON SFC
ANALYSIS ACROSS NCNTRL NM WITH RADAR IMAGERY SUGGESTING CELLS ARE
TRYING TO INITIATE ALONG THIS BOUNDARY. SEVERE STORMS WILL BE
POSSIBLE IN NCNTRL MN IF SFC-BASED THUNDERSTORMS CAN DEVELOP THIS
EVENING. FURTHER TO THE EAST NEAR THE BOUNDARY WATERS...A LINE OF
STRONG THUNDERSTORMS IS ONGOING ALONG A WARM FRONT EXTENDING SEWD
ACROSS LAKE SUPERIOR. THIS LINE MAY INTENSIFY AND MOVE SEWD INTO THE
ARROWHEAD OF MN AND WRN LAKE SUPERIOR OVER THE NEXT FEW HOURS.
REGIONAL WSR-88D VWPS SHOW MODERATE TO STRONG DEEP LAYER SHEAR
PROFILES EXIST ACROSS NCNTRL AND NERN MN WHICH WILL BE FAVORABLE FOR
SEVERE STORMS. IN ADDITION...MESOANALYSIS SHOWS A PLUME OF STEEP
MID-LEVEL LAPSE RATES WHICH COMBINED WITH THE STRONG INSTABILITY
SHOULD BE FAVORABLE FOR ISOLATED LARGE HAIL. A WIND DAMAGE THREAT
MAY ALSO EXISTS ESPECIALLY IF THE LINE SEGMENT NEAR THE MN AND
ONTARIO BORDER CAN DEVELOP A BOWING STRUCTURE.

..BROYLES.. 07/20/2011

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

ATTN...WFO...MQT...DLH...FGF...

LAT...LON 46309171 46348973 46698838 47168789 47548791 48108882
48349042 48599246 48809357 48789415 48569459 48099475
47389467 46879445 46419378 46239259 46309171

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