Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 020708
SWODY3
SPC AC 020707

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0207 AM CDT TUE SEP 02 2014

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS WI AND THE U.P. OF MI...

...SUMMARY...
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS WISCONSIN AND THE
U.P. OF MICHIGAN THURSDAY.

...UPPER GREAT LAKES...

A CONDITIONAL SEVERE THUNDERSTORM THREAT IS EXPECTED ACROSS THE
UPPER GREAT LAKES REGION DURING THE DAY3 PERIOD.  LATEST SHORT-RANGE
MODEL GUIDANCE DEPICTS A STRONG MID-LEVEL SPEED MAX THAT WILL EJECT
ACROSS THE NRN PLAINS INTO THE ARROWHEAD OF MN BY 05/00Z WITH A
CORRIDOR OF 70KT+ 500MB FLOW EXPECTED TO EXTEND ACROSS NRN MN INTO
NWRN ONTARIO.  WHILE CONCENTRATED UVV WILL BE NORTH OF THE
INTERNATIONAL BORDER...PRONOUNCED SFC FRONT IS EXPECTED TO ADVANCE
INTO WRN WI BY EARLY AFTERNOON.  ADDITIONALLY...STOUT CAP IS
EXPECTED TO EXTEND ACROSS THE CNTRL PLAINS INTO WCNTRL WI WHERE A
PLUME OF VERY WARM 700MB AIR WITH TEMPERATURES AOA 12C ARE EXPECTED
AT DAYBREAK.  THUNDERSTORMS MAY STRUGGLE TO INITIATE ACROSS THE WARM
SECTOR BUT MODELS SUGGEST FORCING ALONG COLD FRONT...AND LATE DAY
MID-LEVEL COOLING...COULD BE SUFFICIENT FOR THUNDERSTORM DEVELOPMENT
ROOTED IN THE BOUNDARY LAYER.  BOTH THE NAM AND GFS SUGGEST SBCAPE
SHOULD EXCEED 3000 J/KG WITH SFC DEW POINTS AOA 70F.  DEEP SWLY FLOW
AND 40-50KT AT 500MB SUGGEST ANY STORMS THAT DEVELOP COULD
ORGANIZE...MOVING QUICKLY DOWNSTREAM WITHIN A REGIME FAVORABLE FOR
DAMAGING WINDS AND LARGE HAIL.  SWRN EXTENT OF WARM SECTOR
CONVECTION SHOULD BE NEAR THE WI/IA BORDER WITH ANY TRAILING STORMS
LIKELY EVOLVING WITHIN A POST-FRONTAL ENVIRONMENT ACROSS THE CNTRL
PLAINS.

..DARROW.. 09/02/2014




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